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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.

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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

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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.

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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

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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.

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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

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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!

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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

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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

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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

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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

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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

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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

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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

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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.

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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.

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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

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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.

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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

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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.

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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

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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.

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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

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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.

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