I know you can enter PTM from the track setting, but what happens if you don’t select a PTM mode? What will the driving experience be like in track mode alone? What PTM setting does it emulate?

 

When you enter PTM you are in Performance Traction - Wet by default.

 

but what if I don’t select any PTM mode. I have my Z mode set to emulate track settings, so it’s not in any particular PTM mode.

 

The same question came up on C7, and I never saw a definitive answer. The only time I go to Track mode in my C7, I double click to enter PTM.

With C7 you had to have MSRC to have PTM. Is the same true on C8? If so, it's probably similar to the default Track mode on non-MSRC C7s, whatever that is.

 

It seems to be the same. PTM requires FE4...

 

According to the following chart, PTM is not available in Z-Mode:

 

What we need for C8 is the comparable chart for Track PTM in C7.

 

Here is what happens with a C7 that is being operated in one of it's 5 Track/PTM modes when the center button is pushed (for example if the selected mode is RACE). When the selector is in one of the 5 PTM Track Modes press and release the center button to turn off PTM and return to the traction control and StabiliTrak/ESC systems. The traction off light and StabiliTrak/ESC OFF light will go out.

Basically, all you have is a stiffer suspension and stiffer steering but the nannies are on and there is no PTM.

The C8 OM should have a similar description. I have the impression the C8 OM is like the C7 OM and drivers will have to memorize the driving parts of the OM to be able to make full use of the car's potential.

Bill

 

I know PTM is not available in Z mode, but if I was in track mode and don’t select a PTM mode, what does that correspond to on PTM mode?

 

It's disappointing that you can't directly link a PTM mode in Z-Mode and even more so that it isn't even available in Z-Mode. The Performance Reference Guide lists it as available so I guess that is a mistake.
I wonder why they did it this way. Is it an oversight? It doesn't seem that technically challenging to be allow it to be directly linked. Or perhaps the lawyers didn't like it. They probably don't like that a Track mode even exists.

 

It appears what you have is all Track settings without PTM on. PTM overrides certain Track settings when engaged. For example, you have MSRC Tour mode in Track PTM-Wet in C7.

Without the comparable C8 PTM chart, we don't know exactly how it's set up.

 

I guess its a liabiltiy thing. One good program the Z mode to have the nanies off, and another driver may inadvertantly hit the button.

 

Good point. While most PTM modes have varying levels of TC and DSC still on, Track PTM-Race has DSC off and TC in a minimal intervention mode. From a liability standpoint, it's good to force the driver to go through multiple steps to do that knowingly and purposefully. Having it on a single button, could be a source of liability.

Even in regular Track mode, to get to PTM Race it takes 2 button presses and 4 turns of the dial on a C7.

 

I can only comment on the C7, not the C8, but I have a Z51 with MRSC, and have used PTM on the track on many occasions.... here's my personal experience, simply as a driver, not a SME on GM's engineering software....

- First, just putting it in Track mode, the Traction Management ("TM"), is too invasive, and the car is undrivable on the track.

- Setting the PTM to "Race" removes the TM, but, depending on your tires, and the track conditions, the car is difficult to control on corner exit, as the torque can break the rear tires lose very quickly.... the MPSS tires, are very temp-sensitive and unpredictable.... its a "spin in s box".

- Setting the PTM to "Race" mode does not disable the yaw control, and going around the "lightbulb" turn at NJMP, and powering on as I usually do, the left-rear brake burned through a brand-new set of track pads, and scored the rotor in 20 minutes....... I asked this question 100 times on this site and nobody can explain the relationship between PTM "Race" mode, and Yaw but a scored rotor answered the question... it still activates, and you don't want that on the track.

- Now, with a set of MPSC2, I set the car to PTM in Sport 2, and that is a good compromise.... the back end can still kick out, but it keeps the car under reasonable control. So that's the best setting I can suggest unless you do a full race setup with race tires.

 

My experience with my C7, other than PTM Wet, you shouldnt use PTM off track or autocross.

 

I generally agree, but PTM Dry is also a safe setting on dry streets.

 

OP you'll never be driving hard enough on the streets to see any benefit from PTM. It's racecar tech for the track. Just setup your Z mode and enjoy it. Should you decide to start doing trackdays you can explore the various PTM sub-modes.

I would assume that putting the car in track mode and not entering PTM the car will default to the most conservative setting? It'd be a good question Ask Tadge.

My plan is to setup MyMode for my preferred commute, Z mode for fun curvy roads, and then when I'm on track I'll use track mode PTM Race.

 

I do disagree a bit. For example, PTM-Wet is a very good and useful setting on the street. It provides max power for that condition without any loss of traction. It actually works better in the wet than regular Tour mode on the C7.

Sure there is Weather mode too, but that just makes the car feel dead.

 

OT. Good news guys. On my 2021 C8 that is equipped with Z51 and MRC, I am able to customize PTM options in Z-Mode. In Z-Mode, the PTM options available are: Inactive, Wet, Dry, Sport, Race 1 and Race 2.
Note: If PTM is set to anything other than Wet in Z-Mode, the Suspension automatically is set to Track/all the way to the right. If you try to change suspension to Sport/midpoint PTM is disabled in Z-Mode.

• The 2021 Owners manual: Wet, Dry, Sport 1, Sport 2 and Race.
• The 2022 Owners manual: Off, Wet, Dry, Sport, Race 1 and Race 2.

Once PTM is set to Sport in Z-Mode, after a vehicle restart, the following warning is displayed.




This must be a warning required by the lawyers as PTM does stay in Sport/as configured previously after a vehicle restart.






Robert MacCready posted this great video back in June on this topic: To state the obvious, Race 1 or Race 2 should only be used on a closed course.