C8gofast

In Race 2 , I have yet to find a mode that does not retard the throttle when coming out of a fairly sharp corner.
I tried:
Track only with TC and ESC off
Race 2 with TC and ESC off
Race 2 in Z mode with PTM off.
It sucks.

For example coming out of the corkscrew at Barber’s, the throttle is on the floorboard and nothing. I have to straighten the wheel completely for a split second before throttle kicks in. Same thing on a few turns at NOLA.

The computer is not happy and stability control kicks in even though I have it turned off.

Any ideas?

Michael A

I'm interested in hearing more about this. It seems like if you turn ESC and TC off, there shouldn't be any power reduction. Did you try ESC, TC, and PTM off?

C8gofast

Yes, I tried that as well. Someone told me that even if you have TC and ESC off they still engage at 25% . Seems to be true.

RapidC84B

You've tried the car in track mode with everything off? No PTM, just hold it down and turn ESC/TCS completely off? That was going to be my next try at VIR in a couple weeks. In RACE2 it still cuts power hard on the 2-3 upshift out of T1. I ended up manually shifting it to short shift there.

C8gofast

I’ll try that Monday at Barber’s. I’ll be at Road Atlanta this weekend, but that track does not have sharp enough turns to cut power.

z28lt1

Yes, go to track mode on the selector, do not go into PTM, just hold the button down for like 10 seconds and everything should be off. If that is really full off or not I guess we'll find out.

Incidentally, in the Ask Tadge section, he once posted the below. No idea how true it is not, but at least GM thinks it is (and I suspect for these special corners it isn't):

We find that the calibration settings that achieve the fastest lap times often result in expert drivers feeling like they are being held back slightly on corner exit. Most of the time that extra little bit of slip that an expert driver wants is over the traction peak of the tire and may feel good but is wasting forward acceleration. The restrictive feeling is not there as a safety net, rather, it’s as close as we can operate to the peak capability of the tire in a robust way.

RapidC84B

In general I agree w/ Tadge, but in certain instances the car is slamming the throttle shut hard like old school C5 TCS.

Electron Mike

Here is what I do, and it seems to be off to me as it will slide on track: Z mode set to full kill on everything except PTM off, then press and hold TC button until it says ESC off and has both the TC light and ESC light on. Is this what you tried?

RapidC84B

That turns everything off... same as entering track mode, then NOT engaging PTM, then holding button down until ESC/TCS are fully off. Car "should" be fully yours at that point.

Electron Mike

Agree. I don't think either of these two he wrote are really possible, so not sure what he did for track only TC and ESC off.

"Race 2 with TC and ESC off" - I don't think TC is off in Race 2, I still get power cut.
"Race 2 in Z mode with PTM off" - Not sure how to set Race 2 with PTM off. Race 2 is a PTM mode.

mfain

I wonder if the throttle bar on the PDR is showing position of the throttle pedal, or if it is showing the throttle position sensor on the throttle bodies? In track mode with Race 1 or 2 selected, I am trying to correlate where I think I have the pedal and what the throttle is actually doing. Although it is not a technique I use, next time out I may trying going pedal to the floor off an apex and look to see what the throttle bar shows in the PDR replay from that point on. Something I noticed in the owner's manual is that the teen driver report card records number of TCS, ECS, and ABS activations - so the data is available somewhere in the "system".

Traction Control – the number of times
the Traction Control System activated to
reduce wheel spin or loss of traction.
. Stability Control – the number of events
which required the use of electronic
stability control.
. Antilock Braking System Active – The
number of Antilock Brake System
activations.

z28lt1

Traction Control, ABS, and Stability control are all available when looking at the PDR file in Pi Toolbox. I believe the Accelerator is pedal position, but will go play with some data to confirm.

Garret

Why do I get the feeling we are in for a "I just crashed my car" thread after this one.....LOL

RapidC84B

Some of us know what we're doing...

ChevyChad

I wonder is something like a soler performance throttle controller would help in a situation like this?

RapidC84B

Zero… those are snake oil.

Electron Mike

Nice! I dont have PDR on my car otherwise I would go hoon around and check for TC and ESC intervention in race 2 and everything off. Volunteers for the greater good?

mfain

Here is the reason I am trying to determine what interface I have with TC. On the second of three sessions on new slicks I had started to lap traffic on the 4th lap. Then, I had two unexpected instances of snap oversteer resulting in a spin with what appears to be no chance of recovery (instant counter-steer and throttle). The corners were short turn radius and fairly slow, but I was comfortably turning with a lot of lateral g - typical for this corner on slicks. Steering angle looked normal, and I was in Track/Race 1, so there could have been some TC intervention on corner exit. I was also consistently lifting the inside tires on this corner. I guess I need to get in Tool Box and see what I was doing with the throttle pedal, although I tend to be fairly consistent with no abrupt throttle inputs.

In this photo, everything felt normal and I had just started to pick up the throttle, but I did not plan on tracking all the way out so I could set up for a quick pass on the car ahead who was already giving me a point-by. That probably kept the lateral g loading a little higher and was the only issue I had with this corner in about 50 attempts in 2 days.



The snap oversteer occurred at this point with no warning and I attempted to correct within 1 second as I would with my other often tracked, no nanny, similar power cars, but to no avail. I think at that point the heavy rear end had me by the short hairs. There is a possibility there was oil on the track since another car had blown a motor in this corner on a previous session, but I didn't really see any evidence. I had some concern that I was at the traction limit on the outside rear tire when the inside tire lifted, but not sure. There is a possibility that there was a TC or e-diff event at that point, and hopefully I will be able to see that in a Tool Box analysis. If any of you credible track rats have thoughts, please chime in. These spins were relatively benign, but I am not anxious to repeat.

PRE-Z06

Is it possible the inside wheel being lifted off the ground and it’s speed changing enough relative to the others caused the computer to freak out? It’s impossible to program computers for every situation is my fear as we’ve seen with the issues of autonomous driving.

mfain

Maybe. I think z28lt1 had a good suggestion when he said a lot of the data could be found in a Toolbox analysis. I will investigate and see if the data shows anything weird during this incident. I don't mind a loose car, but I like a little warning of pending doom. The only thing that I have experienced that resembles this is when I adjust in too much rear brake and lock up the rears early.