There was an earlier (2 weeks ago) thread regarding the possibility that GM programmed the PCM with key variables, which when looked at together, might indicate that torque is exceeding 350 ft lbs in the 02 Z.
The concern was that the active handling system would take over (regardless of being switched on or off). I believe a GM tech responded he had heard about this but had not had a car come in yet to evaluate.
Anybody have any additional details?

 

I am not certain but from what I have read the auto trans vetts have torque management but the 02Z has wheel hop alragrithm. I don't think it's the same thing. Anyway at the track whatever the 02 has, it does not seem to be very intrusive to my sop. Ric

 

Torque management is a completely separate function that operates independently of traction control, and torque management only applies to A4 equipped cars, not M5 models.

Duke

 

We have found even switching the active handling off and the traction control off that there is still "some" torque management with both automatic and 6 speed cars, we are working on this problem as we speak. ;)

 

SWCDuke
How are you, knowing you have a lot of knowledge can you help me. I have an 02Z and still am experiencing wheel hop on high rev shifts. Yes they are powershifts but I thought the alragritham is supposed to handle that. I have not tried a burnout from a stopped position yet. Might there be a problem with my car ??? By the way this happens with or without all traction controls on. Hope you can help !!!

 

jrd, Try a differant tire presure to adjust the car to your driveing style. Ric

 

Powershifter, what do you suggest ??? 25lbs 28lbs. Any others try tire pressure to cure the problem ???

 

jrd, It depends, for my driveing style I like 28 in the F1's but if I were to get hop on my shift I would change presure until I found an improvement. I would allso try changeing my shift point from my usuel 62-6300 shifts looking for better result. Every car is differant, and track conditions are constantly changeing. Experiment and you will fined something that works for YOU. Ric

 

My 2002 Z06 drops the timing to 17 degrees when the torque gets to 350 lb ft at the rear wheels. It is progressive, smooth and happens very fast. It doesn't matter if you have AH/TC on or off. Any scanner will show you where the torque management is set and a program like LS1 Edit is capable of changing the settings.

 

Ric, I'm an old dragracer -- I used to run a 70 GTX 440 which I built to over 500hp. It had a racing automatic, and I ran a 12.3 best 1/4 mile. Now I'm back with a 2002 ZO6. I've added a vortex power duct and CR intake w k&n filters. My dream is to run in the 11s on stock F1s. So, I'm a novice with the stick shift, and my question is what is the optimum launch strategy for a non power-shifter. Front/rear tire pressure? Launch RPM (after burnout)? Shift RPM in 2nd, 3rd and 4th. Octane 50/50 mix of 93 and 100? How much fuel to carry -- 1/2 tank?

 

I'm not aware that the '02 Z06 has an "axle hop" algorithm. I believe that in competition mode (TC off) there is no electronic assist of any kind for traction. There was a change in rear shock valving for '02 which mitigated the "freeway hop" phenomenon, but I don't know if the change mitigates the wheel hop problem under heavy acceleration.

I had a '01 Z06 press car early last year for a weekend and found that getting a clean launch from a dead stop is a delicate balance between hop and lighting up the tires. Depending on available traction, a launch from 1500 to 2000 by simultaneously dropping the clutch and throttle is the basic method to start with. Out of a half dozen tries I got it right a couple of times, and it's like being shot out of a gun!

I never power shifted it - against my philosophy even if it isn't my car, but I found that I could bang off lift throttle shifts as fast as my hands and feet could move. If you power shift the engine just leans on the limiter while the clutch is disengaged. Then as you let out the clutch the engine comes off the limiter, but is tuning 6500 at WOT and the clutch has to drag the revs down to about 4500 for full clutch engagement. This is obviously tough on the clutch and the shock load is tough on the drivetrain and tends to break the tires loose.

Try some lift throttle shifts - as fast as you can - and see if the situation improves. Powershifting IMO doesn't really improve performance (and may even reduce acceleration performance), and it can tear up the clutch and drivetrain pretty quickly.

BTW, wheel hop is a problem on virtually all very high powered cars. It appears that rear shock valving to control hop is very different from valving to aid ride and handling, so they sacrifice some drag racing performance; but remember, the Z06 is a sports car, so the emphasis it to maximize handlling within some reasonable ride boundary of ride quality.

Duke

 

Duke. Thanks... I misundestood the algraritham to be for launch wheel hop not road bumps. With the difference now understood I see the problem. Good suggestions on shifting and launch. Will try it and get back to all.
Thanks again.........

 

Bob, Depending on conditions with the F1' the launch That's working for me is between 25-2800, roll into the throtle smothly and SLOWLY. I can tell you power shifting works and produces better et's on the track.If it's done properly at 62-6300 you will not touch the limiter. I would recomend the same 63-6400 if you want to speed shift lifting the throtle on the shifts. I alway spin the tire to make shure it's clean but have seen no differance heating the F1's. We have 94 sunoco at the pumps, I don't think more octan than that will help with the stock programing but I never persued it. I try to get to the track with 1/4 tank, lighter is better,I have had no fuel delivery problems down to under 1galon. Good luck at the track!! And have FUN!! Ric

 

SWCDUKE, Check out Hib H's article in GM High Tech Performance Mag. He quotes Jules J(sp) corvette enginer on the wheel hop algrothim. Ric

 

I thought it seemed like traction control was on when I get wheel hop. And it does not matter if I have it in Comp mode or off. But only under the right conditions does it kick in.

 

Ric,
Thanks for the information. I just don't want to embarrass myself at the track. It's going to take some practice. I tried some launches at normal tire pressure in a parking lot. I came out at 2800 and rolled into the accelerator. The noise and action surprised me and I hit the rev limiter the first time after leaving about 50 feet of rubber. It broke loose in second too. The second time I tried to concentrate more and made the first to second shift at about 6000. It broke loose a little but hooked up nicely. It seemed that both times I had some wheel hop, so tire pressure will be an important factor. What front/rear pressures do you use? Also, it seems that ever time I add something (the Vortex power duct) about three hours later, the check engine light comes on. Should I have it reprogrammed again, or will the chip learn and adjust? Thanks again for your help.

Bob W