Moparts

Grounding for battery in the trunck?

Posted By: gregsdart

Grounding for battery in the trunck? - 01/05/15 04:38 PM

I have had great success running a rear battery and using the cage for a ground for the most part. I ground the heads AND block to the frame, use two 3/8 bolts welded to the frame, one for the electronics and one for the starter circuit.
My question is, for my street dart there is no cage, and I am moving the battery to the back. I am looking for a good way to ground the battery and thought that the same system would work, provided the ground connections are big enough (bolt welded all around the head?)to not create resistance at those points. I would drill a hole in the floor at the subframe area and weld it to the sub. The car has frame connectors. Input?
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/05/15 04:45 PM

Quote:

I have had great success running a rear battery and using the cage for a ground for the most part. I ground the heads AND block to the frame, use two 3/8 bolts welded to the frame, one for the electronics and one for the starter circuit.
My question is, for my street dart there is no cage, and I am moving the battery to the back. I am looking for a good way to ground the battery and thought that the same system would work, provided the ground connections are big enough (bolt welded all around the head?)to not create resistance at those points. I would drill a hole in the floor at the subframe area and weld it to the sub. The car has frame connectors. Input?




Since electricity travels on the exterior of the wire
(and the cage tubing) the cage isnt the best... so they
say.. I have never had any issue doing the same thing
on the cage as you.. and thats the way I set up my
Rampage.. I will tell you how the EFI likes that
ground system.. but I have no doubt its fine
Posted By: Thumperdart

Re: Grounding for battery in the trunck? - 01/05/15 04:46 PM

I have zero issues and 14.7 volts at the hit and running w/my batt. grounds bolted to rear bumper bolts. I have several grounds from engine to firewall, frame etc. I like your ideas though for a cleaner look but mines all hidden anyhow.
Posted By: mopar dave

Re: Grounding for battery in the trunck? - 01/05/15 05:03 PM

I had my trunk mounted battery grounded to the frame right under the battery for years. worked great,no issues. had one of the major ignition box company's tell to ground everything to engine block. so I did using 1ga. multi strand welding cable. now my starter sounds like it labors abit when I first hit the button. i'd ground it as close to the bat. as possible.
Posted By: Just-a-dart

Re: Grounding for battery in the trunck? - 01/05/15 05:05 PM

The last couple of timesI have done this I used a lug with 2 bolts on a small plate with 2 taped holes welded to the frame rail. Put a dab of grease under the lug. http://www.grainger.com/product/BURNDY-C..._AW01?$smthumb$
Posted By: StealthWedge67

Re: Grounding for battery in the trunck? - 01/05/15 06:00 PM

I've had great success with my setup thus far: 2g ground cable through the trunk floor, and bolted to the frame rail; then a 4g cable from that same spot forward, bolted to the head, and a simple ground strap from that spot back to the firewall.

Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/05/15 06:16 PM

I run my ground to the front where my electronics are. ground issues can kill you. I don't think you will find any makers of electronics telling you to use a roll bar or frame as a ground. and yes I have seen people doing it for years. I just choose to do it right..
Posted By: Jeremiah

Re: Grounding for battery in the trunck? - 01/05/15 06:20 PM

I have done it both ways. My red Charger has been running around on the street for ten years with the battery grounded to the rear frame rail. MSD7AL, two step, etc. all function flawlessly.
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/05/15 06:29 PM

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.
Posted By: tubtar

Re: Grounding for battery in the trunck? - 01/05/15 06:59 PM

I welded a 3/8" bolt to the rear frame rail.......works like a champ.
Multiple grounds from starter and engine block to frame.
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/05/15 07:08 PM

I used two #2 ground straps off of the battery in my Duster, one went to the stock hole in the wheelwell flange on the passenger side and the other went to one of the bolts Thumper is using I have drilled through the trunk floor through the sub frame flanged with one ground strap and had issues with the starter laboring on the hit when the motor was warm, ended up melting the battery post lugs and the lead clamps on the cables I do use multiple grounds off of the block to the front sub frames also
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/05/15 07:18 PM

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte
Posted By: dartman366

Re: Grounding for battery in the trunck? - 01/05/15 08:06 PM

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte


this is they way I did it back in the day and it still functions correctly, I had run the main ground from the battery to the frame then ran a 08 ground wire to the buss and ran all my grounds to that,,engine,electronics etc.
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/05/15 11:16 PM

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte


but the individual circuit voltage loss between the 2 systems is negligible, and just not practical in most instance's. Use the frame or 1000 feet of wire? I could see it for some "highly sensitive" circuits, but to run a fan, water pump, or a fuel pump, etc., not needed.
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/05/15 11:21 PM

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte


exactly, thats the way I do them also
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/05/15 11:22 PM

Quote:

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte


but the individual circuit voltage loss between the 2 systems is negligible, and just not practical in most instance's. Use the frame or 1000 feet of wire? I could see it for some "highly sensitive" circuits, but to run a fan, water pump, or a fuel pump, etc., not needed.


not really but you can do it that way if you like.
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/06/15 12:37 AM

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte



Lets look at a new Charger or Challenger. Battery in the trunk, tons of components that are Can Bus based. Cars are even sent to the lab to check for radio and magnetic interference. Guess where the ground connects? Frame rail next to the battery. What do you think?
Doug
Posted By: NOM36

Re: Grounding for battery in the trunck? - 01/06/15 01:36 AM

My race car had a ground to frame and the previous 3 engines (6 cyl, Sml block, Big Block) were all fine. Forth engine (500ci BB on alcohol had an ever so slight miss. Grounded heads and block to separate cable back to battery and ran clean as after that.

I didn't believe it to start with, but I do now.
Posted By: dogdays

Re: Grounding for battery in the trunck? - 01/06/15 02:08 AM

I was imagining a solid copper bus bar from front bumper to rear.

The statement that current runs on the outside of the conductor is partially true, the least true for DC. When the current starts to alternate it moves to the outside of the conductor, the faster the current alternates the more it bunches up at the outside. It's called the "skin effect".

R.
Posted By: CHAPPER

Re: Grounding for battery in the trunck? - 01/06/15 02:50 AM

Quote:

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte



Lets look at a new Charger or Challenger. Battery in the trunk, tons of components that are Can Bus based. Cars are even sent to the lab to check for radio and magnetic interference. Guess where the ground connects? Frame rail next to the battery. What do you think?
Doug





Frame has high copper content.
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/06/15 03:41 AM

Quote:

Quote:

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte



Lets look at a new Charger or Challenger. Battery in the trunk, tons of components that are Can Bus based. Cars are even sent to the lab to check for radio and magnetic interference. Guess where the ground connects? Frame rail next to the battery. What do you think?
Doug





Frame has high copper content.


Posted By: Sport440

Re: Grounding for battery in the trunck? - 01/06/15 04:21 AM

Quote:

Quote:

Quote:

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte



Lets look at a new Charger or Challenger. Battery in the trunk, tons of components that are Can Bus based. Cars are even sent to the lab to check for radio and magnetic interference. Guess where the ground connects? Frame rail next to the battery. What do you think?
Doug





Frame has high copper content.








Along with some silver and gold I heard.
Posted By: Sport440

Re: Grounding for battery in the trunck? - 01/06/15 05:52 AM

Quote:

I have had great success running a rear battery and using the cage for a ground for the most part. I ground the heads AND block to the frame, use two 3/8 bolts welded to the frame, one for the electronics and one for the starter circuit.
My question is, for my street dart there is no cage, and I am moving the battery to the back. I am looking for a good way to ground the battery and thought that the same system would work, provided the ground connections are big enough (bolt welded all around the head?)to not create resistance at those points. I would drill a hole in the floor at the subframe area and weld it to the sub. The car has frame connectors. Input?





IMO, the way you suggested is Fine and maybe overkill.

IMO, where people go wrong is when they bolt a battery end against a painted surface#1 Number#2, they don't make sure they have good grounds from the engine to the body.

IMO, the unibody works fine as a ground circuit as long as every ground connection is clean and solid.

That's where the problem lies with some that have had problems. Bolt the neg to a painted surface and don't bother to check the quality of the engine ground to the body. Problems!!


I run two separate neg grounds to the engine from the body. I run the bat neg to a quality ground to the factory multi welded trunk brace. Never a problem. Greg, your methods will work fine.
Posted By: Stanton

Re: Grounding for battery in the trunck? - 01/07/15 12:23 AM

A lot of electronics like a dedicated ground cable to the battery. The ground ensures they don't get nuisance calls on the tech line because of bad grounds. Who can blame them. On the flip side, the starter draws more current than ANY other component - and its grounded through the casing/block/chassis.

Posted By: gregsdart

Re: Grounding for battery in the trunck? - 01/07/15 02:51 AM

One thing we can agree on, there needs to be good grounds from the heads and block to where ever the main ground is. I also like to use a ground right to a starter mounting bolt. The heads and block ground can be much smaller if you are using a big ground independently for the starter.
Posted By: 383man

Re: Grounding for battery in the trunck? - 01/07/15 03:23 AM

I ground my trunk mounted battery to the body in the trunk. But I have a few extra grounds from the frame to the unibody and an extra one from the eng to the body. Working for a Dodge dealer for 24 years I would see some strange ground problems over the years like the one that causes the trans bearing to have problems or seeing sparks from a throttle cable because the body to eng ground is bad. So in my opinion if your not sure put another ground on it as you can not have to many grounds. Ron
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/07/15 04:08 AM

Soooo, what's everyone's opinion on running static straps for them highly sensitive electronics?
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/07/15 05:16 PM

I am not sure I agree, I would rather have one reliable, properly sized, tested/measured ground, then, unless in an in an emergency, a random selection of undersized, maybe good grounds, and let the electrical devices figure which one is best. IE, if a ground is thought to be not correct, then any additional backup grounds have to all be the same proper size, thinking you can "share" or combine grounds is unwise and asking for future problems.

"static straps", are primarily for grounding static charges, not grounds.
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/07/15 05:48 PM

Quote:

I am not sure I agree, I would rather have one reliable, properly sized, tested/measured ground, then, unless in an in an emergency, a random selection of undersized, maybe good grounds, and let the electrical devices figure which one is best. IE, if a ground is thought to be not correct, then any additional backup grounds have to all be the same proper size, thinking you can "share" or combine grounds is unwise and asking for future problems.

"static straps", are primarily for grounding static charges, not grounds.


"properly sized" - would a frame be big enough?
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/07/15 05:58 PM

A ground is NOT a ground so to speak. Lot to be said for "clean" grounds and "noisy" grounds. Something like a starter, doesn't NEED a clean ground.......ANYTHING electronic DOES. You want to use the chassis as one big ground conductor, that's fine, many do, but it is NOT the best way to do it. I prefer to do it right and prevent any future issues. Seen too many problems too many times that drove guys crazy, that was fixed with a proper ground system.

I used to ground stuff like everybody else, to the chassis, until I learned better. Just because it is the way you have ALWAYS done something doesn't mean its the BEST way. You would like to think you do something long enough, that you find BETTER ways to do it........not the same old same oh.

Monte
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/07/15 06:33 PM

Quote:

A ground is NOT a ground so to speak. Lot to be said for "clean" grounds and "noisy" grounds. Something like a starter, doesn't NEED a clean ground.......ANYTHING electronic DOES. You want to use the chassis as one big ground conductor, that's fine, many do, but it is NOT the best way to do it. I prefer to do it right and prevent any future issues. Seen too many problems too many times that drove guys crazy, that was fixed with a proper ground system.

I used to ground stuff like everybody else, to the chassis, until I learned better. Just because it is the way you have ALWAYS done something doesn't mean its the BEST way. You would like to think you do something long enough, that you find BETTER ways to do it........not the same old same oh.

Monte




While this is true, I've seen that more wires CAN
create more issues... like is it REALLY grounded after
its been on there a while
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/07/15 08:43 PM

Quote:

A ground is NOT a ground so to speak. Lot to be said for "clean" grounds and "noisy" grounds. Something like a starter, doesn't NEED a clean ground.......ANYTHING electronic DOES. You want to use the chassis as one big ground conductor, that's fine, many do, but it is NOT the best way to do it. I prefer to do it right and prevent any future issues. Seen too many problems too many times that drove guys crazy, that was fixed with a proper ground system.

I used to ground stuff like everybody else, to the chassis, until I learned better. Just because it is the way you have ALWAYS done something doesn't mean its the BEST way. You would like to think you do something long enough, that you find BETTER ways to do it........not the same old same oh.

Monte


I agreed with your post - in principal, but you gotta look at the bigger picture some times. For instance, is the added weight of having to run a ground cable from a rear mounted battery to the front of the car off set by the better conductivity of the cable over the frame? Doubt if you could measure the difference. The reason that it is still done the way it was done 30 years ago is because nothing "practically" better has come along. Change for the sake of change is not better. Who ever coined the phrase "change is good" must be in sales. Who ever invented "scotch-locks" should be shot. Minimum wiring, minimum ( and clean ) connections, still the best bet IMO.
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/07/15 08:55 PM

Quote:

Quote:

I am not sure I agree, I would rather have one reliable, properly sized, tested/measured ground, then, unless in an in an emergency, a random selection of undersized, maybe good grounds, and let the electrical devices figure which one is best. IE, if a ground is thought to be not correct, then any additional backup grounds have to all be the same proper size, thinking you can "share" or combine grounds is unwise and asking for future problems.

"static straps", are primarily for grounding static charges, not grounds.


"properly sized" - would a frame be big enough?




Yes, most definitely but may not be properly electrically connected, circumventing the benefits of being properly sized. In my previous reply example I intended the "properly sized" to more refer to any of the wiring size that is being used to connect to the battery Negative. The chassis is just a multi sheet metal steel welded sometimes questionable conductor in that goal.
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/07/15 10:32 PM

Years ago, 1976 to 1990, the telephone industry went from old analog mechanical equiptment to digiatl computer to do the calling, billing and offer a lot of features we now know as standards. The conversion process and the debugging took a lot of work and energy as well as dicovering some new ways to get the job done without problems, grounding being a big factor in noise and problem prevention. All the phone companys I know of use banks of batterys to power the equiptment offices, we used commercial power ran through inverters to charge the batterys but all the equiptment drew its power from the battery banks. The reason I'm clarifying this is all power, voltage and amperage, comes out of ALL batterys from the negatve battery post and travels through the circuit and returns back to the positive post My main point is we had to convert our grounding(positive side) in the offices from conventional to perephial grounding, we had copper buss bars aroud two to three inches tall by 1/4 inch thick, depending on the office size and the power used, running all the way around the equiptment in the offices with multiple 000 or larger ground wires hook to them We lived in the Mojave Desert in SO CA and the summer thunderstorms could wreak havoc with the digital offices through the air and telephone lines Noise can be induced from many sources into digital devices is my message. You can never have to good of a ground on any thing using electrical power to run digital devices IHTHs someone
Posted By: Plumb Wired

Re: Grounding for battery in the trunck? - 01/07/15 11:22 PM

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte




I agree 100%, this is the ONLY way I will wire a car!

Mike Gray
Plumb Wired
Posted By: LAD 524

Re: Grounding for battery in the trunck? - 01/08/15 12:05 AM


What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte




Monte, I assume you run the MAIN -ve batt cable to the bus bar under the dash so that the bus bar gets is grounding from the batt cable itself, and NOT the body ? Or in other words, the bus bar is NOT grounded to the body/mounted on isolators/non conductive mounts....right?

That would be a decent gauge cable if thats the case - do you run it inside the car ?
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/08/15 12:13 AM

If anything is grounded to the chassis, and he said the lights are, this floating ground buss bar, must also have a connection to the chassis someplace, or no lights. This is the best in our situations, and most complex(?) solution, and a bad ground is a lot easier to trouble shoot, and all grounds are very close to the same resistance.
Posted By: Dean_Kuzluzski

Re: Grounding for battery in the trunck? - 01/08/15 12:46 AM

The "bussbar" would be for electronic devices that NEED a "clean" ground free from noise. And that same bussbar would have its own dedicated cable to the battery. The whole idea is to separate/isolate the high tech digital devices away from the old school analog devices like alternators, wiper motors, headlights and such. Motors and alternators create electromagnetic fields that cause noise.

When it comes to the starter motor......it is the highest current drawing device in the vehicle. Of course it needs just as high current carrying a path as the positive cable that feeds the starter (A basic law of DC voltage). One little ground strap is not going to do it. If the motor is solid mounted, it should be fine.

High current devices like, headlights, starter motors, wiper motors, when poorly connected will seek the path of least resistance creating a "groundshift" or a voltage drop that causes more problems for sophisticated devices like electronic modules.

Bottomline.......run a separate ground for your ignition modules/boxes and otherwise the use of the rollcage is perfectly acceptable for the rest of the old school automotive circuits.

And the electron flow is within the metal of the wire (copper being best) but the electromagnetic field travels along its outer layer.
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/08/15 01:29 AM

No one has answered how production cars with numerous electronic devices rely on the "terrible" floor pan/unibody to attach ALL the grounds in the entire vehicle. This remains the same regardless of where the battery is located. There is a heck a lot of surface area in a unibody. I do agree if the car is a rust bucket the unibody spot welds could possibly be an issue. If its so bad that the majority of the spot welds are suspect there is a way bigger issue than the ground path. When my car was completed I voltage drop tested my ground side under load. There was .2 volts drop at 28 amp draw from the center ground post of the battery to the ground wire of the dual cooling fans. The battery is grounded to a 3/8" stud welded to the cage with 1awg cable. The block/trans is also grounded with 1awg cable.
Doug
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/08/15 02:59 AM

Quote:

Quote:

A ground is NOT a ground so to speak. Lot to be said for "clean" grounds and "noisy" grounds. Something like a starter, doesn't NEED a clean ground.......ANYTHING electronic DOES. You want to use the chassis as one big ground conductor, that's fine, many do, but it is NOT the best way to do it. I prefer to do it right and prevent any future issues. Seen too many problems too many times that drove guys crazy, that was fixed with a proper ground system.

I used to ground stuff like everybody else, to the chassis, until I learned better. Just because it is the way you have ALWAYS done something doesn't mean its the BEST way. You would like to think you do something long enough, that you find BETTER ways to do it........not the same old same oh.

Monte


I agreed with your post - in principal, but you gotta look at the bigger picture some times. For instance, is the added weight of having to run a ground cable from a rear mounted battery to the front of the car off set by the better conductivity of the cable over the frame? Doubt if you could measure the difference. The reason that it is still done the way it was done 30 years ago is because nothing "practically" better has come along. Change for the sake of change is not better. Who ever coined the phrase "change is good" must be in sales. Who ever invented "scotch-locks" should be shot. Minimum wiring, minimum ( and clean ) connections, still the best bet IMO.


Wire a few EFI cars.....chase your ass for weeks with EMI "noise" and get back to me on if its "worth" it

Monte
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/08/15 03:41 AM

"copper being best"

Not busting your chops, but Audi uses pure silver for wiring on its Kerv racing cars, being slightly better then copper for the task.
Posted By: Duner

Re: Grounding for battery in the trunck? - 01/08/15 04:48 AM

Quote:

Wire a few EFI cars.....chase your ass for weeks with EMI "noise" and get back to me on if its "worth" it

Monte




Hahaha.... I've been chasing my tail trying to get rid of noise on my TPS signal forever.... and I haven't even moved my battery yet. Who knows, bigger cable and better grounds might just fix it yet!
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/08/15 04:58 AM

Quote:

Quote:

Quote:

A ground is NOT a ground so to speak. Lot to be said for "clean" grounds and "noisy" grounds. Something like a starter, doesn't NEED a clean ground.......ANYTHING electronic DOES. You want to use the chassis as one big ground conductor, that's fine, many do, but it is NOT the best way to do it. I prefer to do it right and prevent any future issues. Seen too many problems too many times that drove guys crazy, that was fixed with a proper ground system.

I used to ground stuff like everybody else, to the chassis, until I learned better. Just because it is the way you have ALWAYS done something doesn't mean its the BEST way. You would like to think you do something long enough, that you find BETTER ways to do it........not the same old same oh.

Monte


I agreed with your post - in principal, but you gotta look at the bigger picture some times. For instance, is the added weight of having to run a ground cable from a rear mounted battery to the front of the car off set by the better conductivity of the cable over the frame? Doubt if you could measure the difference. The reason that it is still done the way it was done 30 years ago is because nothing "practically" better has come along. Change for the sake of change is not better. Who ever coined the phrase "change is good" must be in sales. Who ever invented "scotch-locks" should be shot. Minimum wiring, minimum ( and clean ) connections, still the best bet IMO.


Wire a few EFI cars.....chase your ass for weeks with EMI "noise" and get back to me on if its "worth" it

Monte


Ok
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/08/15 05:28 AM

Quote:

"copper being best"

Not busting your chops, but Audi uses pure silver for wiring on its Kerv racing cars, being slightly better then copper for the task.


Silver is NOT the best conductor of electricity, gold is I think copper is number four and I can't remember if silver is number two or three I believe aluminum is number 7 or lower. Tin and silver plated copper holds up well to corrosion, but gold is the hot setup for the least resistance, best against corrosion and the best conducting
Posted By: 383man

Re: Grounding for battery in the trunck? - 01/08/15 05:41 AM

Quote:

I am not sure I agree, I would rather have one reliable, properly sized, tested/measured ground, then, unless in an in an emergency, a random selection of undersized, maybe good grounds, and let the electrical devices figure which one is best. IE, if a ground is thought to be not correct, then any additional backup grounds have to all be the same proper size, thinking you can "share" or combine grounds is unwise and asking for future problems.

"static straps", are primarily for grounding static charges, not grounds.





My point was not to have a bunch of undersize grounds. My point was its nothing wrong with adding a ground of the correct size even if you already have a ground of the correct size in whatever circuit you are working with. Hence the saying .....you can never have to many grounds. Ron
Posted By: RobX4406

Re: Grounding for battery in the trunck? - 01/08/15 06:13 AM

Quote:

The most electrically conductive element is silver, followed by copper and gold. Silver also has the highest thermal conductivity of any element and the highest light reflectance. Although it is the best conductor, copper and gold are used more often in electrical applications because copper is less expensive and gold has a much higher corrosion resistance.




http://chemistry.about.com/od/elements/f/What-Is-The-Most-Conductive-Element.htm


I run my cars much like Monty suggest. I ground the frame and run a dedicated ground circuit for sensitive electronic/ignition.

One thing to watch for on cars is ground looping. It may create static and noise.
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/08/15 07:28 AM

Posted By: dvw

Re: Grounding for battery in the trunck? - 01/08/15 01:30 PM

I run a twisted pair with shielding and a shielding ground wire from the MSD box to both the coil and the crank trigger. However the box is grounded to the cage like everything else.
Doug
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/08/15 06:14 PM

Quote:

No one has answered how production cars with numerous electronic devices rely on the "terrible" floor pan/unibody to attach ALL the grounds in the entire vehicle. This remains the same regardless of where the battery is located. There is a heck a lot of surface area in a unibody. I do agree if the car is a rust bucket the unibody spot welds could possibly be an issue. If its so bad that the majority of the spot welds are suspect there is a way bigger issue than the ground path. When my car was completed I voltage drop tested my ground side under load. There was .2 volts drop at 28 amp draw from the center ground post of the battery to the ground wire of the dual cooling fans. The battery is grounded to a 3/8" stud welded to the cage with 1awg cable. The block/trans is also grounded with 1awg cable Doug


I think you are missing the point on race cars, it's not a voltage drop issue. it is a noise issue and old analog ignitions may never have a problem. but with new digital race ignitions it is an issue.
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/08/15 06:28 PM

Quote:

Quote:

No one has answered how production cars with numerous electronic devices rely on the "terrible" floor pan/unibody to attach ALL the grounds in the entire vehicle. This remains the same regardless of where the battery is located. There is a heck a lot of surface area in a unibody. I do agree if the car is a rust bucket the unibody spot welds could possibly be an issue. If its so bad that the majority of the spot welds are suspect there is a way bigger issue than the ground path. When my car was completed I voltage drop tested my ground side under load. There was .2 volts drop at 28 amp draw from the center ground post of the battery to the ground wire of the dual cooling fans. The battery is grounded to a 3/8" stud welded to the cage with 1awg cable. The block/trans is also grounded with 1awg cable Doug


I think you are missing the point on race cars, it's not a voltage drop issue. it is a noise issue and old analog ignitions may never have a problem. but with new digital race ignitions it is an issue.




There are on board computers on all the new cars..
multiple ones in some cases... they are really touchy
with noise
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/08/15 06:33 PM

Quote:

Quote:

Quote:

No one has answered how production cars with numerous electronic devices rely on the "terrible" floor pan/unibody to attach ALL the grounds in the entire vehicle. This remains the same regardless of where the battery is located. There is a heck a lot of surface area in a unibody. I do agree if the car is a rust bucket the unibody spot welds could possibly be an issue. If its so bad that the majority of the spot welds are suspect there is a way bigger issue than the ground path. When my car was completed I voltage drop tested my ground side under load. There was .2 volts drop at 28 amp draw from the center ground post of the battery to the ground wire of the dual cooling fans. The battery is grounded to a 3/8" stud welded to the cage with 1awg cable. The block/trans is also grounded with 1awg cable Doug


I think you are missing the point on race cars, it's not a voltage drop issue. it is a noise issue and old analog ignitions may never have a problem. but with new digital race ignitions it is an issue.




There are on board computers on all the new cars..
multiple ones in some cases... they are really touchy
with noise



i bet they are not anywhere as sensitive as race ignitions. and how many different filters are they using? how confined are they?
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/08/15 06:38 PM

Quote:

Quote:

I am not sure I agree, I would rather have one reliable, properly sized, tested/measured ground, then, unless in an in an emergency, a random selection of undersized, maybe good grounds, and let the electrical devices figure which one is best. IE, if a ground is thought to be not correct, then any additional backup grounds have to all be the same proper size, thinking you can "share" or combine grounds is unwise and asking for future problems.

"static straps", are primarily for grounding static charges, not grounds.





My point was not to have a bunch of undersize grounds. My point was its nothing wrong with adding a ground of the correct size even if you already have a ground of the correct size in whatever circuit you are working with. Hence the saying .....you can never have to many grounds. Ron




I believe I understand your overall point, but the problem I see is when one has multiple grounds, often for extra assurance/back-up/whatever, unless they are all sized for the largest possible current demand, when one of the redundant grounds becomes less effective (corrosion, intermittent, loose, disconnected in error, etc), the current will then seek another ground with less resistance, and IF that ground is undersize, issues arise. Therefore My concept is just to have a single "great" ground path, and if a problem with that ground arises, the effect is immediate and maybe very obvious, and likely in a single location. That's why having a "lot" of grounds is not a goal for me.
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/08/15 06:41 PM

bet they are not anywhere as sensitive as race ignitions. and how many different filters are they using? how confined are they?




I dont know about the filters but its the low voltage
stuff that your trying to protect.. your dealing
with 0-5 volts or even 0-2 volts and the auto companies
run the grounds as said above... are they keeping it
clean with filters or not.. I dont know... I know
I had to deal with millivolt stuff on the fuel tank
(mainly the filler tube when it was plastic)
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/08/15 06:45 PM

Quote:

bet they are not anywhere as sensitive as race ignitions. and how many different filters are they using? how confined are they?




I dont know about the filters but its the low voltage
stuff that your trying to protect.. your dealing
with 0-5 volts or even 0-2 volts and the auto companies
run the grounds as said above... are they keeping it
clean with filters or not.. I dont know... I know
I had to deal with millivolt stuff on the fuel tank
(mainly the filler tube when it was plastic)



there you have it, that why you can't compare a pass vehicle with a race car.
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/08/15 08:01 PM

Noise can be a problem on any EFI car, but you add noise to the incredible cylinder pressure that you have in some of these cars that make 3000+ HP and you have a SERIOUS issue.

This is a typical thing we see, especially on THIS site. Guys have always done things a certain way, it works OK and when something different is suggested, they attempt to shoot that theory full of holes. Just because you have always done something a certain way, does not make it the right way for EVERY car out there.

I changed the way I wired cars, because I DID have issues on some high HP EFI cars with intermittent noise. So common sense tells you that if the changes were BETTER for EFI cars, they were better in general. At least that's how I looked at it, plus to me the "floating ground" deal is clean and easy. So what you have to string a couple extra wires. It makes trouble shooting SO much easier, because things are contained in a specific area.

As far as factory cars........who cares......I don't, because we are not talking about factory cars. Plus, when I worked for Dodge, I know our ECUs were directly battery grounded. Are they still??.........don't know, don't care.

So, you want to ground your whole car through the chassis or sheetmetal...........fine, no problem, but no need to try and prove it's the ONLY way or best way to do it

Oh yeah, forgot something and this is FACT not here say. The Holley Dominator ECU is capable of running factory LS coils. Millions of cars out there with LS coils. However, in a HIGH hp application, with high cylinder pressures, the "flyback" voltage from the LS coild was horrendous. Bad enough in fact, that we had to put a stupid amount of filtering in our boxes to keep the junky coils from smoking our boxes. So the point......what the factory cars have don't mean squat in a race car

Monte
Posted By: gregsdart

Re: Grounding for battery in the trunck? - 01/08/15 08:19 PM

Monte, thanks for making those points. It occurred to me that if I don't want to run a huge ground all the way to the battery in the trunk, then I should at least ground the critical components on their own circuit all the way to the battery with a properly sized ground wire for the load, and totally isolated from the starter.
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/08/15 08:25 PM

Quote:

Quote:

The most electrically conductive element is silver, followed by copper and gold. Silver also has the highest thermal conductivity of any element and the highest light reflectance. Although it is the best conductor, copper and gold are used more often in electrical applications because copper is less expensive and gold has a much higher corrosion resistance.




http://chemistry.about.com/od/elements/f/What-Is-The-Most-Conductive-Element.htm

.



I wonder where this Professor got or decided to make this statemnet, I was taught in the 1970s/1980 in basic elctricity and electronic college classes that gold was best for conductivity and silver and copper where down the ladder 3 or 4 from gold I wonder what changed
Not trying to hijack, clarification sometimes helps, sometimes hinders
My main message is the path of electron flow from the battery is out the negative side of the battery so that side, path, is really important to get right
Posted By: Thumperdart

Re: Grounding for battery in the trunck? - 01/08/15 08:33 PM

Just had a thought.............What if I ran a smaller gauge wire directly from my trunk mounted batts along the frame w/the fuel line for example BUT like factory cars, had it attached along the frame say every 2' or so............
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/08/15 08:53 PM

Quote:

Just had a thought.............What if I ran a smaller gauge wire directly from my trunk mounted batts along the frame w/the fuel line for example BUT like factory cars, had it attached along the frame say every 2' or so............




Monte is talking about ISOLATED ground.. totally separate
from the main ground... the ONLY place that they are
common is at the battery itself... the battery acts
as a filter and takes spikes and what not out of it
Posted By: RobX4406

Re: Grounding for battery in the trunck? - 01/08/15 09:15 PM

Quote:

Quote:

Quote:

The most electrically conductive element is silver, followed by copper and gold. Silver also has the highest thermal conductivity of any element and the highest light reflectance. Although it is the best conductor, copper and gold are used more often in electrical applications because copper is less expensive and gold has a much higher corrosion resistance.




http://chemistry.about.com/od/elements/f/What-Is-The-Most-Conductive-Element.htm

.



I wonder where this Professor got or decided to make this statemnet, I was taught in the 1970s/1980 in basic elctricity and electronic college classes that gold was best for conductivity and silver and copper where down the ladder 3 or 4 from gold I wonder what changed
Not trying to hijack, clarification sometimes helps, sometimes hinders
My main message is the path of electron flow from the battery is out the negative side of the battery so that side, path, is really important to get right




Another from a manufacturer
http://www.tibtech.com/conductivity.php
Posted By: Duner

Re: Grounding for battery in the trunck? - 01/08/15 09:20 PM

So if I am running an isolated/floating ground for the EFI portion - I'd imagine that the wire size vs load requirement would be downsized quite a bit when compared to the wire size / load requirement for the starter, lights, pumps and fans.

I'm thinking I could get by with a #6 wire for the isolated/floating ground portion, then go with an 00 run up to the starter/chassis itself. All sensors and the standalone computer get their own dedicated grounds running to the bus bar isolated/floating ground.

Does that sound right?

The only place I see a conflict is with the crank and cam sensors. Won't they see both grounds just thru contact? And can that negate the "floating" part anyway?
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/08/15 09:31 PM

Quote:

So if I am running an isolated/floating ground for the EFI portion - I'd imagine that the wire size vs load requirement would be downsized quite a bit when compared to the wire size / load requirement for the starter, lights, pumps and fans.

I'm thinking I could get by with a #6 wire for the isolated/floating ground portion, then go with an 00 run up to the starter/chassis itself. All sensors and the standalone computer get their own dedicated grounds running to the bus bar isolated/floating ground.

Does that sound right?

The only place I see a conflict is with the crank and cam sensors. Won't they see both grounds just thru contact? And can that negate the "floating" part anyway?




I would think your right with the wire size.. as
for the crank and cam I dont know.. maybe Monte will
tell you
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/08/15 09:34 PM



Are sensors powered hall effect, or two wire, or?
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/08/15 09:35 PM

I have been fighting issues like Monty talks about. My stuff is grounded to the battery and I still fight it.
Once you get agressive with the tune (over 20 psi of boost in my case) the plugs are hard to light. And that energy will go somewhere when the plug stops firing.
I'm still trying to figure it out lol
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/08/15 09:52 PM

Quote:



Are sensors powered hall effect, or two wire, or?




One thing I dont know is... since the battery is a
filter... the flow goes from neg to pos and we are
trying to isolate the neg... HOW far up the neg is
the battery still acting as a filter... maybe this
is what our issue is.. just guessing.. I dont know
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/08/15 10:04 PM

Quote:

I have been fighting issues like Monty talks about. My stuff is grounded to the battery and I still fight it.
Once you get agressive with the tune (over 20 psi of boost in my case) the plugs are hard to light. And that energy will go somewhere when the plug stops firing.
I'm still trying to figure it out lol


What plug wires do you have?

Monte
Posted By: 383man

Re: Grounding for battery in the trunck? - 01/08/15 10:34 PM

Quote:

Quote:

Quote:

I am not sure I agree, I would rather have one reliable, properly sized, tested/measured ground, then, unless in an in an emergency, a random selection of undersized, maybe good grounds, and let the electrical devices figure which one is best. IE, if a ground is thought to be not correct, then any additional backup grounds have to all be the same proper size, thinking you can "share" or combine grounds is unwise and asking for future problems.

"static straps", are primarily for grounding static charges, not grounds.





My point was not to have a bunch of undersize grounds. My point was its nothing wrong with adding a ground of the correct size even if you already have a ground of the correct size in whatever circuit you are working with. Hence the saying .....you can never have to many grounds. Ron




I believe I understand your overall point, but the problem I see is when one has multiple grounds, often for extra assurance/back-up/whatever, unless they are all sized for the largest possible current demand, when one of the redundant grounds becomes less effective (corrosion, intermittent, loose, disconnected in error, etc), the current will then seek another ground with less resistance, and IF that ground is undersize, issues arise. Therefore My concept is just to have a single "great" ground path, and if a problem with that ground arises, the effect is immediate and maybe very obvious, and likely in a single location. That's why having a "lot" of grounds is not a goal for me.




I understand your point also. I guess what I like about having a second proper ground is I kinda look at it like back-up. Like an eng to body ground. If for some reason one is left unhooked or the bolts left loose then with a back-up ground everything will still work. And if both are done right and working with good clean connections even better. Not saying do it as a bandaid just that it cant hurt. I dealt with alot of body ground problems over the years working at the Dodge dealer where even with a good looking tight connection you could only find the problem doing a voltage drop test. We had problems with Dodge Vans doing some weird things and finding grounds through the strange places causing some trans and wheel bearing problems so I always made an additional ground and put it on them myself after cleaning the factory ground. Ron
Posted By: 383man

Re: Grounding for battery in the trunck? - 01/08/15 10:40 PM

You know with the digital race ignitions and all the electronics on race cars its easy to understand about having good proper grounds.

I would say its why MSD tells you to ground the ground and put the red power wires on their units right to the battery. I see alot where guys dont do that and some get away with it but there is a reason they want the main ground and power wires put right to the battery. Ron
Posted By: Airwoofer

Re: Grounding for battery in the trunck? - 01/08/15 10:49 PM

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte




So Monte, are you saying that the only stuff that is critical to have the floating ground is the electronic stuff and not necessarily the rest of the analog stuff like starter, lights, fan, water pump, etc...? That's a whole lot easier to swallow than a complete rewire of a car to add EFI. Them wires under the dash are hard to get to on my junk, and the dash isn't coming out without cutting bars.

Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/09/15 02:41 AM

Quote:

Quote:

I have been fighting issues like Monty talks about. My stuff is grounded to the battery and I still fight it.
Once you get agressive with the tune (over 20 psi of boost in my case) the plugs are hard to light. And that energy will go somewhere when the plug stops firing.
I'm still trying to figure it out lol


What plug wires do you have?


Monte




The 409 Taylor's. Plan on switching to fire core this spring.
I was running Autolites and new plugs helped some. So now I have NGK plugs but waiting on March to see if there a little better.
Posted By: slammedR/T

Re: Grounding for battery in the trunck? - 01/09/15 04:25 AM

Mont is right, in factory efi vehicles the modules all have a seperate ground going to the battery. They are joined to gether with a splice comb. the body/frame is grounded and the starter and engine and fan motors, etc.. use frame/body grounds. On computer data lines they are ALL twisted pair and on the newer CAN bus sytems the ecm and bcm(some times the ebcm) will have a 120 ohm resistor in both modules, these resistors make the the data lines have even less noise. Also a sensor ground is not a standard ground, it will have an inline transistor to remove noise and it is a "higher ground threshhold" than a normal ground. Then when you get into 5v referenced systems and double redundant 5v reference systems your head starts to spin LOL!
Posted By: Duner

Re: Grounding for battery in the trunck? - 01/09/15 04:36 AM

I'm sharing my 5v referenced sensors with both the factory PCM and the MS3X - with power and grounds supplied by MS3X. I'm betting my noisy TPS signal is from the sharing somehow. How the heck do I clear it up?
Posted By: slammedR/T

Re: Grounding for battery in the trunck? - 01/09/15 04:46 AM

Quote:

I'm sharing my 5v referenced sensors with both the factory PCM and the MS3X - with power and grounds supplied by MS3X. I'm betting my noisy TPS signal is from the sharing somehow. How the heck do I clear it up?




I would do a ground bus, with the bus ground feed striaght to the bettery. Only have sensors grounded on the bus.
Posted By: Duner

Re: Grounding for battery in the trunck? - 01/09/15 04:55 AM

Quote:

Quote:

I'm sharing my 5v referenced sensors with both the factory PCM and the MS3X - with power and grounds supplied by MS3X. I'm betting my noisy TPS signal is from the sharing somehow. How the heck do I clear it up?




I would do a ground bus, with the bus ground feed striaght to the bettery. Only have sensors grounded on the bus.




I will be switching to rear mount battery this weekend. Simple enough to just run a #4 lead for the sensor grounds.
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/09/15 05:19 AM

Quote:

Noise can be a problem on any EFI car, but you add noise to the incredible cylinder pressure that you have in some of these cars that make 3000+ HP and you have a SERIOUS issue.

This is a typical thing we see, especially on THIS site. Guys have always done things a certain way, it works OK and when something different is suggested, they attempt to shoot that theory full of holes. Just because you have always done something a certain way, does not make it the right way for EVERY car out there.

I changed the way I wired cars, because I DID have issues on some high HP EFI cars with intermittent noise. So common sense tells you that if the changes were BETTER for EFI cars, they were better in general. At least that's how I looked at it, plus to me the "floating ground" deal is clean and easy. So what you have to string a couple extra wires. It makes trouble shooting SO much easier, because things are contained in a specific area.

As far as factory cars........who cares......I don't, because we are not talking about factory cars. Plus, when I worked for Dodge, I know our ECUs were directly battery grounded. Are they still??.........don't know, don't care.

So, you want to ground your whole car through the chassis or sheetmetal...........fine, no problem, but no need to try and prove it's the ONLY way or best way to do it

Oh yeah, forgot something and this is FACT not here say. The Holley Dominator ECU is capable of running factory LS coils. Millions of cars out there with LS coils. However, in a HIGH hp application, with high cylinder pressures, the "flyback" voltage from the LS coild was horrendous. Bad enough in fact, that we had to put a stupid amount of filtering in our boxes to keep the junky coils from smoking our boxes. So the point......what the factory cars have don't mean squat in a race car

Monte



Monte as much as I respect your knowledge sometimes I have to disagree. So the fact that a race car has more cylinder pressure make the injectors need a floating ground? Really? I agree that cylinder pressure could be an issue with spark. But what in the heck does cylinder pressure have to do with injector firing or coil triggering? Nothing that I can think of. I will go tomorrow and get some straight facts and report back. If I'm incorrect I will post that as well. The bottom line is that every electrical circuit needs correct sizing. Clean tight connections. And correct routing . We fight noise issues all the time. Fixes involve different routing, shielding and yes moving the feed or ground circuit to a different power or ground location. But saying "grounding at the frame/cage" (which was the original question in this post) won't work is a catch all, and I believe incorrect.
Doug
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/09/15 05:22 AM

Quote:

Quote:

Quote:

Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte




So Monte, are you saying that the only stuff that is critical to have the floating ground is the electronic stuff and not necessarily the rest of the analog stuff like starter, lights, fan, water pump, etc...? That's a whole lot easier to swallow than a complete rewire of a car to add EFI. Them wires under the dash are hard to get to on my junk, and the dash isn't coming out without cutting bars.




You are asking for a MAJOR headache with what you want to do...........and if I recall correctly, is the EXACT reason that I am not wiring your car for you. I told that I WOULD NOT do it, unless you let me rip all that stock crap out and wire the car RIGHT and you were NOT on board with that. You are asking for a MAJOR headache. Been there, done that and won't do it again. We have HAD this conversation standing in my shop. I refuse to chase gremlins on a car with a modern EFI and 40 year old factory wiring. Not worth it

Monte
Posted By: fourgearsavoy

Re: Grounding for battery in the trunck? - 01/09/15 05:23 AM

Quote:

bet they are not anywhere as sensitive as race ignitions. and how many different filters are they using? how confined are they?




I dont know about the filters but its the low voltage
stuff that your trying to protect.. your dealing
with 0-5 volts or even 0-2 volts and the auto companies
run the grounds as said above... are they keeping it
clean with filters or not.. I dont know... I know
I had to deal with millivolt stuff on the fuel tank
(mainly the filler tube when it was plastic)




That is the way Toyota/Lexus vehicles get away with grounding most of their 20-30 separate ECU's to the sheet metal. Most of the sensing circuits operate on a 5 volt reference signal so a sheet metal body ground on even the most sensitive systems is adequate. I'm kinda ground crazy on all my components on the Savoy I run ground points all over and most all of them can be traced back to my ground strap from the battery.
All that being said I still ground my battery to the bar in the trunk

Gus

Attached picture 8390090-moriaburnout.JPG
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/09/15 05:26 AM

Quote:

Quote:

Quote:

I have been fighting issues like Monty talks about. My stuff is grounded to the battery and I still fight it.
Once you get agressive with the tune (over 20 psi of boost in my case) the plugs are hard to light. And that energy will go somewhere when the plug stops firing.
I'm still trying to figure it out lol


What plug wires do you have?


Monte




The 409 Taylor's. Plan on switching to fire core this spring.
I was running Autolites and new plugs helped some. So now I have NGK plugs but waiting on March to see if there a little better.


The Taylors and the Moroso blue wires are notoriously bad for EMI noise. The Firecores are an excellent choice for an EFI car. I seldom "drink the koolaid" on that type stuff........but they flat work.......period.

Monte
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/09/15 07:45 AM

Thanks for the help!
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/10/15 03:38 AM

I said I would report back what I found out about grounds. First I will say that I have NO experience in running cars anywhere near the power level of Montes stuff. I will also admit I'm not a degreed electrical engineer. I do work with car electrics on prototype and production vehicles everyday. I sought out 3 very knowledgeable electrical engineers that design and work on modern electrical vehicle systems. These guys are not racers but are extremely knowledgeable if the field of electronics. Two of them of the saw absolutely no need for a separate ground cable from the battery to a forward location in the car. The third saw the only possible advantage would be to run a separate cable from the battery to the cylinder heads themselves. His theory was that enough current was being sent through a "race type coil" that it was possible that the spark plug current might possibly corrupt the ground side. Though he thought the possibility was very slight. He also stated that any possible advantage would be lost unless this cable was routed and used for cylinder head grounding (and obviously the starter) only. Everyone agreed on a few things.
#1 Grounds should be as close as short as possible.
#2 Grounds should not be stacked more than a few. But should all be as close together as possible. Such as having multiple ground studs with-in a small area.
#3 The mass of the uni-body/roll cage is more than adequate as a ground plane.
#4 The use of a thermal grease such as Alonox on connections, especially where wiring is bolted to aluminum. This will reduce the likelihood of fretting and heat damage due to thermal expansion and contraction of aluminum.
#5 That cylinder head grounding to the chassis may have the most potential of anything that has been discussed here. The possibility of plating on head studs/bolts may inhibit good grounding of the spark plug, though they have yet to see it in the field.
#6 Do not run any high current cables near sensor or pickup wiring.
Make sure sensor wiring pairs are twisted to cancel magnetic field effects in the harness. A shielded wire as part of that harness with a foil covering grounded at the module end only will act as a capacitor helping disperse noise.

Finally everyone agreed that testing voltage drop on individual circuits under loaded conditions will tell the story if the ground is adequate. Although this could be accurately done with an Oscilloscope acceptable results could be taken with a Fluke meter. The min/max selection will take samples of voltage drop at .01 second while recording.
I hope everyone can gain some insight from this. While I don't think a dedicated ground would hurt, I don't think it is necessary either. In my world budget is paramount. With 25' of #1 cable going for close to $100 that is an area where my dollars might be spent wisely elsewhere.
Doug
Posted By: fourgearsavoy

Re: Grounding for battery in the trunck? - 01/10/15 03:51 AM

Wow! Thanks for the research Doug
Gus

Attached picture 8390968-rearviewsavoy.jpg
Posted By: slammedR/T

Re: Grounding for battery in the trunck? - 01/10/15 04:58 AM



spaghettimenders.com
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/10/15 05:05 AM

Quote:

I said I would report back what I found out about grounds. First I will say that I have NO experience in running cars anywhere near the power level of Montes stuff. I will also admit I'm not a degreed electrical engineer. I do work with car electrics on prototype and production vehicles everyday. I sought out 3 very knowledgeable electrical engineers that design and work on modern electrical vehicle systems. These guys are not racers but are extremely knowledgeable if the field of electronics. Two of them of the saw absolutely no need for a separate ground cable from the battery to a forward location in the car. The third saw the only possible advantage would be to run a separate cable from the battery to the cylinder heads themselves. His theory was that enough current was being sent through a "race type coil" that it was possible that the spark plug current might possibly corrupt the ground side. Though he thought the possibility was very slight. He also stated that any possible advantage would be lost unless this cable was routed and used for cylinder head grounding (and obviously the starter) only. Everyone agreed on a few things.
#1 Grounds should be as close as short as possible.
#2 Grounds should not be stacked more than a few. But should all be as close together as possible. Such as having multiple ground studs with-in a small area.
#3 The mass of the uni-body/roll cage is more than adequate as a ground plane.
#4 The use of a thermal grease such as Alonox on connections, especially where wiring is bolted to aluminum. This will reduce the likelihood of fretting and heat damage due to thermal expansion and contraction of aluminum.
#5 That cylinder head grounding to the chassis may have the most potential of anything that has been discussed here. The possibility of plating on head studs/bolts may inhibit good grounding of the spark plug, though they have yet to see it in the field.
#6 Do not run any high current cables near sensor or pickup wiring.
Make sure sensor wiring pairs are twisted to cancel magnetic field effects in the harness. A shielded wire as part of that harness with a foil covering grounded at the module end only will act as a capacitor helping disperse noise.

Finally everyone agreed that testing voltage drop on individual circuits under loaded conditions will tell the story if the ground is adequate. Although this could be accurately done with an Oscilloscope acceptable results could be taken with a Fluke meter. The min/max selection will take samples of voltage drop at .01 second while recording.
I hope everyone can gain some insight from this. While I don't think a dedicated ground would hurt, I don't think it is necessary either. In my world budget is paramount. With 25' of #1 cable going for close to $100 that is an area where my dollars might be spent wisely elsewhere.
Doug


Talked to a close friend of mine today ( Dick Headman - Headman headers ) who does a lot of EFI work worth "Fast Systems" and he echoed this thread. "Biggest problem is dirty connections and bundled wires". He recommends welding a ground stud (s) to the frame in a convenient area. He also mentioned grounding the rad ( especially aluminum radiators ) and individual aluminum head grounds. Alonox was also mentioned.
Posted By: DusterDave

Re: Grounding for battery in the trunck? - 01/10/15 05:12 AM

I'm thinking this thread should go into the Tech Archives at some point.
Posted By: RobX4406

Re: Grounding for battery in the trunck? - 01/10/15 05:13 AM

#1 at $4/ft?

Find a new supplier. There are plenty of places to get #1 battery cable for under $2/ft. Welding cable will come in at $3/ft or less.

I bought 2/0 battery cable for under $3/ft
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/10/15 05:39 AM

Quote:

#1 at $4/ft?

Find a new supplier. There are plenty of places to get #1 battery cable for under $2/ft. Welding cable will come in at $3/ft or less.

I bought 2/0 battery cable for under $3/ft



When writing the response I just did a quick price check off the internet to get an idea.
Doug
Posted By: RobX4406

Re: Grounding for battery in the trunck? - 01/10/15 05:49 AM

Quote:

Quote:

#1 at $4/ft?

Find a new supplier. There are plenty of places to get #1 battery cable for under $2/ft. Welding cable will come in at $3/ft or less.

I bought 2/0 battery cable for under $3/ft



When writing the response I just did a quick price check off the internet to get an idea.
Doug




Waytek and del city have pretty good pricing on cable. Del City is really nice if you buy $100, get free shipping with a 20% off coupon. Stuff gets heavy.

All good.
Posted By: Skeptic

Re: Grounding for battery in the trunck? - 01/10/15 06:15 AM

Quote:



spaghettimenders.com


That look very much like I wired up my Barracuda
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/10/15 07:54 AM

I KNOW what works for ME and what is trouble free and THAT is what I will continue to do.....NOT interested in how factory street cars are wired. I have several outside I could look at if I wanted to know.......You guys can have it from here

Monte
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/10/15 11:12 AM

Quote:

I KNOW what works for ME and what is trouble free and THAT is what I will continue to do.....NOT interested in how factory street cars are wired. I have several outside I could look at if I wanted to know.......You guys can have it from here

Monte


Monte same here, I doubt you will ever find a professional race car shop that uses the chassis as a ground in any type car they wire. there is a reason for that. so if people want to use it, have at it. my arrow uses the chassis and it works but it is analog and if I ever rewire it and go digital I will do it right. again you can't compare a regular car to todays race cars with the ignitions and electronics being used in some.
Posted By: Dean_Kuzluzski

Re: Grounding for battery in the trunck? - 01/10/15 02:11 PM

Quote:

I KNOW what works for ME and what is trouble free and THAT is what I will continue to do.....NOT interested in how factory street cars are wired. I have several outside I could look at if I wanted to know.......You guys can have it from here

Monte




As a business owner and entrepreneur you have to protect your reputation........like when I talk to the painters I know, they grind out any old body filler and start with clean metal so nothing affects their work. Same with old wiring. Not an attack just an observation. And my previous post basically agrees with you.

I worked in an EMI lab years ago, with engineers on an on-call basis. We would wrap modules and wiring with aluminum foil to one-by-on eliminate noise during tests on a new vehicle program. That would get sent back to the harness or module supplier for update. These tests took days sometimes longer than a week. Inductive coupling was a major nuisance. There is theoretical science in electronics that cannot be determined, on the drawing board so to speak, to the "real world" level without actual testing. So just looking at a car in the parking lot and mimicking it is a pretty funny statement.

Production vehicles have had "Clean" grounds since, at least, the late 80's. Given the number of onboard computers in todays high option cars, new car builders/companies only have to protect what could be now in the billions in cost for warranty and then loss of future sales. Nothing to learn from there for sure. The average racer it could cost thousands in a final round.

Glad someone mentioned "twisted pair". Sensors leads tend to act as attennae for noise (depending on length vs frequency). Twisted pair shields that out and gives a cleaner signal to your module. We all want that.

And when I said the "Copper was best" it was from a cost perspective.
Posted By: moparx

Re: Grounding for battery in the trunck? - 01/10/15 03:34 PM

could a ground buss be made from a strip of 3/4w x 1/4t copper strip ? what bolts would you use to secure the lugs ? brass ?
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/10/15 03:47 PM

Quote:

Quote:

I KNOW what works for ME and what is trouble free and THAT is what I will continue to do.....NOT interested in how factory street cars are wired. I have several outside I could look at if I wanted to know.......You guys can have it from here

Monte




As a business owner and entrepreneur you have to protect your reputation........like when I talk to the painters I know, they grind out any old body filler and start with clean metal so nothing affects their work. Same with old wiring. Not an attack just an observation. And my previous post basically agrees with you.

I worked in an EMI lab years ago, with engineers on an on-call basis. We would wrap modules and wiring with aluminum foil to one-by-on eliminate noise during tests on a new vehicle program. That would get sent back to the harness or module supplier for update. These tests took days sometimes longer than a week. Inductive coupling was a major nuisance. There is theoretical science in electronics that cannot be determined, on the drawing board so to speak, to the "real world" level without actual testing. So just looking at a car in the parking lot and mimicking it is a pretty funny statement.

Production vehicles have had "Clean" grounds since, at least, the late 80's. Given the number of onboard computers in todays high option cars, new car builders/companies only have to protect what could be now in the billions in cost for warranty and then loss of future sales. Nothing to learn from there for sure. The average racer it could cost thousands in a final round.

Glad someone mentioned "twisted pair". Sensors leads tend to act as attennae for noise (depending on length vs frequency). Twisted pair shields that out and gives a cleaner signal to your module. We all want that.

And when I said the "Copper was best" it was from a cost perspective.




We work with our EMI lab on a daily basis. My observations came from very reliable people who work with vehicle systems daily. Additional they all felt that the frequency of circuits used in a racecar were not as difficult to control noise as higher frequency circuits such as radio, key fobs ,etc. If anyone thinks today's vehicles are thrown together with out a intense amount of testing they are sadly mistaken. Especially on the electrical end. Has anyone here ever tested a connection running Micro amps? I'll bet not. It's unbelievable the lengths they go to to test.
Doug
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/10/15 04:03 PM

Quote:

Quote:

I KNOW what works for ME and what is trouble free and THAT is what I will continue to do.....NOT interested in how factory street cars are wired. I have several outside I could look at if I wanted to know.......You guys can have it from here

Monte




As a business owner and entrepreneur you have to protect your reputation........like when I talk to the painters I know, they grind out any old body filler and start with clean metal so nothing affects their work. Same with old wiring. Not an attack just an observation. And my previous post basically agrees with you.

I worked in an EMI lab years ago, with engineers on an on-call basis. We would wrap modules and wiring with aluminum foil to one-by-on eliminate noise during tests on a new vehicle program. That would get sent back to the harness or module supplier for update. These tests took days sometimes longer than a week. Inductive coupling was a major nuisance. There is theoretical science in electronics that cannot be determined, on the drawing board so to speak, to the "real world" level without actual testing. So just looking at a car in the parking lot and mimicking it is a pretty funny statement.

Production vehicles have had "Clean" grounds since, at least, the late 80's. Given the number of onboard computers in todays high option cars, new car builders/companies only have to protect what could be now in the billions in cost for warranty and then loss of future sales. Nothing to learn from there for sure. The average racer it could cost thousands in a final round.

Glad someone mentioned "twisted pair". Sensors leads tend to act as attennae for noise (depending on length vs frequency). Twisted pair shields that out and gives a cleaner signal to your module. We all want that.

And when I said the "Copper was best" it was from a cost perspective.


Never ending argument regarding what applications have the most sensitive electronic packages ( race cares or street cars ). Street cars Shirley have more of it. As far as comparing warrantee costs to last round wins - You're kidding right??? Technology goes both ways regarding racing applications and street applications. "Experts" on both sides of that fence - fighting the same gremlins. I'm open to seeing both side of this argument. In the end, everyone has to make up their own minds on how they want to do ( wire) their stuff. I learned some stuff and will probably be redoing some wiring on my race car. ( I will continue to use the frame as a ground - works for me ). I am in the process of doing a complete wiring job on another project of mine. Starting from scratch. It will be carbureted at first, but will probably go to an EFI system in the future. This thread will be helpful in that regard. Although I am not the OP,thanks to all that contributed.

Attached picture 8391330-33kiddiecar.jpg
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/10/15 06:04 PM

The thing about THIS site in particular, is that experience with something is of little to no use. Because when you say something that others don't agree with, they are going to search out enough "experts" to debunk your input and say "see, I told you".

Just like all this talk about factory cars........I DON'T care. We are not talking about factory cars.

What I DO know, is that EFI race cars with high HP applications are VERY sensitive to noise and how they are wired. I found this out by having serious issues with a customers car and searching out some help to solve that problem. Rewiring the car with the "floating" ground system FIXED that car. I have since wired several other cars with that system and had ZERO problems. I guess I could have "argued" with the guy that told me to do that and tried to shoot his theory all full of holes..........but instead, I noticed that he had a LOT of really fast cars out there that he had wired up. "Hey, this guy must know something" was my thoughts........he did.

Bottom line, I was only trying to pass on some information that worked for me, NOT get in a theoretical debate. So guys just need to do what they want or are comfortable with..........because it really doesn't matter to me

Monte
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/10/15 06:07 PM

"#6 .... A shielded wire as part of that harness with a foil covering grounded at the module end only will act as a capacitor helping disperse noise."

This is a new sub topic. Just want to be clear here on what the 3? knowledgeable engineers meant.

Are we saying connecting shields at the "module end" is to be discouraged, or that both ends is better, or only connect at the power source end for grounding the shield?

Do we mean by "disperse", to reduce in effect, or to send to other devices with a negative result?

Revision:
OK, the first question I asked above I should know is kinda dumb, since we are talking "sensor shields", and grounding at one end is a given standard. Maybe my first thought was really, ground the shield at the module, or take it all the way to the the "floating central ground, and then kinda answer my next question about disperse, which I thinking everybody but me understands to mean dissipate the noise issue.
Posted By: MattW

Re: Grounding for battery in the trunck? - 01/10/15 06:28 PM

Quote:

The thing about THIS site in particular, is that experience with something is of little to no use. Because when you say something that others don't agree with, they are going to search out enough "experts" to debunk your input and say "see, I told you".

Just like all this talk about factory cars........I DON'T care. We are not talking about factory cars.

What I DO know, is that EFI race cars with high HP applications are VERY sensitive to noise and how they are wired. I found this out by having serious issues with a customers car and searching out some help to solve that problem. Rewiring the car with the "floating" ground system FIXED that car. I have since wired several other cars with that system and had ZERO problems. I guess I could have "argued" with the guy that told me to do that and tried to shoot his theory all full of holes..........but instead, I noticed that he had a LOT of really fast cars out there that he had wired up. "Hey, this guy must know something" was my thoughts........he did.

Bottom line, I was only trying to pass on some information that worked for me, NOT get in a theoretical debate. So guys just need to do what they want or are comfortable with..........because it really doesn't matter to me

Monte





Hey Monte at least this ones better than the Pinion Angle, LBA, 8 3/4 etc.... debate!
Keep posting as they will too. Its up to the individual to try what works best for them. At least we have option and that is always good
Posted By: lockjaw-express

Re: Grounding for battery in the trunk? - 01/10/15 06:34 PM

Monte, is correct on what he has posted...also, Current flows from Negative to Positive. So, the Grounding is just as important as anything else in a circuit.

Another point, are ground loops. So, the best way to connect grounds are from a central point, and "crow Foot" out from that point.

Also, It never occurred to me about the bonding/ground jumper from the heads to the main ground...great point, since hi-voltage (RF) would be bled back to the chassis/ground/battery.

The Battery is a power source, but also a great filter capacitor for all kinds of noise.

BTW, I am a BSEE, and I have learned a few things from you all!

Mark
Posted By: gregsdart

Re: Grounding for battery in the trunck? - 01/10/15 06:45 PM

I was told ground only one end of the foil sheath. If you ground both ends, it becomes a receiver.
Posted By: gregsdart

Re: Grounding for battery in the trunck? - 01/10/15 06:48 PM

Question for Monte= At what point did you start to experience trouble with different types of plug wires? I run a digital seven MSD unit, alky,(actually M5, which has about 5 percent nitroparafins in it) .027 gap, 15/1 compression, Blue Max wires.
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/10/15 07:12 PM

Quote:

Question for Monte= At what point did you start to experience trouble with different types of plug wires? I run a digital seven MSD unit, alky,(actually M5, which has about 5 percent nitroparafins in it) .027 gap, 15/1 compression, Blue Max wires.


You will PROBABLY never have a problem on a car with carbs and a standard ignition. Again, EFI cars is where we see it......................And you tell somebody that and you get the "well, every Pro-Stocker I have ever seen has Moroso wires".............well so what, we are NOT building a damn Pro-Stocker. We have a twin turbo big block, making 3500hp. What do wires on a Pro-Stocker have to with that. Everybody wants to relate to something other than what they are doing................But see, HERE is where I generally do things different. When I learn something, I try to APPLY that knowledge. Now when I see that a certain wire causes problems on an EFI car, I won't put it on ANY car, why would I. Problems on any combo, tells me that wire is not as good as another wire, and COULD potentially cause an issue with electronics, so why use the inferior product, even though it seems to "work good enough" on some cars. Just like this whole damn thread about wiring. I KNOW FOR A FACT, the "floating ground" has worked better for me and solved some issues. That alone, tells me that it is better, regardless of the application, so why not use it and avoid a problem BEFORE you have it. If you only do what you have ALWAYS done, or what was "good enough" you will NEVER be better............I always strive to be BETTER.

I understand money and budgets............but a LOT of this stuff just simply boils down to guys wanting to do it "cheap and easy"

Monte
Posted By: Jeremiah

Re: Grounding for battery in the trunck? - 01/10/15 07:58 PM

Lots of great information in this thread. Doug thank you for sharing the opinion of the engineers from your work place. That is good food for thought. And Monte we all appreciate you wealth of knowledge and I understand what you are saying concerning applied knowledge vs. theoretical. In my line of work we call is "paralysis by analysis". I am famous in my group for fixing stuff "by ear" and having everything back up and running before the other guys finds the right page in the manual. Lol not to say that hasn't bit me in the butt a few times but live and learn. I stopped in shop sr. on the way to the house last night and took a quick peak at my red charger mentioned early on in this thread. It has the following:

1) Ground lead from passenger head to firewall
2) Ground lead from driver head to k-member
3) Floating ground tied to firewall and d/s frame rail
(this is where all of the MSD, 2-step, tach, etc. ground land)
4) Battery is grounded to stud on p/s rear frame rail
5) Battery + is landed on the starter relay stud. All 12V+ is fed from this point. The alternator also lands here to partially bypass the ammeter.

*frame connectors are welded in*

I know it's not a mega dollar EFI deal and not even a race car but it does get miles and abuse making a good test bed. My point in saying all of this is that even though I have the battery grounded "locally" the car does use all of the other methods that you mentioned. I feel that there is validity in both sides. It's better to design a clean, well thought out system than to chase your tail finding gremlins along the way. Thanks again to all contributors. We are working on rewiring the black Charger and this is a great thread to get the creative juices flowing.
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/10/15 08:14 PM

Quote:

The thing about THIS site in particular, is that experience with something is of little to no use. Because when you say something that others don't agree with, they are going to search out enough "experts" to debunk your input and say "see, I told you".

Just like all this talk about factory cars........I DON'T care. We are not talking about factory cars.

What I DO know, is that EFI race cars with high HP applications are VERY sensitive to noise and how they are wired. I found this out by having serious issues with a customers car and searching out some help to solve that problem. Rewiring the car with the "floating" ground system FIXED that car. I have since wired several other cars with that system and had ZERO problems. I guess I could have "argued" with the guy that told me to do that and tried to shoot his theory all full of holes..........but instead, I noticed that he had a LOT of really fast cars out there that he had wired up. "Hey, this guy must know something" was my thoughts........he did.

Bottom line, I was only trying to pass on some information that worked for me, NOT get in a theoretical debate. So guys just need to do what they want or are comfortable with..........because it really doesn't matter to me

Monte



I'm not disputing that your fix repaired your issues. I guess I'm coming off wrong. We both agreed that the roll cage works in many instances. My digging was to find out why your method overcame the issue. So far I haven't been able to understand why it worked, which obviously it has. There are different methods to diagnose a problem. Use scientific knowledge or try things and see what works. Both have their merits. Many times there is no choice. We just have to work it out and see what happens. What I think is beneficial is learning how all systems function. Hopefully this discussion has done that. I'm still curious. If I knew why your method fixed your issue I might be able to use that knowledge to repair a future problem. I didn't mean to seem argumentative, just trying to learn.
Doug
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/10/15 08:14 PM

Guys also forget every car is different.
I have been EFI since the 90's. My Valiant has hundreds of runs on it. I try'd to use most of the stuff I knew worked on that car for my new turbo car. Bottom line is I had trouble last year fighting issues that only showed up in the upper RPM making 20 psi of boost or more. I ran grounds everywhere. From heads to battery, From relays to battery, From frame to battery.
you name it I changed it. And only made very small improvements. So when Monty suggests something in a post like this I will take his advice and make the recommended changes and try again
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/11/15 03:39 AM

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Question for Monte= At what point did you start to experience trouble with different types of plug wires? I run a digital seven MSD unit, alky,(actually M5, which has about 5 percent nitroparafins in it) .027 gap, 15/1 compression, Blue Max wires.


You will PROBABLY never have a problem on a car with carbs and a standard ignition. Again, EFI cars is where we see it......................And you tell somebody that and you get the "well, every Pro-Stocker I have ever seen has Moroso wires".............well so what, we are NOT building a damn Pro-Stocker. We have a twin turbo big block, making 3500hp. What do wires on a Pro-Stocker have to with that. Everybody wants to relate to something other than what they are doing................But see, HERE is where I generally do things different. When I learn something, I try to APPLY that knowledge. Now when I see that a certain wire causes problems on an EFI car, I won't put it on ANY car, why would I. Problems on any combo, tells me that wire is not as good as another wire, and COULD potentially cause an issue with electronics, so why use the inferior product, even though it seems to "work good enough" on some cars. Just like this whole damn thread about wiring. I KNOW FOR A FACT, the "floating ground" has worked better for me and solved some issues. That alone, tells me that it is better, regardless of the application, so why not use it and avoid a problem BEFORE you have it. If you only do what you have ALWAYS done, or what was "good enough" you will NEVER be better............I always strive to be BETTER.

I understand money and budgets............but a LOT of this stuff just simply boils down to guys wanting to do it "cheap and easy"

Monte


You need to go back and read the OP's post - he is building a "street Dart" - long ways from a 3500HP what ever. Then you need to reread your first post to me. Maybe you won't have such a singular point of view on the subject. Not everything that DOESN'T work for you or on your application should automatically be classified as inferior to what you are using or doing!! Jeeeese!
Posted By: sunroofgtx

Re: Grounding for battery in the trunck? - 01/11/15 06:10 AM

This has been an excellent read. I've had to read some of the posts 3 or 4 times to get it to sink in. Excellent views.
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/11/15 06:40 AM

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Question for Monte= At what point did you start to experience trouble with different types of plug wires? I run a digital seven MSD unit, alky,(actually M5, which has about 5 percent nitroparafins in it) .027 gap, 15/1 compression, Blue Max wires.


You will PROBABLY never have a problem on a car with carbs and a standard ignition. Again, EFI cars is where we see it......................And you tell somebody that and you get the "well, every Pro-Stocker I have ever seen has Moroso wires".............well so what, we are NOT building a damn Pro-Stocker. We have a twin turbo big block, making 3500hp. What do wires on a Pro-Stocker have to with that. Everybody wants to relate to something other than what they are doing................But see, HERE is where I generally do things different. When I learn something, I try to APPLY that knowledge. Now when I see that a certain wire causes problems on an EFI car, I won't put it on ANY car, why would I. Problems on any combo, tells me that wire is not as good as another wire, and COULD potentially cause an issue with electronics, so why use the inferior product, even though it seems to "work good enough" on some cars. Just like this whole damn thread about wiring. I KNOW FOR A FACT, the "floating ground" has worked better for me and solved some issues. That alone, tells me that it is better, regardless of the application, so why not use it and avoid a problem BEFORE you have it. If you only do what you have ALWAYS done, or what was "good enough" you will NEVER be better............I always strive to be BETTER.

I understand money and budgets............but a LOT of this stuff just simply boils down to guys wanting to do it "cheap and easy"

Monte


You need to go back and read the OP's post - he is building a "street Dart" - long ways from a 3500HP what ever. Then you need to reread your first post to me. Maybe you won't have such a singular point of view on the subject. Not everything that DOESN'T work for you or on your application should automatically be classified as inferior to what you are using or doing!! Jeeeese!


Your right, how dare I give an opposing point of view to the "slap it on the frame and go, it's good enough" point of view. You're right, I'm wrong........happy??

Monte
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/11/15 07:21 AM

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The thing about THIS site in particular, is that experience with something is of little to no use. Because when you say something that others don't agree with, they are going to search out enough "experts" to debunk your input and say "see, I told you".

Just like all this talk about factory cars........I DON'T care. We are not talking about factory cars.

What I DO know, is that EFI race cars with high HP applications are VERY sensitive to noise and how they are wired. I found this out by having serious issues with a customers car and searching out some help to solve that problem. Rewiring the car with the "floating" ground system FIXED that car. I have since wired several other cars with that system and had ZERO problems. I guess I could have "argued" with the guy that told me to do that and tried to shoot his theory all full of holes..........but instead, I noticed that he had a LOT of really fast cars out there that he had wired up. "Hey, this guy must know something" was my thoughts........he did.

Bottom line, I was only trying to pass on some information that worked for me, NOT get in a theoretical debate. So guys just need to do what they want or are comfortable with..........because it really doesn't matter to me

Monte



I'm not disputing that your fix repaired your issues. I guess I'm coming off wrong. We both agreed that the roll cage works in many instances. My digging was to find out why your method overcame the issue. So far I haven't been able to understand why it worked, which obviously it has. There are different methods to diagnose a problem. Use scientific knowledge or try things and see what works. Both have their merits. Many times there is no choice. We just have to work it out and see what happens. What I think is beneficial is learning how all systems function. Hopefully this discussion has done that. I'm still curious. If I knew why your method fixed your issue I might be able to use that knowledge to repair a future problem. I didn't mean to seem argumentative, just trying to learn.
Doug


The answer is very easy actually. We know EMI noise is a very REAL issue, on normal and high HP applications. High HP cars have tremendous cylinder pressure, meaning VERY hard to light off. This taxes the ignition system VERY heavily. When that happens, you get spikes, flyback voltage and all sorts of other things that can wreck havoc on somewhat delicate sensors.

FastMop is talking about a high rpm miss when the boost gets up.....SOMETHING is noisy. Slammed R/T has a TPS issue........SOMETHING is noisy. If EVERYTHING on the car is grounded to one big ground circuit, the chassis, NOTHING is "clean". Ground the water or fuel pump, to the same stud where the ECU or ignition box is and you are ASKING to have a problem, even on a carbed car. Most take the ground circuit of their car for granted, when it is EASILY the MOST important electrical circuit on the whole damn car.

MrP and other tech are talking about ground issues, burning up wheel bearings and trans parts. How does that happen?.....backfeeds, spikes and other things from a poorly performing ground system is how. I had a customer fight a high speed miss in an IHRA Pro-Stocker for TWO years. Rewired the car a couple times, as well as replaced EVERY electrical part on it. Turned out, the chassis had become magnetized and was wrecking the ignition system at high rpm. Far fetched, YES, but it happened. So how did they fix it? "Floating ground" and took the chassis out of the equation. I didn't fix it or find it.....somebody MUCH smarter than me did, but what I DID do was pay attention to what he was telling me.

Just like I mentioned the "factory" LS coils earlier. They are regarded as very good "hotrod" coils and they are. There are millions of them on the road causing ZERO issues on factory cars. We had no problems with them either, when coupled with the Holley ECUs, until some turbo guys starting making SERIOUS boost. Our boxes have 5 times the filtering of a factory GM ECU, yet these guys were smoking our boxes right and left. We tested them at the plant and they were great until you put them in a REALLY high stress environment, ie HIGH cylinder pressure and then the "flyback" voltage became crazy high. Enough to smoke ECUs. So now our boxes have enough filtering to probably work on the damn space shuttle..........This was the reason I said earlier that I don't CARE how factory cars are wired, because it is NOT an apples to apples comparison. Some seem to forget, I work FOR Holley and have access to some very high tech testing equipment, procedures and data. I don't say this stuff just to hear myself talk, or because I THINK it's right. I have SEEN it. We have a chamber, that I can completely PUT THE FIRE OUT of an MSD 10 box, with pressure. If you could see what happens inside that cell, when we load a chamber that hard, some of this would be MUCH easier to understand

Monte
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 01/11/15 09:25 AM

So you would ground cylinder heads and ecu to the buss bar? My thinking is anything with an electric motor, fans,fuel pump,wipers,wp etc. should NOT be grounded to the buss bar?
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/11/15 03:12 PM

Quote:

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Quote:

The thing about THIS site in particular, is that experience with something is of little to no use. Because when you say something that others don't agree with, they are going to search out enough "experts" to debunk your input and say "see, I told you".

Just like all this talk about factory cars........I DON'T care. We are not talking about factory cars.

What I DO know, is that EFI race cars with high HP applications are VERY sensitive to noise and how they are wired. I found this out by having serious issues with a customers car and searching out some help to solve that problem. Rewiring the car with the "floating" ground system FIXED that car. I have since wired several other cars with that system and had ZERO problems. I guess I could have "argued" with the guy that told me to do that and tried to shoot his theory all full of holes..........but instead, I noticed that he had a LOT of really fast cars out there that he had wired up. "Hey, this guy must know something" was my thoughts........he did.

Bottom line, I was only trying to pass on some information that worked for me, NOT get in a theoretical debate. So guys just need to do what they want or are comfortable with..........because it really doesn't matter to me

Monte



I'm not disputing that your fix repaired your issues. I guess I'm coming off wrong. We both agreed that the roll cage works in many instances. My digging was to find out why your method overcame the issue. So far I haven't been able to understand why it worked, which obviously it has. There are different methods to diagnose a problem. Use scientific knowledge or try things and see what works. Both have their merits. Many times there is no choice. We just have to work it out and see what happens. What I think is beneficial is learning how all systems function. Hopefully this discussion has done that. I'm still curious. If I knew why your method fixed your issue I might be able to use that knowledge to repair a future problem. I didn't mean to seem argumentative, just trying to learn.
Doug


The answer is very easy actually. We know EMI noise is a very REAL issue, on normal and high HP applications. High HP cars have tremendous cylinder pressure, meaning VERY hard to light off. This taxes the ignition system VERY heavily. When that happens, you get spikes, flyback voltage and all sorts of other things that can wreck havoc on somewhat delicate sensors.

FastMop is talking about a high rpm miss when the boost gets up.....SOMETHING is noisy. Slammed R/T has a TPS issue........SOMETHING is noisy. If EVERYTHING on the car is grounded to one big ground circuit, the chassis, NOTHING is "clean". Ground the water or fuel pump, to the same stud where the ECU or ignition box is and you are ASKING to have a problem, even on a carbed car. Most take the ground circuit of their car for granted, when it is EASILY the MOST important electrical circuit on the whole damn car.

MrP and other tech are talking about ground issues, burning up wheel bearings and trans parts. How does that happen?.....backfeeds, spikes and other things from a poorly performing ground system is how. I had a customer fight a high speed miss in an IHRA Pro-Stocker for TWO years. Rewired the car a couple times, as well as replaced EVERY electrical part on it. Turned out, the chassis had become magnetized and was wrecking the ignition system at high rpm. Far fetched, YES, but it happened. So how did they fix it? "Floating ground" and took the chassis out of the equation. I didn't fix it or find it.....somebody MUCH smarter than me did, but what I DID do was pay attention to what he was telling me.

Just like I mentioned the "factory" LS coils earlier. They are regarded as very good "hotrod" coils and they are. There are millions of them on the road causing ZERO issues on factory cars. We had no problems with them either, when coupled with the Holley ECUs, until some turbo guys starting making SERIOUS boost. Our boxes have 5 times the filtering of a factory GM ECU, yet these guys were smoking our boxes right and left. We tested them at the plant and they were great until you put them in a REALLY high stress environment, ie HIGH cylinder pressure and then the "flyback" voltage became crazy high. Enough to smoke ECUs. So now our boxes have enough filtering to probably work on the damn space shuttle..........This was the reason I said earlier that I don't CARE how factory cars are wired, because it is NOT an apples to apples comparison. Some seem to forget, I work FOR Holley and have access to some very high tech testing equipment, procedures and data. I don't say this stuff just to hear myself talk, or because I THINK it's right. I have SEEN it. We have a chamber, that I can completely PUT THE FIRE OUT of an MSD 10 box, with pressure. If you could see what happens inside that cell, when we load a chamber that hard, some of this would be MUCH easier to understand

Monte



No, this is is exactly what I was looking for. I believe the sensors, TPS etc should have no issue if shielded. Now even with a factory coil the amount of energy your feeding it is WAY higher than the factory. For what it's worth we chased a FAST EFI on a 6.1 that would only run the firing order 1,8,4,3,1,8,4,3, etc. It turned out to be a magnetized cam basket. Even though the scope trace of the Cam sensor was perfectly normal.
In both cases it would be interesting to understand how either part became magnetized. My thought is that more amperage draw was causing the issue, but the starter draws more amps than an ignition box. Welding is another area where a lot of amperage has been fed through. (our cam basket had been welded). Now I'm wondering if it's not high voltage instead. From what I've learned flyback, magnetic noise, and electrical noise are three separate issues. I'll go back and discuss these issue's with my guys and report back.
Doug
Posted By: MattW

Re: Grounding for battery in the trunck? - 01/11/15 05:16 PM

I have SEEN it. We have a chamber, that I can completely PUT THE FIRE OUT of an MSD 10 box, with pressure. If you could see what happens inside that cell, when we load a chamber that hard, some of this would be MUCH easier to understand

Monte




This would be nice to see. Possible to get a video?
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/11/15 05:22 PM

Great web sight you have Monte. After spending some time watching them run at Vegas this year, I have a new found respect for the "Pro Mod" classes. When it comes to drag racing, chose guys ( and cars )are for sure in a league of their own. I am not too old to understand that there is no place for Chassis grounds in that arena.
Posted By: markz528

Re: Grounding for battery in the trunck? - 01/11/15 09:10 PM

All I know is that I run a MSD 7AL2 box. I wanted to see how much noise there was on the grounds from the box so I dug out my scope and Rogowski coil. Bet most people don't know what a Rogowski coil is - it is a flexible core current transducer. Mine has a bandwidth of 5 to 8 mhz so it is designed to measure high frequency current.

There was so much noise it was impossible to measure. I got no idea how any of the electronics works with all that noise....

That convinced me to follow MSD's installation instructions to a t!
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/11/15 09:23 PM

I burnt up the same fast box 3 times trying to figure out my issues. I could not figure out why it was frying the main board. I have one wire hooked to the FAST harness, the pink key switched wire. Changed this several times through my endeavor.
The main red and black wires went to the battery. Every time it burnt up the ecu the crank trigger stopped reading. The crank trigger is a 2 wire system shielded and grounded on the sensor end. I used weather packs as the plug. I later cut the weather pack off and went with spade connectors to eliminate the weather pack. Then had a friend cut those connectors off and redo the connection just to eliminate myself from the problem lol. As I type this I remember moving the crank trigger away from the altinator, then removing the altinator, after I relocated the crank trigger to the oil pump side of the motor. Also changed where the shielding wire bolted to the motor and the routing of the crank trigger wires. Pulled the working crank trigger off the Valiant and swapped them out to eliminate that.


So I started looking other places. I PM'd Monty here about a Holley system but later decided that since I have FAST sensors all ready, to get a top of the line black ECU and new harness straight from the FAST tech guy. This eliminated the 1st ECU and harness and now I have a spare. It ran good till I started running the car hard again, then it would just turn off. It didn't burn up this time but the logger looks like you unhook the battery wile making a pass. Later learned my red box was an early one and the later ecu has more filtering like Monty talks about Holley doing.


So I looked else where. Changed cap, wires, rotor, the plugs were new a few times so I have changed brands now lol. Added another Battery to fight voltage drop. Started adding grounds to everything even the stupid stuff like relays and heads and chassi etc.. it still ain't fix


So I keep reading on the Web. Post my soap opera on a few turbo sites on the Web and get a few people that want to help. Monty being one
the suggestions are stuff I have not try'd so I keep at it.


I can turn it down to 15 psi of boost and run a hi 4 in the 1\8 but that's not what I built it for. This thing will go mid 4's once I can keep it running from A to B. It's went 130mph in the 1/8 and I was peddling it like John Force looking for Elvis. It never got above 6 grand.

I know this is a little past what Gregsdart started this post for but I'm really glad he did. If it saves one guy an issue then good. But this is almost the exact thing I needed to get a handle on my car. Just the information about the plug wires for me was invaluable. To me a Taylor wire has been top of the line for years. I'll be ordering fire core wires this week lol

I will be rewiring my car front to back in the next couple weeks and will prolly wire it like a boat. Every ground going to the battery. I do have a few questions, I have two yellow tops. Should I run the grounds from things like water pump, intercooler pump, turbo oil pump, and electric fan to one battery and the electronics to the other? What about the starter and lights? Do you still ground both battery's to the chassi but still run dedicated grounds?
Monty, next time you get to Bowling Green gimme me a yell. I'm an hour north. I owe you lunch




My year was a learning year. This is my 1st turbo race car. Many guys on this site know I have been building this thing since 2007. Monty and myself bumped heads when I started, but it was because of miscommunication. .after I met him at the track, seen him and the Buick at the track etc I seen he was a welth of knowledge and would honstly try to help
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/11/15 11:22 PM

Quote:

All I know is that I run a MSD 7AL2 box. I wanted to see how much noise there was on the grounds from the box so I dug out my scope and Rogowski coil. Bet most people don't know what a Rogowski coil is - it is a flexible core current transducer. Mine has a bandwidth of 5 to 8 mhz so it is designed to measure high frequency current.

There was so much noise it was impossible to measure. I got no idea how any of the electronics works with all that noise.... This is also interesting. I was lead to believe the frequency's at the box were of the lower variety. Another think I'll ask about.
Doug

.
Posted By: Quicktree

Re: Grounding for battery in the trunck? - 01/11/15 11:37 PM

the deal is there is no down side to wire a car as Monte has described, thats the bottom line
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/11/15 11:38 PM

What you MUST remember about ANY ECU, is that it is a microprocessor and is such is sensitive to outside influences, sometimes regardless of the filtering. Plus the filtering can NOT protect the box from outside sources anyway.

Here is a rundown of how I have been wiring EFI cars for a few years and so far, I have had ZERO problems with noise.

I make a copper buss bar about 1.5" wide and 6-8" long. I drill holes varying from 1/4" to 3/8" along it's length. I then mount the buss bar under the dash on rubber isolators, like comes with an MSD box. I run a minimum of a 1 gauge wire directly from the battery to buss bar. I then run a 1 gauge wire from this same buss bar post to the motor plate and from motor plate to each head. That is all that is on THIS post on buss bar. The ECU power and ground runs directly to battery. NOT the cutoff, but TO THE BATTERY. All other items, like pumps, fans, coils, etc, ground to various lugs on buss bar. Now obviously, with a ground running to motor plate and heads, the chassis itself IS grounded, but it is NOT my primary ground circuit. And as I said earlier, the only thing I actually ground to the chassis or sheetmetal itself, is the lighting circuit. I also ALWAYS use a Ford starter relay on ANY car I wire. This and use a LARGE cable from batt to relay and from relay to starter. This gets you FULL battery power while cranking. I also do NOT stack a bunch of 12 volts feeds for other items on the relay itself. If I need other feeds, I run a 1 gauge cable from batt side of relay, to an isolated terminal stud to pick up power from. You may say that's "the same as" stacking feeds on input side of relay.......NO, it's NOT. Also use a "shielded" trigger wire on the crank and cam sensors. Given the option, ground the shield through the ECU itself, or INSIDE the car on Buss bar...NOT on the engine end. Be sure and run the cam/crank sensor wiring by itself and totally separate of ANY other wiring where possible. "In the harness" with other wiring, about guarantees you a problem.

Hope this helps

Monte
Posted By: TheOtherDodge

Re: Grounding for battery in the trunck? - 01/12/15 02:11 AM

Quote:

What you MUST remember about ANY ECU, is that it is a microprocessor and is such is sensitive to outside influences, sometimes regardless of the filtering. Plus the filtering can NOT protect the box from outside sources anyway.

Here is a rundown of how I have been wiring EFI cars for a few years and so far, I have had ZERO problems with noise.

I make a copper buss bar about 1.5" wide and 6-8" long. I drill holes varying from 1/4" to 3/8" along it's length. I then mount the buss bar under the dash on rubber isolators, like comes with an MSD box. I run a minimum of a 1 gauge wire directly from the battery to buss bar. I then run a 1 gauge wire from this same buss bar post to the motor plate and from motor plate to each head. That is all that is on THIS post on buss bar. The ECU power and ground runs directly to battery. NOT the cutoff, but TO THE BATTERY. All other items, like pumps, fans, coils, etc, ground to various lugs on buss bar. Now obviously, with a ground running to motor plate and heads, the chassis itself IS grounded, but it is NOT my primary ground circuit. And as I said earlier, the only thing I actually ground to the chassis or sheetmetal itself, is the lighting circuit. I also ALWAYS use a Ford starter relay on ANY car I wire. This and use a LARGE cable from batt to relay and from relay to starter. This gets you FULL battery power while cranking. I also do NOT stack a bunch of 12 volts feeds for other items on the relay itself. If I need other feeds, I run a 1 gauge cable from batt side of relay, to an isolated terminal stud to pick up power from. You may say that's "the same as" stacking feeds on input side of relay.......NO, it's NOT. Also use a "shielded" trigger wire on the crank and cam sensors. Given the option, ground the shield through the ECU itself, or INSIDE the car on Buss bar...NOT on the engine end. Be sure and run the cam/crank sensor wiring by itself and totally separate of ANY other wiring where possible. "In the harness" with other wiring, about guarantees you a problem.

Hope this helps

Monte




Street Car, Race Car, Street Car named Desire, this sounds like the sure-fire way of NOT running into any issues with electronics, which I believe is his point.
Posted By: Airwoofer

Re: Grounding for battery in the trunck? - 01/12/15 05:31 PM

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Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte




So Monte, are you saying that the only stuff that is critical to have the floating ground is the electronic stuff and not necessarily the rest of the analog stuff like starter, lights, fan, water pump, etc...? That's a whole lot easier to swallow than a complete rewire of a car to add EFI. Them wires under the dash are hard to get to on my junk, and the dash isn't coming out without cutting bars.




You are asking for a MAJOR headache with what you want to do...........and if I recall correctly, is the EXACT reason that I am not wiring your car for you. I told that I WOULD NOT do it, unless you let me rip all that stock crap out and wire the car RIGHT and you were NOT on board with that. You are asking for a MAJOR headache. Been there, done that and won't do it again. We have HAD this conversation standing in my shop. I refuse to chase gremlins on a car with a modern EFI and 40 year old factory wiring. Not worth it

Monte




Someone misunderstood my question. So I will ask again... Is it acceptable to have the electronic stuff like ign and modules operating on one power system and the analog stuff on another, thus maybe avoiding the noise spikes from water pump, fans, fuel pumps, lights, line lock, TB? They meet at the battery terminals.

I wasn't asking you to rewire my car in the message, and I have (unfortunately perhaps) moved away from the idea of EFI and will blow through instead.

You also had a lot on your mind that day.
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/12/15 06:11 PM

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Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.


Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.

What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights

Monte




So Monte, are you saying that the only stuff that is critical to have the floating ground is the electronic stuff and not necessarily the rest of the analog stuff like starter, lights, fan, water pump, etc...? That's a whole lot easier to swallow than a complete rewire of a car to add EFI. Them wires under the dash are hard to get to on my junk, and the dash isn't coming out without cutting bars.




You are asking for a MAJOR headache with what you want to do...........and if I recall correctly, is the EXACT reason that I am not wiring your car for you. I told that I WOULD NOT do it, unless you let me rip all that stock crap out and wire the car RIGHT and you were NOT on board with that. You are asking for a MAJOR headache. Been there, done that and won't do it again. We have HAD this conversation standing in my shop. I refuse to chase gremlins on a car with a modern EFI and 40 year old factory wiring. Not worth it

Monte




Someone misunderstood my question. So I will ask again... Is it acceptable to have the electronic stuff like ign and modules operating on one power system and the analog stuff on another, thus maybe avoiding the noise spikes from water pump, fans, fuel pumps, lights, line lock, TB? They meet at the battery terminals.

I wasn't asking you to rewire my car in the message, and I have (unfortunately perhaps) moved away from the idea of EFI and will blow through instead.

You also had a lot on your mind that day.


I know you weren't asking me to wire your car. But you asked a question and I answered it. And the answer was, in my opinion, it is a MISTAKE to try and integrate modern electronics hand in hand with 40 year old wiring. You are talking about two totally separate systems. Well how you gonna do that. You have ONE car and ONE battery, so how are you going to have stock stuff on this circuit and new stuff on this circuit. It just doesn't work that way.

So in my opinion and this is strictly MY opinion........you are making two serious mistakes. The first is going blowthrough, the second is not rewiring the car.

And it doesn't matter what I had on my mind or what was going on. My thoughts on your project haven't changed. All that factory wiring serves ZERO purpose for what you intend to do and is only asking for trouble to leave it in there..........Not to mention this has been a race car for a long time and all sorts of wiring changes over the years. So STRIP it, do it RIGHT. You didn't want to.

Monte
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/12/15 06:44 PM

Monte.. I'm still not clear on this... when using a
isolated ground... would you run all the sensor grounds
to the buss bar or to the chassis.. my way of thinking
is that all the sensors(low voltage) would go to the
isolated buss
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/12/15 06:51 PM

I thought I made it pretty clear.........I don't wire ANY grounds to the chassis, other than the lights. Also not exactly sure what "sensors" you are talking about, as they wire through a "sensor ground" output in the ECU anyway

Monte
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/12/15 06:56 PM

Quote:

I thought I made it pretty clear.........I don't wire ANY grounds to the chassis, other than the lights. Also not exactly sure what "sensors" you are talking about, as they wire through a "sensor ground" output in the ECU anyway

Monte




Ok... yeah I forgot they go through the ECU... ok..
I should be fine
Posted By: Airwoofer

Re: Grounding for battery in the trunck? - 01/12/15 07:10 PM

Quote:



So in my opinion and this is strictly MY opinion........you are making two serious mistakes. The first is going blowthrough, the second is not rewiring the car.

And it doesn't matter what I had on my mind or what was going on. My thoughts on your project haven't changed. All that factory wiring serves ZERO purpose for what you intend to do and is only asking for trouble to leave it in there..........Not to mention this has been a race car for a long time and all sorts of wiring changes over the years. So STRIP it, do it RIGHT. You didn't want to.

Monte




I went through a complete re-wire on my plane and it was a real pain. I did just about what you described but it isn't laden with a bunch of electronic stuff. Mike rewired the race stuff on the car just before I bought it from him and I intend to replace almost all of that stuff he did to suit my preferences, and gain room for a passenger to sit in the right seat by relocating the MSD 3. Problem is with the left-right bar blocking the dash it all has to be done while laying on your back on the floor looking up into the underdash. Maybe it is my belief that I wouldn't ask anybody to something I wouldn't. Working on my back is just plain painful to me with the plate in my neck. Luckily the car wiring itself is pretty much unmolested (ie the lights work), so all I need to do is change the race car stuff, relocate the MSD box and the switches. The dash isn't coming out anytime soon. Too bad cause I would change it to a rally.

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/12/15 07:26 PM

Quote:

Quote:



So in my opinion and this is strictly MY opinion........you are making two serious mistakes. The first is going blowthrough, the second is not rewiring the car.

And it doesn't matter what I had on my mind or what was going on. My thoughts on your project haven't changed. All that factory wiring serves ZERO purpose for what you intend to do and is only asking for trouble to leave it in there..........Not to mention this has been a race car for a long time and all sorts of wiring changes over the years. So STRIP it, do it RIGHT. You didn't want to.

Monte




I went through a complete re-wire on my plane and it was a real pain. I did just about what you described but it isn't laden with a bunch of electronic stuff. Mike rewired the race stuff on the car just before I bought it from him and I intend to replace almost all of that stuff he did to suit my preferences, and gain room for a passenger to sit in the right seat by relocating the MSD 3. Problem is with the left-right bar blocking the dash it all has to be done while laying on your back on the floor looking up into the underdash. Maybe it is my belief that I wouldn't ask anybody to something I wouldn't. Working on my back is just plain painful to me with the plate in my neck. Luckily the car wiring itself is pretty much unmolested (ie the lights work), so all I need to do is change the race car stuff, relocate the MSD box and the switches. The dash isn't coming out anytime soon. Too bad cause I would change it to a rally.

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.


I never said it would be easy........I just said what SHOULD be done. I have laid on my back in a MANY a car and rewired the whole thing. You just have to do what you have to do. You build the harness OUTSIDE the car anyway and then install it. The "lights work" is also not a very sound way to determine the validity of a wiring harness either.

Obviously you are going to do it the way YOU want to do it and are just trying to get somebody to tell you that it will be fine. Maybe it will, maybe it won't........who knows. My point was that MYSELF, I wouldn't risk it. And from my side........if I wired the car the way YOU wanted it and then there were issues, those "issues" fall on ME to find and fix. Sorry, but given those options, I will pass on the job instead of just taking the money to do something I feel is wrong and may potentially cause me and you both real grief.

Monte
Posted By: Airwoofer

Re: Grounding for battery in the trunck? - 01/12/15 11:45 PM

Quote:

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.




Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.

Attached picture 8393930-racestuff.jpg
Posted By: gregsdart

Re: Grounding for battery in the trunck? - 01/13/15 12:15 AM

To all that are following this thread, as the OP I would like to invite any other electrical knowledge anyone is willing to post here, in the hopes this thread will become a great resource(it already has WAY surpassed my expectations!!!) for all of us, especially now in the age where we are getting into more and more sensitive electrical issues and systems.
One thing that comes to mind would be charts like used to figure wire gauge for load and length, etc. Math used in electrical work is another.
At this time I would also like to thank all that posted here with info. I appreciate it, and have learned a lot so far. Thanks, Greg
Posted By: slammedR/T

Re: Grounding for battery in the trunck? - 01/13/15 01:00 AM

Monte;
I for one appreciate all the info you have given, I have printed it out and will be re-wiring my truck as I'm guilty of using the rollcage/chassis as my main ground point. I also switched to firecore50 plug wires from my moroso ultra40's (they were old anyway). I also appreciate you answering my questions I asked you and hope to see you at a track soon
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/13/15 01:29 AM

Quote:

Quote:

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.




Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.


It looks like someone tried to do a tidy job here. But I see something I don't like. Why have 6 relays that are nowhere near the device they are controlling? Also why control the relay with the same size wire that feeds the device? I would suggest placeing the relay near the device, water pump, fuel pump, fan, etc. Feed the relay with sufficient gauge to run the device ( 12ga, might even need larger) direct from the nearest power source. I like to use the battery cutoff positive feed terminal for the fuel pump. The alternator output or firewall pass through for the fans, etc. The control circuit can be light duty. My relay power feeds run a fusible link. They could be fused but my feeling is if the water pump, fuel pump shorts bad enough to kill the fusible link that item is toast anyway. In the pic the relays are on the motor plate for the water pump and 2 fans. The alternator on one side, coil and crank trigger on the other. Coil and crank trigger wire run down the right side. The alternator on the left
Doug

Attached picture 8394041-E18.jpg
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 01/13/15 02:12 AM

Quote:

Quote:

I thought I made it pretty clear.........I don't wire ANY grounds to the chassis, other than the lights. Also not exactly sure what "sensors" you are talking about, as they wire through a "sensor ground" output in the ECU anyway

Monte




Ok... yeah I forgot they go through the ECU... ok..
I should be fine



That is why the ECU + and - go direct to the battery, so they are as isolated as possible from EVERYTHING, including the isolated ground. Im guessing that grounding the chassis solely amplifys EMI for everything. I think I get it.
Posted By: David_in_St_Croi

Re: Grounding for battery in the trunck? - 01/13/15 02:44 AM

Quote:

To all that are following this thread, as the OP I would like to invite any other electrical knowledge anyone is willing to post here, in the hopes this thread will become a great resource(it already has WAY surpassed my expectations!!!) for all of us, especially now in the age where we are getting into more and more sensitive electrical issues and systems.
One thing that comes to mind would be charts like used to figure wire gauge for load and length, etc. Math used in electrical work is another.
At this time I would also like to thank all that posted here with info. I appreciate it, and have learned a lot so far. Thanks, Greg




Here is the basic formula for wire sizing. I use it when designing boat electrical systems. With a composite boat, you are grounding back to the battery, similar to how Monte describes. The formula is as follows: CM = K*L*I/E

This will give you the wire required in what is called circular mils. There are conversions from circular mils to AWG on the internet

Now, here is the definition of the variables mentioned.
K is a constant representing the resistance of copper, it is 10.75 ohms /mil-foot
I = load current in amperes
L = length of conductor from centre of distribution, in feet
E = voltage drop at load, in volts

If it is a system where you have the ground going back to the battery, multiply by two.

Now, the rest is relatively straight forward. Load is given by the manufacturer of the device.

Length of conductor, get a tape measure and read it correctly.

Voltage drop: sort of like how fast do you want to go, how much do you have to spend? For a boat inspected by the USCG, you can have a voltage drop as high as 10%. The other standard in the marine world is 3% voltage drop. You want less voltage drop, there are three things you can do. One is to shorten the length of the run. This has the advantage of using less wire, which is less cost and weight. Second is to up voltage. Third is to go to a larger wire size.

I have a spreadsheet written to do this, it was not hard to create.

I use tinned marine grade wire wherever possible, and the end connectors from Pacer or Ancor that have the adhesive heat shrink insulation.

Hope I have not muddied the waters too much.

Regards, Dave
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/13/15 03:07 AM

Quote:

Quote:

Quote:

I thought I made it pretty clear.........I don't wire ANY grounds to the chassis, other than the lights. Also not exactly sure what "sensors" you are talking about, as they wire through a "sensor ground" output in the ECU anyway

Monte




Ok... yeah I forgot they go through the ECU... ok..
I should be fine



That is why the ECU + and - go direct to the battery, so they are as isolated as possible from EVERYTHING, including the isolated ground. Im guessing that grounding the chassis solely amplifys EMI for everything. I think I get it.




I thought it was to maintain the memory... but I did
run direct to the battery
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 01/13/15 03:42 AM

Quote:

Quote:

To all that are following this thread, as the OP I would like to invite any other electrical knowledge anyone is willing to post here, in the hopes this thread will become a great resource(it already has WAY surpassed my expectations!!!) for all of us, especially now in the age where we are getting into more and more sensitive electrical issues and systems.
One thing that comes to mind would be charts like used to figure wire gauge for load and length, etc. Math used in electrical work is another.
At this time I would also like to thank all that posted here with info. I appreciate it, and have learned a lot so far. Thanks, Greg




Here is the basic formula for wire sizing. I use it when designing boat electrical systems. With a composite boat, you are grounding back to the battery, similar to how Monte describes. The formula is as follows: CM = K*L*I/E

This will give you the wire required in what is called circular mils. There are conversions from circular mils to AWG on the internet

Now, here is the definition of the variables mentioned.
K is a constant representing the resistance of copper, it is 10.75 ohms /mil-foot
I = load current in amperes
L = length of conductor from centre of distribution, in feet
E = voltage drop at load, in volts

If it is a system where you have the ground going back to the battery, multiply by two.

Now, the rest is relatively straight forward. Load is given by the manufacturer of the device.

Length of conductor, get a tape measure and read it correctly.

Voltage drop: sort of like how fast do you want to go, how much do you have to spend? For a boat inspected by the USCG, you can have a voltage drop as high as 10%. The other standard in the marine world is 3% voltage drop. You want less voltage drop, there are three things you can do. One is to shorten the length of the run. This has the advantage of using less wire, which is less cost and weight. Second is to up voltage. Third is to go to a larger wire size.

I have a spreadsheet written to do this, it was not hard to create.

I use tinned marine grade wire wherever possible, and the end connectors from Pacer or Ancor that have the adhesive heat shrink insulation.

Hope I have not muddied the waters too much.

Regards, Dave


Would you consider the tinned marine grade cable a better conductor than say the solid copper SGX? I understand the tinning is for corrosion prevention?
Posted By: David_in_St_Croi

Re: Grounding for battery in the trunck? - 01/13/15 03:50 AM

In our environment I am primarily using the tinned marine grade for corrosion protection. Plus it is readily available from the boat builder I used to work for as a naval architect. It does seem to solder a bit better if you are making any connections that way. We are ground zero for corrosion so more of a consideration for us than most.
Posted By: Adobedude

Re: Grounding for battery in the trunck? - 01/13/15 05:59 AM

I agree with Monte, keep the relays close to the what it's triggering, with that said, I use the Relays on my ARC switch panel to trigger another a relay close to what it's running

FP in the back pulling power off the battery, fan, water pump in the front. I really like using Leash Electronics small relay boards, they are fused and easy to wire in.

All my signal wires are either twisted pair or Shielded Tefzel wire

All my grounds go to a couple isolated lugs that are grounded back to the battery.

When sizing what ga wire to use, include the length of the ground.

Panel before it was finished.

Posted By: bonefish

Re: Grounding for battery in the trunck? - 01/13/15 03:23 PM

After seeing the way you guys do things I realize its a MIRACLE any of my stuff works at all.
Posted By: Airwoofer

Re: Grounding for battery in the trunck? - 01/13/15 05:36 PM

This is a great thread.

There is a plastic plate in my Demon similar to the one I posted a pic of which looks to be aluminum (and bolted to the cage). My MSD7-3 sticks out in the passenger area just like that example which is kind of a pain for passengers. Also has an electrical do-dad to time the Naws second system, and some other stuff on it. The fuse block is under the dash, switches for all the race stuff on the shifter. None is as pretty as the pic I posted which is from a guy here's website.

This is now a street car that I play at the track with, driving there if I feel like it. I will be replacing all the race wiring Mike put in cause I want my switches located up front and the line loc / TB behind the shifter on their own stand. So, as I plan to rewire the car and all this talk of isolating grounds comes up, I chimed in. Here is why:

I also am taking the naws off the 496 and am gonna first run it NA on (10-1) pump swill. I wanted to boost the motor instead of spray to get the same 1200 HP, and to keep things under the cowl a 90* setup off the tall single plane (that matches the heads), with a EFI throttle body would have been way better than a blow through. Blowing through a Dom on a tall manifold will make me have to cut a hole in the hood for the hat.

After I got the news about wiring from Monte and having to completely rip out the 44 yr old stuff, my plans changed immediately. Especially after an hour later where I was offered a killer deal on a E-85 blow through V7-YSi setup that I could watch run that night on the car. Way, way cheaper and not sensitive to stray electrons any more than the NA setup. So I jumped on the deal.

But the car still needs the race stuff redone and I would like to do that right. I would still like to know why running the car stuff as is (I include the water pump, fuel pumps, fans, line loc, TB in that category also) and the race stuff (electronic ign) on a separate circuit won't work. Hell, the thing went mid 9000's like this so the sparks were sparking.

Another thing is the new wires will be user friendly and easy to get to. It is a real pain to try to crawl backwards over X door bars to get to a fuse or change a wire. I don't know how Mike did it.

Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/14/15 12:00 AM

Firecores are in the mail
Posted By: Polarapete

Re: Grounding for battery in the trunck? - 01/14/15 12:50 AM



This is why I love this site. I learn something new from every posting and for the most part it is very helpful in my projects.

Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/14/15 04:52 AM

Quote:

Quote:

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.




Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.


This is NOT grounded to chassis. Plate is mounted on rubber isolators

Monte
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/14/15 04:38 PM

Quote:

To all that are following this thread, as the OP I would like to invite any other electrical knowledge anyone is willing to post here, in the hopes this thread will become a great resource(it already has WAY surpassed my expectations!!!) for all of us, especially now in the age where we are getting into more and more sensitive electrical issues and systems.
One thing that comes to mind would be charts like used to figure wire gauge for load and length, etc. Math used in electrical work is another.
At this time I would also like to thank all that posted here with info. I appreciate it, and have learned a lot so far. Thanks, Greg


Radiator electrolysis can be a real killer of aluminum radiators. To test, VOM on 2 vlt scale. Negative probe to a known good grd. Positive probe in the coolant ( make sure it does not touch rad neck, etc). Take a reading. Take another reading while starter is engaged. Start the car and turn all electrical circuits on. A reading of .2 volts or above = bad ground. A change in voltage as you turn circuits on and off is a good way to isolate the problem. This is referred to as type "A" electrolysis. If the voltage does not vary as you turn stuff on and off, but remains above .2 vlts, that is referred to as type "B" electrolysis. This indicates acidic fluid. Dump the coolant, flush the system, and replace the coolant. OR, a quick check = stick your finger in the coolant. If it comes out black, you have an electrolysis problem. Obviously bad news for heads, block, or anything else aluminum. A "known good ground" would be the - battery post.
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/17/15 11:08 PM

As I said when more information was available I would post it. Some understand the next paragraph. So for those who don't. When current is flowing through a wire there are magnetic lines of force that encircle the wire. The closer another wire is to the current carrying conductor the more the likely hood that those magnetic lines of force will induce current in the 2nd wire. We also can have voltage "leakage" where the insulator isn't sufficient and voltage can jump to the next wire. The last item that has been talked about is "flyback". An example of flyback would be when the circuit for the primary winding in the coil is opened its magnetic field collapses. This induces voltage in the secondary winding firing the plug. When this energy dissipates through the secondary winding it induces voltage back into the primary winding. This voltage is known as flyback. After talking to 6 electrical engineers I was directed by all of them to go and talk to the same person. This is what I learned from our EE PHD. As we've talked about having all the grounds in close proximity is a good idea. He was right on board with Monty's copper bar. He also liked the separate ground cable, but for a different reason. Running both a separate ground cable and the positive lead side by side helps cancel noise. That could be the same reason running the box leads to the battery was beneficial (leads side by side). His definition of what he thought would be the very best wiring.
#1 both hot and ground cables side by side.
#2 the hot cable directly to the starter, with feeds to a remote power stud and the alternator.
#3 the ground to the copper ground block.
#4 the block and heads grounded there.
#5 clean properly sized terminals and cable.
#6 twisted pair to sensors. with optional shielding grounded at one end
#7 care in running any sensor wiring near plug wires and or power cables.
Also note: shielding helps with voltage noise but doesn't do much for magnetic force.
In closing obviously in the majority of cases we get away with less. Make the choice of what you think you need for your application. I would think after reading this thread you can make an informed decision.
Doug
Posted By: Monte_Smith

Re: Grounding for battery in the trunck? - 01/18/15 12:06 AM

Quote:

As I said when more information was available I would post it. Some understand the next paragraph. So for those who don't. When current is flowing through a wire there are magnetic lines of force that encircle the wire. The closer another wire is to the current carrying conductor the more the likely hood that those magnetic lines of force will induce current in the 2nd wire. We also can have voltage "leakage" where the insulator isn't sufficient and voltage can jump to the next wire. The last item that has been talked about is "flyback". An example of flyback would be when the circuit for the primary winding in the coil is opened its magnetic field collapses. This induces voltage in the secondary winding firing the plug. When this energy dissipates through the secondary winding it induces voltage back into the primary winding. This voltage is known as flyback. After talking to 6 electrical engineers I was directed by all of them to go and talk to the same person. This is what I learned from our EE PHD. As we've talked about having all the grounds in close proximity is a good idea. He was right on board with Monty's copper bar. He also liked the separate ground cable, but for a different reason. Running both a separate ground cable and the positive lead side by side helps cancel noise. That could be the same reason running the box leads to the battery was beneficial (leads side by side). His definition of what he thought would be the very best wiring.
#1 both hot and ground cables side by side.
#2 the hot cable directly to the starter, with feeds to a remote power stud and the alternator.
#3 the ground to the copper ground block.
#4 the block and heads grounded there.
#5 clean properly sized terminals and cable.
#6 twisted pair to sensors. with optional shielding grounded at one end
#7 care in running any sensor wiring near plug wires and or power cables.
Also note: shielding helps with voltage noise but doesn't do much for magnetic force.
In closing obviously in the majority of cases we get away with less. Make the choice of what you think you need for your application. I would think after reading this thread you can make an informed decision.
Doug


Sounds like your engineer would wire something the same as I do, with the exception that I prefer to run a Ford starter relay, in lieu of running hot wire directly to starter. Good info, glad to know I appear to be doing something right.......LOL!!

And I agree that "twisted pairs" are a good idea and I do it often with things that can backfeed, like trans brake solenoids, buttons, coil wires, hots and grounds of any electronics, etc. Guys often ask me, "how do you do that".........it's pretty simple really. The pair you want "twisted", simply put the ends of the wire in your cordless drill, tighten the chuck and twist away. Be careful, because you CAN break it if you twist them too tight.

And I know it is EASIER to say ground your trans brake or electric shift solenoid, right AT the trans or shifter.....BUT, these two items are notoriously bad for feedback when the circuit collapses. Also remember that these inputs likely run through delay boxes, shift modules, or ign boxes. Feedback can create havoc with all these devices, making consistent release and operation sketchy. So take the time, run a full length twisted pair, ground them clean and you may solve some issues.

Monte
Posted By: markz528

Re: Grounding for battery in the trunck? - 01/18/15 01:02 AM

Speaking of best practices for wiring, how many of you use free wheeling diodes on solenoids and large relays? It is a very good idea.
Posted By: jcc

Re: Grounding for battery in the trunck? - 01/18/15 04:36 AM

www.delcity.net/store/Relays-with-Diode/p_73578
Posted By: slammedR/T

Re: Grounding for battery in the trunck? - 01/18/15 07:29 AM

Quote:

Quote:

As I said when more information was available I would post it. Some understand the next paragraph. So for those who don't. When current is flowing through a wire there are magnetic lines of force that encircle the wire. The closer another wire is to the current carrying conductor the more the likely hood that those magnetic lines of force will induce current in the 2nd wire. We also can have voltage "leakage" where the insulator isn't sufficient and voltage can jump to the next wire. The last item that has been talked about is "flyback". An example of flyback would be when the circuit for the primary winding in the coil is opened its magnetic field collapses. This induces voltage in the secondary winding firing the plug. When this energy dissipates through the secondary winding it induces voltage back into the primary winding. This voltage is known as flyback. After talking to 6 electrical engineers I was directed by all of them to go and talk to the same person. This is what I learned from our EE PHD. As we've talked about having all the grounds in close proximity is a good idea. He was right on board with Monty's copper bar. He also liked the separate ground cable, but for a different reason. Running both a separate ground cable and the positive lead side by side helps cancel noise. That could be the same reason running the box leads to the battery was beneficial (leads side by side). His definition of what he thought would be the very best wiring.
#1 both hot and ground cables side by side.
#2 the hot cable directly to the starter, with feeds to a remote power stud and the alternator.
#3 the ground to the copper ground block.
#4 the block and heads grounded there.
#5 clean properly sized terminals and cable.
#6 twisted pair to sensors. with optional shielding grounded at one end
#7 care in running any sensor wiring near plug wires and or power cables.
Also note: shielding helps with voltage noise but doesn't do much for magnetic force.
In closing obviously in the majority of cases we get away with less. Make the choice of what you think you need for your application. I would think after reading this thread you can make an informed decision.
Doug


Sounds like your engineer would wire something the same as I do, with the exception that I prefer to run a Ford starter relay, in lieu of running hot wire directly to starter. Good info, glad to know I appear to be doing something right.......LOL!!

And I agree that "twisted pairs" are a good idea and I do it often with things that can backfeed, like trans brake solenoids, buttons, coil wires, hots and grounds of any electronics, etc. Guys often ask me, "how do you do that".........it's pretty simple really. The pair you want "twisted", simply put the ends of the wire in your cordless drill, tighten the chuck and twist away. Be careful, because you CAN break it if you twist them too tight.

And I know it is EASIER to say ground your trans brake or electric shift solenoid, right AT the trans or shifter.....BUT, these two items are notoriously bad for feedback when the circuit collapses. Also remember that these inputs likely run through delay boxes, shift modules, or ign boxes. Feedback can create havoc with all these devices, making consistent release and operation sketchy. So take the time, run a full length twisted pair, ground them clean and you may solve some issues.

Monte




I fixed a buddy's trans brake issue by moving the ground he had on the oil pan bolt, to a good clean ground stud inside the car. No more problems with the trans brake not working sometimes.
Posted By: Kiddart

Re: Grounding for battery in the trunck? - 01/18/15 08:40 PM

Is it bad practice to have a few different items on your car ground to the same location, for example, lights fan and ignition on the same lug.

Good or bad.

I am tracking an issue that's why I ask
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/18/15 08:46 PM

Quote:

Is it bad practice to have a few different items on your car ground to the same location, for example, lights fan and ignition on the same lug.

Good or bad.

I am tracking an issue that's why I ask



The less the better. That being said I've seen as many as three on factory locations. I run no more than 2. What issue do you have?
Doug
Posted By: Clanton

Re: Grounding for battery in the trunck? - 01/18/15 09:29 PM

Quote:

Quote:

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.




Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.



I have all that between the seat but I think that could go under the glove box with a hing to swing down access.
Posted By: 383man

Re: Grounding for battery in the trunck? - 01/18/15 09:46 PM

Mopar has used twisted wires on the 2 wire buss circuits as long as I remember working with them. They also had a single wire buss which of course you cant twist but some of the buss circuits work on about 2.5 volts at times and since its a comunication circuit between computers in the car it makes sense to do what they can to eliminate any problems. I had problems on one year of Caravans that used the older CCD buss when the eng electric fan wires ran to close to the buss wires and sometimes the van would cut out when the fan kicked on. That was a tricky one to figure out as I remember working with a Chrysler engineer on that Caravan. Ron
Posted By: Kiddart

Re: Grounding for battery in the trunck? - 01/18/15 10:35 PM

Hi Doug,
I am chasing an ignition issue. I rewired the entire car this last summer. I chose to use a 20 circuit universal harness, way more circuits than I will ever need but I did it for a reason. Since the rewire I will be driving down the street and for no reason the car just stops(Lights Out no power) it has done this just sitting in the garage running. I will cycle the power switch the care restarts and everything is fine until it happens again. its really odd but I can only think its a ground or excess of grounds together or it is in my msd box.

what are your thoughts
Posted By: MR_P_BODY

Re: Grounding for battery in the trunck? - 01/18/15 10:50 PM

Quote:

Hi Doug,
I am chasing an ignition issue. I rewired the entire car this last summer. I chose to use a 20 circuit universal harness, way more circuits than I will ever need but I did it for a reason. Since the rewire I will be driving down the street and for no reason the car just stops(Lights Out no power) it has done this just sitting in the garage running. I will cycle the power switch the care restarts and everything is fine until it happens again. its really odd but I can only think its a ground or excess of grounds together or it is in my msd box.

what are your thoughts




I would check the master shut off... to lose total
power your doing 2 things.. you killed the alt and
the battery.. the master controls both of them..
next time it does it put your multi meter across
the master and see if its open
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/19/15 03:22 AM

Quote:

Hi Doug,
I am chasing an ignition issue. I rewired the entire car this last summer. I chose to use a 20 circuit universal harness, way more circuits than I will ever need but I did it for a reason. Since the rewire I will be driving down the street and for no reason the car just stops(Lights Out no power) it has done this just sitting in the garage running. I will cycle the power switch the care restarts and everything is fine until it happens again. its really odd but I can only think its a ground or excess of grounds together or it is in my msd box.

what are your thoughts



When you say lights out do you mean more than just the engine?
Doug
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 01/19/15 06:22 AM

I think I will run an extra ground cable to the front going under fender to ground headlights,fans and horn to. Then have that connect to bussbar under dash too.
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 01/19/15 06:24 AM

Quote:

Quote:

Hi Doug,
I am chasing an ignition issue. I rewired the entire car this last summer. I chose to use a 20 circuit universal harness, way more circuits than I will ever need but I did it for a reason. Since the rewire I will be driving down the street and for no reason the car just stops(Lights Out no power) it has done this just sitting in the garage running. I will cycle the power switch the care restarts and everything is fine until it happens again. its really odd but I can only think its a ground or excess of grounds together or it is in my msd box.

what are your thoughts



When you say lights out do you mean more than just the engine?
Doug


Do you still have the factory bulkheads at the firewall?
Posted By: Kiddart

Re: Grounding for battery in the trunck? - 01/19/15 05:26 PM

yes Lights out means all power the car sputters to a stop all lights, fans, fuel pump etc. go out. I probly should replace my Shut off switch. I am also going to separate all my grounds as was mentioned above. Lights with Light, Fuel by its self, fan by its self and ignition by itself. I have all winter to figure this out. but already cant wait to drive it ion the spring
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/19/15 09:47 PM

You have what is commonlly called a Hi Joint, high restance open, in the low power electrical industry(communications). It is proablly cause by the bad joint heating up, when it gets hot enough it opens up and quits conducting, very hard to find when it works, easy to find when it doesn't work(open circuit) with a Volt Ohm meter, even using a test light can find them when they are not conducting Let us know what you find, BTW I had a Moroso battery cut off switch slowly go bad causing me to melt two of the battery terminals in my old Duster, what a mess Lots of gremlins out there Let us know what you find and do to correct it
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/22/15 09:38 PM

Quote:

yes Lights out means all power the car sputters to a stop all lights, fans, fuel pump etc. go out. I probly should replace my Shut off switch. I am also going to separate all my grounds as was mentioned above. Lights with Light, Fuel by its self, fan by its self and ignition by itself. I have all winter to figure this out. but already cant wait to drive it ion the spring



I would agree bad main ground connection, power feed connection, or Faulty cutoff switch. A voltage drop test will find it. Connect the voltmeter from the negative battery terminal to the next connection in line (negative to negative). The meter should read very little.2 volts or so. Do the same thing on the positive side (positive battery terminal to the next positive connection inline). If you see a high voltage reading you've found your issue.
Doug
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 01/22/15 10:04 PM

Quote:

yes Lights out means all power the car sputters to a stop all lights, fans, fuel pump etc. go out. I probly should replace my Shut off switch. I am also going to separate all my grounds as was mentioned above. Lights with Light, Fuel by its self, fan by its self and ignition by itself. I have all winter to figure this out. but already cant wait to drive it ion the spring



Top left couple wires at the firewall side of bulkhead is a fuseable link wire. I would bet that is your problem.

On a side note I ordered a piece of 1/4" copper flat stock for my heap.
Posted By: HemiDart68

Re: Grounding for battery in the trunck? - 01/22/15 10:50 PM

I have wired a few cars grounding everything to the frame. Yes, everything on the car worked. My newest car I wired it with floating grounds/busbar in the car. Then used ground cables to both heads. I used an alternator and ran a seperate battery cable to the alternator from the battery. Basically went wild with battery cable. Now thta its done I'm a believer. I think this car seems to crank better, charge better, start easier than any i have had in the past. Maybe its my imagination, but I really think it works I'm drinking the kool-aid on no chassis grounds. I know it adds work to ground this way instead of chassis but i think its worth it. I have done wiring work on offshore performance boats and you have to wire this way (no chassis).
Posted By: Airwoofer

Re: Grounding for battery in the trunck? - 01/22/15 11:23 PM

Quote:

Quote:

Quote:

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.




Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.



I have all that between the seat but I think that could go under the glove box with a hinge to swing down access.




That is exactly what I was thinking of doing!
Posted By: dvw

Re: Grounding for battery in the trunck? - 01/22/15 11:32 PM

Quote:

Quote:

Quote:

Quote:

So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.




Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.



I have all that between the seat but I think that could go under the glove box with a hinge to swing down access.




That is exactly what I was thinking of doing!



How about behind the glove box, door swings down
Doug.

Attached picture 8404869-E18.jpg
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 01/23/15 01:23 AM

I stuck my new plug wires on the ohm meter. Going through the cap and wire I can see a big difference between the Taylor's and Fire cores.
I went with the HEI style cap lugs, (male) over the mopar style (female)
The Taylor's were 1.4 ohms

Fire cores were .13 ohms.
Posted By: Cab_Burge

Re: Grounding for battery in the trunck? - 01/23/15 06:15 AM

Quote:

I stuck my new plug wires on the ohm meter. Going through the cap and wire I can see a big difference between the Taylor's and Fire cores.
I went with the HEI style cap lugs, (male) over the mopar style (female)
The Taylor's were 1.4 ohms

Fire cores were .13 ohms.


One thing you need to remember on how the spark travels down the spark plug wires and how your testing the conductor that carrys the spark, electricity, (the ohm meter uses it low voltage internal battery to conduct the ohm test with minimal voltage) will always take the easiest path that will carry the load. The ohm test is testing the easeist path with very low voltage and almost no amps You should probally take the connectors off of each end of the spark plug wires and test the inner graphite nylon core that the ignition spark will travel down to the the spark plug, not the tiny outer stainless wires that the spark won't travel due to it having a lot higher restitance than the inner core, when new, do to the overall length. Spark plug wires wear out with use, the higher the resitance to the spark the faster they wear out I've seen the inner graphite coating burnt off of the nylon centers on the early radio suppression spark plug wires that didn't have the outer stainless wire wrapped around them like a lot of the new Hi Po wires for racing have now I had a miss that had affected the three shorter wires,#4,6 and 8, on the passenger side of my old 440 powered bracket Duster. It would start to miss the last three hundred feet of the 1/4 mile,those plugs look a litle different, not fouled, but not as clean as the rest of the plugs. I ohmed the wires and found those three wires where not testing like the rest of the wires and took them apart to find out why Be careful when it comes to racing and trouble shooting, it can drive you absolutely nuts
Posted By: Crizila

Re: Grounding for battery in the trunck? - 01/24/15 02:25 AM

Quote:

I stuck my new plug wires on the ohm meter. Going through the cap and wire I can see a big difference between the Taylor's and Fire cores.
I went with the HEI style cap lugs, (male) over the mopar style (female)
The Taylor's were 1.4 ohms

Fire cores were .13 ohms.


Comparing apples and oranges. Doesn't have anything to do with which wire is best. You can use an ohm test with wires of the same Mfg. Obviously the longer wires will test a little higher than the shorter ones, but what you are looking for is one wire that is way out of wack. What hurts wires is heat, improper removal, Lots of on and off the plugs ( especially when they are still hot ). I only used heat jacketed wires. I use lots of dielectric grease inside the plug boots, use a boot puller when I can, give the boots a little twist to break them loose from the plug before I tug on them, never pull on the wire to remove them and try not to remove/install them hot when I can. I like HEI style caps, keep the wires separated as much as possible, and don't run any other wiring near them. I do use the chasis for a ground on my non-electronic race car.

Attached picture 8405915-blowermocup1.jpg
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 02/04/15 04:04 AM

Applied some of my Moparts/Monte Smith learned knowledge on my engines ground strategy today. Also went ahead and routed my charge wire from the alternator in 4/0 AWG. I feel more confident the chances of a bunch of electrical gremlins wont get me this go around.
Posted By: slammedR/T

Re: Grounding for battery in the trunck? - 02/04/15 04:27 AM

Quote:

Applied some of my Moparts/Monte Smith learned knowledge on my engines ground strategy today. Also went ahead and routed my charge wire from the alternator in 4/0 AWG. I feel more confident the chances of a bunch of electrical gremlins wont get me this go around.





Posted By: FastmOp

Re: Grounding for battery in the trunck? - 02/05/15 02:28 AM

Today I made this for my grounds to run too. Since I ran most of the grounds back to the Battery, I'm going to run this in the trunk and tie it to the battery with a welding lead.and ground everything here.

Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 02/05/15 03:20 AM

Quote:

Today I made this for my grounds to run too. Since I ran most of the grounds back to the Battery, I'm going to run this in the trunk and tie it to the battery with a welding lead.and ground everything here.




I purchased a piece of 1/4" copper plate to Richard, ridiculous how heavy it is. What screws are you using on yours?
Posted By: FastmOp

Re: Grounding for battery in the trunck? - 02/05/15 03:40 AM

5 inches long X 2 inches wide X .375 thick.Its about 3 pounds lol.

I went with some brass screws I had, small are 6-32. I'd go larger next time.
Large screws are 10-24. The small ones are no fun to tap.use a lot of WD40.
I'll have my isolators in the morning and the Copper lugs for the big screws and should get farther along soon. This is one of my last projects. It's almost ready to try again.

Our tracks open in 24 days
Posted By: 72Swinger

Re: Grounding for battery in the trunck? - 02/05/15 05:06 AM

Cool Richard, keep us informed with whatever changes occur with the new HD ground setup and how the car runs, good or bad.
Posted By: cudaman1969

Re: Grounding for battery in the trunck? - 03/03/15 02:58 AM

Ok I'm going to ask the most ridiculous questions on here, what is "noise" - "shielding" ? There's more but I'll start here.
Posted By: 68cuda440

Re: Grounding for battery in the trunck? - 03/03/15 05:36 AM

Quote:

Ok I'm going to ask the most ridiculous questions on here, what is "noise" - "shielding" ? There's more but I'll start here.




Noise can be any unwanted electrical signals. Solid grounds help reduce noise. One source of high frequency noise in your engine compartment are the spark plug wires, especially if they are solid core or non-suppression type.

EMI/RFI - http://electronicdesign.com/energy/understanding-emi-noise-power-system-design

Shielding is a cover or other device to absorb / redirect noise away from your signal. One way to shield signal wires is to use a braided wire covering, AKA shield wire, that is grounded on one end and acts as a antenna to gather these signals and take them to ground.
Posted By: radar

Re: Grounding for battery in the trunck? - 03/03/15 06:10 AM

I read this whole thread and found the best solution- solid gold everything!

Trust me it'll be worth the weight penalty!
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