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Tadge answered:
Although we have talked publicly many times and published quite a bit of documentation about PTM (and other chassis controls), there continues to be additional questions. Assuming this section of the forum attracts a very tech-savvy audience, we are going to give a more technical description than our usual public statements. At the risk of helping our competitors, I have asked Alex Macdonald, our lead Corvette development engineer and expert in chassis controls to provide the definitive treatise on PTM. So, thanks for asking….

Performance Traction Management was first brought to the market on C6 with the 2010 ZR1 and was available on C6 Z06’s with MR from 2011-2013. It has evolved with each new model of Corvette since then but still retains the same functions and philosophy as when it was introduced. All of this discussion applies to any Corvette with PTM, not just the C7. For C7 any Z51 with MR dampers and all Z06’s are equipped with PTM.

The first important part of PTM is the traction control function. This is the core of PTM. Later I will describe the other adjustments it makes to the chassis but the fundamental change in each mode is the logic and calibration of the traction control.

It will help to understand how the standard TCS system works when not in PTM. See Fig 1 for an example of a C7 Z06 turning left at 25mph and approximately 0.8G lateral acceleration (a spirited left turn). The driver steps to 100% throttle (point #1) which causes the rear wheels to start spinning. Prior to spinning up the tires, the TCS system doesn’t know much about the road surface conditions. It could be wet, dry, gravel, coarse concrete, smooth asphalt, etc. To determine the surface condition the engine torque is allowed to increase until the wheels start slipping a certain amount (point #2). They would continue to slip at this torque level so torque is quickly reduced to stop the slipping (point #3). The initial engine torque that caused the wheels to slip along with how much torque needed to be removed to reduce the wheel spin are used by the TCS to calculate the type of surface the car is on. Once the surface grip is known the torque is added back in to maintain an amount of slip that’s appropriate for that surface (point #5).