Pulling timing during launch?

[apd252]

So I have this headache often when launching at the track. Car is at operating temp, half tank of fuel, traction control is totally off and the car is not spinning. When I launch it feels like it is pulling timing. There is absolutely no tire spin and as soon as I shift to 2nd its fine. It is so bad that 2nd pulls harder and runs out faster than 1st. I have tried launching with rpm between 4000 and 5500. Just keeps happening. When it doesn't act up I can pull low 1.6 60' times but today I pulled 2.0x 60' times.

It's not only happening to me but, to atleast 3 of my friends as well.

Anyone know if there is a safety measure in our cars that makes this happen?

I have asked this before but no one had an answer. I was praying someone might have some new light to shine on this.

 

[slagburn]

Have you datalogged to verify the amount of timing?

 

[apd252]

No. I haven't been able to. I would imagine if it is pulling timing in first because of too much timing that it would do it in all gears.

My other friends have everything from stock to boosted that this is happening to as well.

 

[slagburn]

Datalogs are your friend. I do know that with a returnless fuel system you can get a momentary lean spike at the start of each gear, this may be enough to piss off the knock sensors.

 

[stang8psi]

are you on a factory clutch? it could be that!

but like others have said datalog it !

 

[apd252]

Yes. I am on the factory clutch. Its still in good shape. My friends 2012 is on a twin disc doing the same thing as mine with the launch.

I do need to datalog at the track. Its just so hard with how flakey the software is.

 

[BAKnBLK2010]

I have read about your issue on the 2011 up manual cars many times but I have yet to hear the cause or fix for the issue. My 2011 manual car didn't have this issue. There are a couple more threads on here asking the same question but nobody has said what fixed the issue that I can see.

 

[apd252]

I have read about your issue on the 2011 up manual cars many times but I have yet to hear the cause or fix for the issue. My 2011 manual car didn't have this issue. There are a couple more threads on here asking the same question but nobody has said what fixed the issue that I can see.

We know ford employees read this forum as well. Apparently they dont have an answer either.

 

[86GT351]

BAsed on your signature, I would #1 DATALOG. Multiple runs also. #2 get the files to Lund to look and see what is happening. They will help get you situated!

 

[DTony]

As mentioned you need to data log. It sounds to me like a torque managment issue in the tune.

 

[apd252]

I think I'm screwed till next year for datalogging. Only a few race days left this season and I work every one.

Still hoping someone has had this problem and found a solution and lets me know.

 

[filtercharger]

Does it feel like it falls on its face at launch, then takes off hard? if yes, I had the same problem with mine and Ken from Kenne Bell found out that there is a sensor or parameter that detects clutch slippage, meaning, something is telling the ECU that the clutch is spinning quicker that the rest of the drivetrain when fully engaged, like DTony mentioned, a torque management issue. He was able to fix it on the tune.

 

[apd252]

Does it feel like it falls on its face at launch, then takes off hard? if yes, I had the same problem with mine and Ken from Kenne Bell found out that there is a sensor or parameter that detects clutch slippage, meaning, something is telling the ECU that the clutch is spinning quicker that the rest of the drivetrain when fully engaged, like DTony mentioned, a torque management issue. He was able to fix it on the tune.

That is exactly what it does. It doesnt take off hard until I shift to 2nd. I will let kenb know. Thanks man.

 

[Five Oh Brian]

My '11 GT was doing this all season. It would fall on its face in 1st gear and not regain power until the very end of first gear and second would hit hard. If I launched at idle, it wouldn't always do this, but when it did my 60's would suck, as would my whole run.

With a lot of traction and launching from a dead stop, there seems to be too much load on the engine and the ECU is pulling a LOT of timing to prevent detonation. 2 weeks ago - at the advice of a seasoned racer - I replaced my 3.73 gears with 4.56 gears to lessen the load on the car at launch. This cured my launch 100% and now it launches hard (1.68 to 1.75 sixty foots). However, I now have to shift into 5th gear, but it was worth it to get the damn car to launch properly!

I have a thread running about this here. Perhaps it will help you somehow.

 

[apd252]

My '11 GT was doing this all season. It would fall on its face in 1st gear and not regain power until the very end of first gear and second would hit hard. If I launched at idle, it wouldn't always do this, but when it did my 60's would suck, as would my whole run.

With a lot of traction and launching from a dead stop, there seems to be too much load on the engine and the ECU is pulling a LOT of timing to prevent detonation. 2 weeks ago - at the advice of a seasoned racer - I replaced my 3.73 gears with 4.56 gears to lessen the load on the car at launch. This cured my launch 100% and now it launches hard (1.68 to 1.75 sixty foots). However, I now have to shift into 5th gear, but it was worth it to get the damn car to launch properly!

I have a thread running about this here. Perhaps it will help you somehow.

Thanks. I'll read up as soon as I have time tomorrow.

 

[filtercharger]

I believe Ken and Jon communicate often about this type of issues and other remedies, I'm sure if you contact Jon he'll have a fix for it! After Ken retuned my car, I was able to launch hard and no issues, I'm running the stock clutch, 3.73 gears and 28" Hoosier full slicks, so far best 60ft is 1.55, and clutch is just fine!

 

[Falkinman]

Filtercharger, are you hitting the rev limit before the traps in 4th? What rpm's are you shifting at and crossing at with the 28" slicks? With my stock tires and 3.73's I'm hitting it before the traps. What are your mods and track times?

 

[RSKtakR]

OP, I know you said your traction control was totally off, so Its safe to assume that when you say "totally off" you have held the brake pedal and the TC button for 10 seconds after the key is turned on (and not turned off again) so the entire system is TOTALLY off right?

 

[filtercharger]

Filtercharger, are you hitting the rev limit before the traps in 4th? What rpm's are you shifting at and crossing at with the 28" slicks? With my stock tires and 3.73's I'm hitting it before the traps. What are your mods and track times?

Hey bro! yes I was hitting the limiter and having to shift into 5th right before the stripe, that was with 26" tall slicks and the stock limiter setting, which I think is 6800k. With the 28" tall slicks and the limiter set at 7100k, I pass the stripe in 4th and don't hit the limiter! I usually shift right at 6900k. The car has a Kenne Bell 2.8LC, Pypes cat back exhaust and Barton Shifter. Is set at 9psi because of the water down 91 octane gas here in Cali, it still has cats and stock h-pipe. Best time is 11.30 and best mph is 123 so far, but Ken has optimized the tune recently, so it shoud be a little quicker now!

 

[Falkinman]

I'm still on the stock tune. I thought the stock limit was 7,000 though. Now I'm wondering how tall the stock 19" p-zeros are. I'm thinking they're taller than 26" but I'm not positive. I need to get some drag tires although I'm getting 1.8 sixty foot times without them. I'm absolutely incinerating the tires on the 1-2 shift and that's gotta be slowing me down alot. It would be nice to get a slightly taller tire while I'm at it so I can complete a pass without hitting the limiter. Gotta love my Barton shifter! I've also got GT500 mufflers and lower control arms to help with the wheel hop. I like your sixty foot times!