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60 ft frustration is driving me nuts

Posted By: dvw

60 ft frustration is driving me nuts - 06/15/20 05:08 PM

Though we won last weekend the car hasn't been good. 60ft varies wildly. 3 different tracks. This weekend rd 1 1.40, rd 2 1.29. Its been as wide a spread as 1.29-1.46. Car leaves flat, deviously 12-16" up for 40-60foot out. What I've done to try and fix it. New M/T 10.5wx31, loosened the shocks and tightened the shocks, the fronts as many as 15 clicks. Varied tires 12-15 psi. Then with video realized there is zero tire spin . Next swapped converters, new plugs, cap, rotor, carbs apart cleaned and adjusted. Varied timing by 6 degrees. Same leave rpm, water, oil temp, intake temp. Incrementals after 60ft are spot on. Same fuel I've always run, Renegade Pro114. R/T are getting slow also. However on the practice tree they're fine. Foot brake only. Leave at 2700-3300. Eddy 750 carbs. The combo has been untouched and pretty decent for 7 years. Thoughts?
Doug
Posted By: JERICOGTX

Re: 60 ft frustration is driving me nuts - 06/15/20 05:24 PM

If the 330', 660' and 1000' are the exact same, I wouldn't worry about it. Could be where your car is tripping the 60' timers.
Posted By: Al_Alguire

Re: 60 ft frustration is driving me nuts - 06/15/20 05:28 PM

Well I would be looking hard to the converter. Reaction times obvious would change with tire slippage, but if it is dead hooking and running slow on the tree and 60' I would be looking for a converter to toss in it for sure. Might look at the trans as well but sure sounds like a converter issue to me. Just went through this on a biddies S/ST car. Pulled converter and found some fins had been knocked loose from brazing, same deal. Reaction times and 60's inconsistent down track was fine.
Posted By: n20mstr

Re: 60 ft frustration is driving me nuts - 06/15/20 05:29 PM

Originally Posted by JERICOGTX
If the 330', 660' and 1000' are the exact same, I wouldn't worry about it. Could be where your car is tripping the 60' timers.


ARE your result different at different tracks? Maybe they have 60" light at different heights ? ALso do you have a transmission blanket? possible sometimes its hanging down??

Also the diff reaction times same thing, maybe the rollout is different form one track to another
Posted By: topside

Re: 60 ft frustration is driving me nuts - 06/15/20 05:37 PM

If I understand you correctly, sounds like it won't pitch-rotate and dead-hooks ?
Sounds like you've thrown some tweaks at it but it's not hitting the back tires enough or inconsistently ?
I assume it leaves & goes straight ?
Converters are known entities & behaving properly ?
I don't recall if it's a ladder, 4-link or leaf car, but I'd snoop around the rear suspension area...including bushings, heim joints, spring rates still good...
Posted By: DoubleD

Re: 60 ft frustration is driving me nuts - 06/15/20 05:49 PM

Its' one of three things - Converter, Converter or the Converter........................ your car is normally deadly consistent
Posted By: TRENDZ

Re: 60 ft frustration is driving me nuts - 06/15/20 06:43 PM

Does your trans allow converter pressure changes?
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/15/20 07:33 PM

We have about 15 good videos of the rear tire from the last 4 weekends.There is ZERO tire spin. I thought converter as well. So it was swapped about 20 passes ago. The trans was gutted then also. saw nothing. The 1st converter is at the shop . Getting opened up this week. Its had the issue with both converters. It's lame right at the hit. 2 pretty knowledgeable guys say they can hear it sound flat directly after the throttle is floored. The play back tach thinks that there is a peak around 3400 rpm. The tach has always done this since I've been running the car. The other thing is it will idle at 1500 with the carb speed screws backed out all the way (throttle plates closed). I'm assuming vacuum leak. Checked the carbs, carb adapter plates, and manifold lid. I'll pull the lower intake this week. It puzzles me if it is an intake leak, why it doesn't consistently run poorly? it has no adjustment for the converter pressure.
Doug
Posted By: DoubleD

Re: 60 ft frustration is driving me nuts - 06/15/20 09:19 PM

You might want to check the intake gaskets - that has been an issue I have seen three times now using the red gaskets - also check your carbs where the air adjustment screws seat into the casting - that area is really weak on the edlebrocks and any little backfire can cause cracks in the casting for some reason
Posted By: mopar97

Re: 60 ft frustration is driving me nuts - 06/15/20 09:56 PM

Originally Posted by dvw
Though we won last weekend the car hasn't been good. 60ft varies wildly. 3 different tracks. This weekend rd 1 1.40, rd 2 1.29. Its been as wide a spread as 1.29-1.46. Car leaves flat, deviously 12-16" up for 40-60foot out. What I've done to try and fix it. New M/T 10.5wx31, loosened the shocks and tightened the shocks, the fronts as many as 15 clicks. Varied tires 12-15 psi. Then with video realized there is zero tire spin . Next swapped converters, new plugs, cap, rotor, carbs apart cleaned and adjusted. Varied timing by 6 degrees. Same leave rpm, water, oil temp, intake temp. Incrementals after 60ft are spot on. Same fuel I've always run, Renegade Pro114. R/T are getting slow also. However on the practice tree they're fine. Foot brake only. Leave at 2700-3300. Eddy 750 carbs. The combo has been untouched and pretty decent for 7 years. Thoughts?
Doug


Have you checked to see if the advance in the distributor is functioning correctly? Provided that is not an issue, I too wonder about the AF screws being all the way out making no change. It does appear to be a vacuum related problem, the idea to check the intake gaskets is a good one but also the carb base and those gaskets also.
Good Luck
Posted By: Al_Alguire

Re: 60 ft frustration is driving me nuts - 06/15/20 10:24 PM

What ignition is on it, also check for vacuum leaks. Was the converter you swapped in a known piece? I would want to hear whats said from the converter guy myself. Have you noticed a change in shift recovery or flash at all? I cant see a vacuum leak causing this issue with 60's and lights and not downtrack, but who knows. I mean if its got a leak at idle and down low it would get worse up top one would think.
Posted By: TRENDZ

Re: 60 ft frustration is driving me nuts - 06/15/20 10:36 PM

With changing converters, the next thing I would check is the stator shaft. Be sure the splines are ok and that it is not able to spin in its mounting.
Never daw this with a TF, but many times on GM trans.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/16/20 12:23 AM

It does have the pink/red gaskets so that's on the list. They were replaced about 100 passes ago when the heads were off. Its MSD crank trigger, MSD 7AL 2 box, MSD 8201 pro power coil, Taylor 8mm wires NGK 8 plugs. Shift fall back with converter 1 was around 900, with converter 2 800. Converter 2 is a known piece from ATI built for a 936 hp 572, had 40 passes since new when installed. The incrementals 60/330 330/660 are nearly dead on going back to 2018. Both are 9.5 cores which outwardly appear to be the same core style. Stator shaft support was replaced about 40 passes ago. Its tight and splines are nice. Always careful with the idle screws as you say this is a known problem. My friend has a similar engine that has been dynoed at Best. Same intake with a a pair of Pro Systems 950's. Going to just switch the entire upper half with his upper and carbs.
Doug
Posted By: Al_Alguire

Re: 60 ft frustration is driving me nuts - 06/16/20 04:28 PM

Be interesting to see what you find .I just don't see the intake or carbs causing such an issue with reaction time and 60' but run great at the other end. Those kind of things generally don't clear up down track and get better.
Posted By: HardcoreB

Re: 60 ft frustration is driving me nuts - 06/17/20 01:59 PM

In the interest of stimulating feedback to ultimately help point you to an answer, I will reshare my thoughts on the forum. It is a fuel issue IMO. Maybe a signal issue at low-speed (gasket) not allowing a rich 'storm' in the plenum to compensate for the inherent lean condition with edelbrocks at the hit. What running/warm-up sequence preceded the 1.29 60ft? OR...erratic fuel pressure at low demands (assuming nothing got overlooked during recent carb inspection) Again although the edelbrocks are not going to be as fast or quick as a holley IT SURE RAN BETTER and more consistent before so, something changed. This is where having data that looked at trans rpm and fuel pressure coordinated with dual a/f widebands would help.
Posted By: Al_Alguire

Re: 60 ft frustration is driving me nuts - 06/17/20 03:11 PM

Rich at the hit is typical for anything that spends time on the brake for sure, never seen it cause an issue like he is having though. I have seen 10-1 fat conditions at the hit. A combination of lots of carb and being on the two step dropping cylinders will cause it. If it was a over rich condition a quick review of video could help confirm that, one would think if it is bad enough to cause the car to slow that much there would surely be signs of it on the video. I think it would need to be WAY fat to cause that. But ya never know I suppose. Only other way I have seen that happen is fuel dumping out the vents that will create a bog for sure and a tell tale puff of smoke, but he says it dead hooks and goes so don't see it being anything like that. Kinda like an intake leak, it should be present all the way down the track, cannot imagine that would repeat from knonw good runs with the extra air. Unless we are assuming it is "sealing" itself with more heat?

IMO most people run WAY to much fuel pressure to begin with, usually to mask an inadequate fuel system. My car is at 4.8 lbs throughout the run. Data logging might certainly help to narrow this down for sure. Would love to see a driveshaft and an acceleration graph for sure.
Posted By: HardcoreB

Re: 60 ft frustration is driving me nuts - 06/17/20 04:38 PM

Originally Posted by Al_Alguire
Rich at the hit is typical for anything that spends time on the brake for sure, never seen it cause an issue like he is having though. I have seen 10-1 fat conditions at the hit. A combination of lots of carb and being on the two step dropping cylinders will cause it. If it was a over rich condition a quick review of video could help confirm that, one would think if it is bad enough to cause the car to slow that much there would surely be signs of it on the video. I think it would need to be WAY fat to cause that. But ya never know I suppose. Only other way I have seen that happen is fuel dumping out the vents that will create a bog for sure and a tell tale puff of smoke, but he says it dead hooks and goes so don't see it being anything like that. Kinda like an intake leak, it should be present all the way down the track, cannot imagine that would repeat from knonw good runs with the extra air. Unless we are assuming it is "sealing" itself with more heat?

IMO most people run WAY to much fuel pressure to begin with, usually to mask an inadequate fuel system. My car is at 4.8 lbs throughout the run. Data logging might certainly help to narrow this down for sure. Would love to see a driveshaft and an acceleration graph for sure.


His car is always a footbraked. And was thinking it was LEAN until it got a stronger signal to the carbs. I would think down track, a localized signal loss has less affect than it would during that footbrake transition. I have seen a few manifold leaking conditions where it wouldn't be obvious there was a problem based on downtrack performance...other than idle.
Posted By: tabletop390

Re: 60 ft frustration is driving me nuts - 06/17/20 09:51 PM

We just ran into something similar on a buddy’s car and the fix believe it or not was a new master switch. The initial hit and vibration off the line and during the burnout was causing the disconnects and reconnects and making his MSD go nuts. Once he got out around 30-40 ft car settled and didn’t vibrate as much and ran like a champ. We did everything, converters, carbs, rebuilt the trans, etc.
Posted By: Sammy

Re: 60 ft frustration is driving me nuts - 06/18/20 12:03 AM

Originally Posted by tabletop390
We just ran into something similar on a buddy’s car and the fix believe it or not was a new master switch. The initial hit and vibration off the line and during the burnout was causing the disconnects and reconnects and making his MSD go nuts. Once he got out around 30-40 ft car settled and didn’t vibrate as much and ran like a champ. We did everything, converters, carbs, rebuilt the trans, etc.



How did you figure out that was the problem?
Posted By: tabletop390

Re: 60 ft frustration is driving me nuts - 06/18/20 01:03 AM

Had a programmable MSD 6 and with the laptop hooked up, you could watch the MSD go. Tried a new MSD, same problem. Damn near threw the laptop against a wall to verify it wasn’t vibration to the laptop. Started double checking connections and found the master was barely making contact. If you just turned it on it was fine. If you put a little pressure on the switch it would turn the car off. Put a new switch on, car’s been fine since. I talked to the guys at Auto Rod and they told me they see it all the time and if you don’t change your switch out every 3-5 years you’re asking for it. Told me as well that you can really see it with a Racepak but I’ve never experienced it myself.
Posted By: camastomcat

Re: 60 ft frustration is driving me nuts - 06/18/20 02:08 AM

Originally Posted by Al_Alguire
Well I would be looking hard to the converter. Reaction times obvious would change with tire slippage, but if it is dead hooking and running slow on the tree and 60' I would be looking for a converter to toss in it for sure. Might look at the trans as well but sure sounds like a converter issue to me. Just went through this on a biddies S/ST car. Pulled converter and found some fins had been knocked loose from brazing, same deal. Reaction times and 60's inconsistent down track was fine.


This! Converter sounds hurt to me too.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/18/20 09:13 AM

Easy enough to check, I'll look at it.
Doug
Posted By: 66coronet

Re: 60 ft frustration is driving me nuts - 06/18/20 02:15 PM

I have a thought.
Walk up to the core support and pull up and push down. Can you physically move the front of the car? You should be able to do this if there is enough travel in the shocks.
I had a similar issue on my car. My afco front shocks just stiffened up and quit responding to adjustments. They had always been flawless and you know how my car leaves.. One race I couldnt hit the tree and my 60s fell off. I fought it for several events. one day I grabbed the front of the car and tried to bounce it and I could not move the car.

I backed the top nut way off and could move the car. When I got home i pulled them off and put an old set of comp 3 ways on it at the tightest setting and it was night and day difference.
Now I have good shocks back on the car but that set bound up for some reason.

Its easy to check and eliminate as an issue.
Posted By: Tommy D

Re: 60 ft frustration is driving me nuts - 06/18/20 03:56 PM

Doug, You said in your original post that you won the race...congrats! What were the ET's on the passes that were all stable after the 60'? If the ET and MPH increments are close, then a comment earlier about where you are tripping the beams (60') sounds very logical. I never had an issue with wheelies, so I'm a rookie there, but makes sense. We run Eddy 750's on an original intake in "FRUSTRATION". I also have an original set of Carter 750's (not MW). The Eddy's from new were nearly impossible to adjust the idle. Found out the throttle shafts on both carbs were really loose. Had to have them bushed. It ultimately got so bad that the car would idle at 2-2500 after a pass. Good luck.

Attached picture Frustration ready for 2018.JPG
Posted By: Tommy D

Re: 60 ft frustration is driving me nuts - 06/18/20 03:58 PM

No idea why the photo was posted upside down. Name of the car fits!
Posted By: second 70

Re: 60 ft frustration is driving me nuts - 06/18/20 04:13 PM

I had problems with mine only at launch and found out it was something in the tach screwing up the msd.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/18/20 06:03 PM

Just talked to Perfect Converter. Converter is undamaged and has a mechanical diode along with a steel stator. Good parts. So it'll get a couple toringtons and back together. I should've been clearer in my time slip comparison. The incremental splits match up . The actual ET is slow by at least what the 60 fell off . Example, last week 1.32/9.09, 1.40/9.17. Shocks will get pulled and dynoed.
Doug
Posted By: Tommy D

Re: 60 ft frustration is driving me nuts - 06/18/20 07:11 PM

Makes sense. You did say you put new slicks on the car. Were they the same brand and compound that you've run in the past? I've seen 60' times go away when the slicks stop doing their job. A car as fast and violent as your's will likely eat up sidewalls pretty quickly. Sometimes it's good to have a slow race car...like me; ) Still plenty of problems, but certainly cheaper to fix. Good luck. When is your next race?
Posted By: JD Dart

Re: 60 ft frustration is driving me nuts - 06/18/20 09:34 PM

I'm not a fan of mechanical diode had one go bad you could see on racepak, when it went bad, 60' was all over the place. Sent the converter back they said it's OK. Ask them to change the stall by 300 hundred looser Long story short I didn't put that converter back in for a few years then went to a bracket final in Boise and thought I'll give it a try should work great for higher altitude. It did on the 1st pass then broke on the second pass would want to push me while staging but it was done lost 7-9 mph and ET went to crap. Sent it back again this time they changed the diode and I sold that convertor and will never use them again. I will only run spragless nothing to go wrong but the normal laying over fins.
You don't have racepak or any data recorder on your car?
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/19/20 09:12 AM

Tires were swapped at the end of the years when I started noticing the problem. Since this issue has occurred the video shows zero tire slip. Also has done it now with 2 different brand converters. it will be getting a data logger.
Doug
Posted By: TRENDZ

Re: 60 ft frustration is driving me nuts - 06/19/20 11:32 AM

Originally Posted by tabletop390
We just ran into something similar on a buddy’s car and the fix believe it or not was a new master switch. The initial hit and vibration off the line and during the burnout was causing the disconnects and reconnects and making his MSD go nuts. Once he got out around 30-40 ft car settled and didn’t vibrate as much and ran like a champ. We did everything, converters, carbs, rebuilt the trans, etc.


Don’t discount this. It has happened to me also. My car was EFI. The logger was the EFI. When this happened, it would get a corrupt the log, so finding the issue was difficult. The engine wouldn’t die, nothing went 100% dead, but everything electrical would glitch. Would not believe it if it hadn’t happened to me.
Posted By: n20mstr

Re: 60 ft frustration is driving me nuts - 06/19/20 01:19 PM

Originally Posted by dvw
Tires were swapped at the end of the years when I started noticing the problem. Since this issue has occurred the video shows zero tire slip. Also has done it now with 2 different brand converters. it will be getting a data logger.
Doug


I know that some NSS rules say no data loggers, But honestly I would hide it in the car if I had to. At the minimum get yourself a Racepak Sportsman. Best thing you will ever do, and your fast car will become even faster ! ! I couldn't race without one now LOL
Posted By: Bad340fish

Re: 60 ft frustration is driving me nuts - 06/19/20 02:07 PM

Originally Posted by TRENDZ
Originally Posted by tabletop390
We just ran into something similar on a buddy’s car and the fix believe it or not was a new master switch. The initial hit and vibration off the line and during the burnout was causing the disconnects and reconnects and making his MSD go nuts. Once he got out around 30-40 ft car settled and didn’t vibrate as much and ran like a champ. We did everything, converters, carbs, rebuilt the trans, etc.


Don’t discount this. It has happened to me also. My car was EFI. The logger was the EFI. When this happened, it would get a corrupt the log, so finding the issue was difficult. The engine wouldn’t die, nothing went 100% dead, but everything electrical would glitch. Would not believe it if it hadn’t happened to me.


I had a friend with a backfire problem on a nitrous mustang. It would backfire at the hit no matter what we did. The problem ended up being a bad connection at the master switch. We found the problem real quick at the first night race because the taillights flashed, then it backfired and moved out. We fixed the connection and he promptly dang near drug the bumper off of it on the next pass when everything worked as it should.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/19/20 02:52 PM

Here's my plan. Pull the shocks and run them over to my shock guy. He has dyno sheets. We'll see if they match up. New 16volt battery and upgrade alternator to 16v. Going to swap my buddy's intake top and pro systems 950 carbs before track testing. Pull the lower intake to inspect gaskets. This would be a time consuming swap at the track. Parts I will bring; a bolt on bypass for the master switch, spare coil, spare MSD box, spare crank pick up, new can of fuel. Will be purchasing a data logger. It will have to be removable for NMCA. That's just going to take a little longer than my current 3 week window before our next race.
Doug
Posted By: Al_Alguire

Re: 60 ft frustration is driving me nuts - 06/19/20 05:11 PM

Jess echoes my sentiments on mechanical diode converters. Been there done that. As for converter guys saying they found nothing been there done that more than once as well. not saying that's happening but seen it happen more than once. Just had a buddy wipe out the thrust in his S/ST car due to a converter(big name shop), but they told him all was well. Oddle enough came back with a billet fro Kinda like finding a problem with and MSD unit that wont start a car yet they find nothing and works like a champ when it comes back smile

Plenty of validity to the cut off switch deal, seen that happen a number of times. Especially on older switches or hard leaving cars. Charging system voltage issue in general on the same style car. We had an alternator issue on the dragster that was causing the car to shut off when the shifter was activated. Car was still deadly consistent but we could not figure it out. Til it was on a single and we heard it shut off. The alternator was working just not enough to cover up the draw of the solenoid. If we had a date logger would have been much easier to diagnose. New battery and alternator and it was good to go.

Like I say be interested to see what you ultimately find.
Posted By: A727Tflite

Re: 60 ft frustration is driving me nuts - 06/19/20 06:39 PM

First thing I would swap would be the MSD box.
One of our cars back in the day lost a tenth over time, car was running low tens. Forgot what led us to it but replacing the box brought it to life.

Two converters - same result, eliminates that I think.
Posted By: B3422W5

Re: 60 ft frustration is driving me nuts - 06/19/20 07:27 PM

Originally Posted by Transman
First thing I would swap would be the MSD box.
One of our cars back in the day lost a tenth over time, car was running low tens. Forgot what led us to it but replacing the box brought it to life.

Two converters - same result, eliminates that I think.





Had a bad digital 6 box years ago that slowed my car down 1/2 second, but not on every pass. Maybe once every three or four passes.
Set up to run 10 flat, would run 10.50ish when it occurred.
Chased everything most of a season before swapping the box out and finally fixing it.
Good thought, could well be the box.. capable of wierd issues
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 06/19/20 09:46 PM

Converter #1 has the diode. Dont know about #2 . It is an ATI unit. Not inconcievable that 2 converters could be randomly bad. But I think it would be unlikely. Converter #1 has been really good for 3 years
We'll see soon.

Doug
Posted By: Leigh

Re: 60 ft frustration is driving me nuts - 06/19/20 10:22 PM

Having chased the same dog, and frankly, still waiting to see if I know the reason, and actually holding a diode in hand, they either work or destroy themselves. Mine wore over 15 years, but still worked. I’m trying to get back together, to verify a fuel delivery suction issue. Good luck!
Posted By: A727Tflite

Re: 60 ft frustration is driving me nuts - 06/19/20 11:05 PM

Would be interesting to see how they checked the stator overrunning clutch. Checking it by hand could allow a bad unit to pass inspection. Unless you apply enough torque it’s conceivable that you could have a stator cam that’s lost it’s spline lock.

I have seen that in diesel converters, they will pass the “finger test” we spoke of but will fail the bench test. We are talking hundreds of pounds to test the unit on the bench.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/03/20 10:47 AM

the past couple of weeks i've been working on the car. Reconfigured the alternator to 16 volt, new alternator wiring, modified the battery tray for the XM battery. Pulled all 4 shocks. The RF Afco was leaking and the compression adjuster doesn't change dampening so its getting repaired. The rear Konis have one shock that is much stiffer in compression than the other at the same setting. Its getting checked as well. took the sticking front calipers apart and rebuilt them. New front tires. Built a data recorder with Inovate LC 2, SSI 4 and a pocket logger. Also added an accelerometer to measure Gs. It has to be removable as NMCA doesn't allow it in N/SS. @ connectors, O2 sensor and Mil spec screw on connector. Velcro holds it to the bracket. Carb swap is still coming. Have new barrel of C-14. Testing soon.
Doug

Attached picture logger 3.jpg
Attached picture logger 2.jpg
Attached picture logger 1.jpg
Posted By: tboomer

Re: 60 ft frustration is driving me nuts - 07/03/20 10:52 AM

Good luck Doug! Quality work as usual! up
Posted By: Harry's Taxi 2

Re: 60 ft frustration is driving me nuts - 07/03/20 11:31 AM

What accelerometer did you use?
Posted By: Bad340fish

Re: 60 ft frustration is driving me nuts - 07/03/20 11:38 AM

Originally Posted by Harry's Taxi 2
What accelerometer did you use?


I was just about to ask as well. They is some really cheap ones out there if you have some kind of logging device to wire them into it. I keep wanting to add one to my EFI for logging but I haven't yet.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/03/20 11:48 AM

Used this for the Accelerometer Its the small bord on top of the SSI 4. Less than $20

https://www.adafruit.com/product/163

This sensor picks up off the parking pawl gear in the trans. Attached thru a welded bung on the tail shaft housing.

https://www.verical.com/pd/cherry-e...6n6jVWT4nGzxW84eqst18Ry-pSRYPtRoCSp8QAvD

Doug

Attached File
Posted By: Bad340fish

Re: 60 ft frustration is driving me nuts - 07/03/20 12:06 PM

Originally Posted by dvw
Used this for the Accelerometer Its the small bord on top of the SSI 4. Less than $20

https://www.adafruit.com/product/163

This sensor picks up off the parking pawl gear in the trans. Attached thru a welded bung on the tail shaft housing.

https://www.verical.com/pd/cherry-e...6n6jVWT4nGzxW84eqst18Ry-pSRYPtRoCSp8QAvD

Doug


Thanks that is one I have had on the list. if I have another 5V input I will add one of these soon.

I have a different Cherry Hall sensor than that but they have been rock solid. I run them for my Crank Sensor, Driveshaft sensor, and front wheel speed sensor.
Posted By: Harry's Taxi 2

Re: 60 ft frustration is driving me nuts - 07/08/20 11:14 AM

Originally Posted by dvw
the past couple of weeks i've been working on the car. Reconfigured the alternator to 16 volt, new alternator wiring, modified the battery tray for the XM battery. Pulled all 4 shocks. The RF Afco was leaking and the compression adjuster doesn't change dampening so its getting repaired. The rear Konis have one shock that is much stiffer in compression than the other at the same setting. Its getting checked as well. took the sticking front calipers apart and rebuilt them. New front tires. Built a data recorder with Inovate LC 2, SSI 4 and a pocket logger. Also added an accelerometer to measure Gs. It has to be removable as NMCA doesn't allow it in N/SS. @ connectors, O2 sensor and Mil spec screw on connector. Velcro holds it to the bracket. Carb swap is still coming. Have new barrel of C-14. Testing soon.
Doug


What's the need for a resistor(if that's what that is) between input and output voltage? I'm going to add the same accelerometer to my LM2 (thanks for the idea by the way) and the wiring diagram doesn't show a resistor.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/09/20 10:35 AM

A pull up resistor is speced with the accellerometer. The give you the spec based on your input voltage 1K for 5 volt, 2.4K for 12 volt etc.
Doug
Posted By: Harry's Taxi 2

Re: 60 ft frustration is driving me nuts - 07/09/20 02:16 PM

Originally Posted by dvw
A pull up resistor is speced with the accellerometer. The give you the spec based on your input voltage 1K for 5 volt, 2.4K for 12 volt etc.
Doug


Thank you....I missed that when I ordered one.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/18/20 12:11 PM

Further updates. Had the Willwood Calipers apart twice. Measured the rotors, bores the pistons. Polished everything with 1000 grit. They still don't retract as I would like but are better. XS 16v Battery is installed. The regulator swap in the alternator works great. Front shocks are repaired and installed. Decided to upgrade the 20 year old rear Koni shocks to Afco big guns. They should be here by Tuesday. Data logger records A/F, RPM, and G's. Down loads correctly. How ever we're having an issue with the driveshaft speed sensor reading. Found a slight intake leak on #2/4. So that's fixed as well. Fixed a minor trans leak at the park cable housing. Hope to test this week.
Doug
Posted By: rickraw

Re: 60 ft frustration is driving me nuts - 07/18/20 04:12 PM

Those are stainless pucks, buff them on a compound wheel till they look like chrome. I had the same problem the demon.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/18/20 05:24 PM

I did.
Doug
Posted By: nss guy

Re: 60 ft frustration is driving me nuts - 07/18/20 08:32 PM

supposedly they are 2 different O-rings for them, square and round. I think the round are suppose to help with return. Something to check out
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/18/20 09:18 PM

From what I could research they claim the square are better. I contacted a guy from Willwood. Sent him all the info. I've heard nothing. Russ Konkowski, Rick Newmeyer, Casey Fauss-Johnson, John Frazier all having the same issue on there N/SS cars.
Doug
Posted By: Leigh

Re: 60 ft frustration is driving me nuts - 07/18/20 09:36 PM

Hopefully not the same “tech guy”, that told me their new, solid rotors had .012 runout from sitting in the sealed box. Never again.
Posted By: nss guy

Re: 60 ft frustration is driving me nuts - 07/18/20 10:53 PM

From classracer

Attached picture 52F5B02E-3B91-4875-8823-0AB4CC4CA086.png
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/19/20 12:17 PM

The Willwood spacers are .030". The calipers are spaced as close to center as you can get within .030". The pad wear is square to the rotor. The other day when we talked, the Willwood tech he made no mention of using round caliper seals. I wonder why? He also has not returned my E-Mail since. Its been 5 days. The area outside of the seal was relieved and polished along with the pistons. Now at least you can move the rotor by grabbing the wheel studs. It doesn't spin but at least it moves. Waiting on the shocks. So we'll see when its on the ground.
Doug
Posted By: BANDIT

Re: 60 ft frustration is driving me nuts - 07/19/20 01:51 PM

Yeah, Wilwood customer service people don’t seem to be on top of call or email follow up. I assumed they were still out or low staffed cause of the COVID thing. Maybe....
I know you said you had changed tires, and not knowing much about your car, I’m kinda shooting in the dark, but. How heavy is car, have you experimented with tire pressures to see if maybe you can get more wheel speed out of the hole? First 2 weekends out with my dragster this year, same set up as I ended last year with, my reaction times and 60 foots were all over the place. Put new tires on, still slow on 60 ft, so dropped pressure by 1/2 lb total and Sunday, I had no worse than a .015 reaction time, less than .001 difference per lane, and cut a .000 in finals to win.
Had same frustration with my Avenger, spent waaay more time and money before finally putting tires on it to solve that. The Avenger is a 4 link and the dragster is a slip-joint, but tire pressure and condition has caused me more frustration and cost more money than I care to admit. Tires every 90 to a 100 passes is gonna be normal any more for me. Jim
Posted By: Bad340fish

Re: 60 ft frustration is driving me nuts - 07/19/20 02:20 PM

Originally Posted by dvw
Further updates. Had the Willwood Calipers apart twice. Measured the rotors, bores the pistons. Polished everything with 1000 grit. They still don't retract as I would like but are better. XS 16v Battery is installed. The regulator swap in the alternator works great. Front shocks are repaired and installed. Decided to upgrade the 20 year old rear Koni shocks to Afco big guns. They should be here by Tuesday. Data logger records A/F, RPM, and G's. Down loads correctly. How ever we're having an issue with the driveshaft speed sensor reading. Found a slight intake leak on #2/4. So that's fixed as well. Fixed a minor trans leak at the park cable housing. Hope to test this week.
Doug


I assume you have one already but my Cherry hall effect sensor that is on my driveshaft requires a pull-up resistor. Also how many teeth does your reluctor wheel have on it? I have heard issues of some systems not being able to read them if they have to many teeth, should still work at low RPM though if that was the case.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/19/20 11:55 PM

So to answer both questions. One rear shock locked up intermittently when it was compressed in the vice. So far its the only smoking gun. Thus the new shocks. The sensor has the pull up resistor. the park gear has 22 teeth. We use the same sensor and setup on my sons turbo car. Though his logger is AEM. Maybe its entirely possible I didn't spin the tires fast enough. Cant put it in gear yet since there are no shocks. Good thing the fuel pressure got tested. Up to 9 psi from 6 psi. Turned the front regulator 3 full turns, no change. Fabbed up a pressure tester at the regulator inlet. Put the 12 volt battery back in the car. The Product Engineering pump output was 33psi. With the 16 volt battery it was 38psi. Turned the bypass regulator at the pump back 2 1/2 turns, 33psi.
Doug
Posted By: JERICOGTX

Re: 60 ft frustration is driving me nuts - 07/20/20 02:22 AM

Doug, what is your driveshaft sensor issue? I have a RacePak Sportsman, and am also having issues with it.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/20/20 10:37 AM

When the SSI4 is set up to read Hertz we see no signal on Logworks. If you lie to Logworks and tell it it's a 0-5volt signal then the gauge on Logworks jumps around. So there is something there. Calling Inovate is like talking to the wall. "They say there guy will get back to us". No call or Email from them. Over a week. Once the shocks are here I'll put into gear and get some rpm into it and see.
Doug
Posted By: TRENDZ

Re: 60 ft frustration is driving me nuts - 07/20/20 11:57 AM

Are you using a hall, a mag, or an MR sensor?
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/20/20 01:49 PM

Hall effect, ZF GS 100201
Doug
Posted By: Al_Alguire

Re: 60 ft frustration is driving me nuts - 07/20/20 02:13 PM

Well the shock having issues when compressed is NOT helping for sure. Compression is used to keep the tire planted after initial hit so entirely possible you found the issue. You will find out soon enough. As for Wilwood I was always told to use the square cut o ring, but I have found no matter which you use they will eventually be right back to hanging up again.
Posted By: Bad340fish

Re: 60 ft frustration is driving me nuts - 07/20/20 02:23 PM

Originally Posted by dvw
Hall effect, ZF GS 100201
Doug


With that sensor it should pick up at very low speeds. I have one on one of my front wheel that reads off the wheel studs, it reads just fine just by spinning it by hand. With 22 teeth and assuming you are turning the rear tires by hand it should read no problem.
Posted By: TRENDZ

Re: 60 ft frustration is driving me nuts - 07/20/20 03:10 PM

Been a while since Ive used logworks, but isn’t there a “speed” selection? I do agree that it should work with freq. Are you using 5v reference or 12?
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/23/20 12:12 AM

First off It appears that the brakes are repaired. There were some shims supplied with a set of pads that were installed a while ago. They wouldn't fit behind the new pads , no room. They cant be more than .060" thick. I decided now that pads had a little wear to try them. The backing plate of the pad has a few 1/2"? holes. Maybe something to due with the bonding ? anyway installed the shims and you can actually spin the wheels. To the driveshaft. Yes there is a speed selection.feeding the sensor with 5 volts. My son (Dizuster here) is bringing an oscilloscope tomorrow to try and troubleshoot the driveshaft issue. New Afco big guns are on. No time to test. I'm going to go out and race it Saturday. Hopefully my guess at the shock settings is close. We'll see.
Doug
Posted By: merpar

Re: 60 ft frustration is driving me nuts - 07/25/20 12:09 AM

I got into this a little late didn't read all the post's. Myself my motto is KISS= keep it simple stupid. I always look at myself first. First thing I see is launch RPM. I raced for years foot braking and found that you need that full shot of fuel on the launch. Be consistent on your rpm, Meaning, don't leave at 2700 one time then 3300 the next. I ran a holley and would leave at 2000 rpm to get the full excellerator pump shot. Made a huge difference if I changed. I hope it is something simple for you. Its usually cheaper.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/25/20 02:21 AM

We vary reaction time with starting line RPM. So it normally leaves between 2800-3200. Data logger still partial function. O2 is pegged full lean. Driveshaft sensor is sending a clear pulse. We watched it on an oscilloscope last night. Racing tomorrow with zero testing.
Doug
Posted By: jwb123

Re: 60 ft frustration is driving me nuts - 07/25/20 08:42 PM

Originally Posted by nss guy
supposedly they are 2 different O-rings for them, square and round. I think the round are suppose to help with return. Something to check out


The square ones are supposed to pull the pistons back slightly when you release the brakes. Round O-rings will leave the pistons where they are when released.
Posted By: dvw

Re: 60 ft frustration is driving me nuts - 07/26/20 10:48 AM

Ran the car yesterday. Track prep was so so. I should've checked track temp but didnt. Air wasnt great. 90 degrees and humid.water grains over 100. That being said the car was pretty good. Took a guess at the initial shock settings and made 2 sets of adjustments. Since we were in eliminations didnt want to make to many changes. Car was very good. The new Afco rear shocks were the key. Obiviously the old rear shocks had an issue. Ran 60 ft within .01 all day. 60 ft is still slower than I'd like but I really believe part of that is the Edelbrock carbs lack of transition to the main circuit. That will be the next issue to attack once the data logger function. Car followed the weather station predictions with in less than .01 for 5 out of 6 passes. Got out of the groove in rd 4. Fell off .02. Lost by .005
Doug
Posted By: tboomer

Re: 60 ft frustration is driving me nuts - 07/27/20 10:04 AM

I'm glad you are getting it figured out Doug! Well done! up
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