Egoncool

Have not and am reluctant especially in a new car. I do think it is the traction control but it shouldn’t be that intrusive. It is occurring at the top of second gear at 65-68 mph. Wheel is being unwound and throttle gradually applied. It’s not like I’m mashing it. Seems like it totally cuts power instead of slightly cutting back, but the car is totally stable. It’s not sliding. There is no need for such massive intrusion. I have 60 days at VIR. Probably over 2000 laps going through turn 1 and never experienced this in my C8 Stingray or Porsche Boxster.

Racingswh

Every single lap at the same spots on track every time regardless of pace?

Does sound like something is off with the TC calibration to be honest. I would be trying it in different modes. With that many laps there I would not be overly concerned about switching to Race 1. I would just want to see if the problem is comparable in all modes. In areas of the track where you are more concerned about being in Race 1 I would just be more gentle with throttle application. I assume you are there again tomorrow? Are there any others there you can ride along in? Do you have the factory wheels you can put back on the car to see if it happens?

Does anyone here that has one and has been to VIR have any input? As you mentioned replication by the dealer will be a PITA.

spearfish25

Just put it in Race 1 for that turn and then go back to Sport. Seems like you’d know if that was the issue in a single lap with only one turn in Race 1.

C8gofast

I have a track only C8 Z06 and had the same problem in PTM Sport . It improves in Race 1, but the nannies still intervene. I run Race 2 and it makes a huge difference in the performance of the car.

Vrrooom

I ran into the same thing in my Z51. It was intervening too much unless in Race 2. Which yielded times much faster as well and did a great job with throttle rotation. Have not had a chance to take the Z06 on track.

MitchAlsup

Just to be sure, when I said apex earlier, I used the wrong term, I was using apex as the point of minimum speed and maximum lateral acceleration, then you start to add throttle and wisk by the actual apex (closest to the inside of the road) while laying on power.

You are also right about momentum cars taking a more classical line while higher HP cars want to lengthen the straight more than minimizing the cornering.

range96

I didn't see an answer to my question from OP.

With softer compound tires the computer intervention will be more evident. With the current info, I would not rule out that scenario. The non-Z07 system is calibrated with street tires and the effect of a change in the ratio will be amplified with stickier tires.

AzDave47 commented the ratio is more commonly calculated in reverse order, i.e. 27.8/26.5 ~ 1.05 and gave a range of 1.03 - 1.07 as acceptable (instead of 26.5/27.8 ~ 0.9532). We are talking about +- 1.9% variation.

As pointed out by many, running in race 2 will answer if the computer intervention is the culprit (I suspect) or something else.

Electron Mike

I had the same problem in 2nd gear corner exits on track using PTM sport, very annoying and it unsettles the car. Moving to PTM race 2 eliminated the issue for me. You could also try competitive driving mode which still has stability control active with TC off to prove its the traction control in your situation. Competitive driving mode is only available in sport drive selector mode though with cars that have PTM, so the dampers will be set softer than race drive selector mode.

Egoncool

I looked at some data and can’t find a problem. The rpm and speed traces are linear, but there is an intermittent seat of the pants stumble.
the other interesting thing is a round green light on the dash during track sessions. This is some sort of competitive driving mode that makes the tranny more aggressive. I never saw this in the stingray. I thought competitive mode was a non ptm mode, but I was in track ptm sport. Is this something new?

AzDave47

Page 89 of the 2023 OM:
Performance Transmission Active
This light turns green when:
. The vehicle is being driven in a spirited
manner and transmission shift points
have been altered to enhance the vehicle
behavior. See “Transmission Shift
Operation” under Driver Mode Control
0 208.
‐ For track driving events that require
standing starts, Performance
Transmission behavior can be activated
near a standstill by selecting Track
Mode > Performance Traction
Management (PTM) > Race 1 or Race 2.
You can also engage PTM using Z
mode, if PTM has been configured to
Race 1 or Race 2. See “Performance
Traction Management (PTM)” under
Driver Mode Control 0 208.

Electron Mike

I can see the sudden drop in acceleration in my track data, example below where acceleration G's dip and then climb back up during 2nd gear track out.

RapidC84B

Need data to give you an actual answer, or a PDR video, but most likely you're experiencing PTM. It cuts power and the engine makes a "brrrrrrrrr" fluttering noise (at least in the LT2). I haven't tracked my Z06 yet. VIR is my home track.

If I were betting, I'm guessing PTM sport is engaging traction control/PTM.

Mitchell_B

Why don't you shut the traction control off and see if the problem goes away?