[LESS1]

Originally Posted by BlueinTN

36 over your out of the ball park.

Not according to the hours upon hours of PDR data I have. All of my best laps occur when tire temps are 36/37 FR and 38/39 RR... on OEM GY tires. These best laps can occur at any point during a session without regard to ambient temperature. Obviously car laps slower in the middle of summer compared to winter. However, my best laps occur at the PSI stated earlier. YMMV, but I'm on my third set of pads and second set of tires with ~5.4k miles on the car. Have you reviewed your track data to confirm that above 36 PSI is slower or is this speculation?

[Badmojo]

Originally Posted by LESS1

Not according to the hours upon hours of PDR data I have. All of my best laps occur when tire temps are 36/37 FR and 38/39 RR... on OEM GY tires. These best laps can occur at any point during a session without regard to ambient temperature. Obviously car laps slower in the middle of summer compared to winter. However, my best laps occur at the PSI stated earlier. YMMV, but I'm on my third set of pads and second set of tires with ~5.4k miles on the car. Have you reviewed your track data to confirm that above 36 PSI is slower or is this speculation?

All my PDR data shows a significant drop in lap times at 36+ psig on GYSC3's. 37 is iffy, 38 is bad, 39 is go into the pits you are done. If you are only on your second set of tires, then your "hours on hours" is less than most of us track guys.

[Tim M]

In this case, I'd go with Chevy's instructions more than anyone on this board.

IMO few can really execute perfect laps that 2 psi is going to impact...I'm certainly not in that category...

I mean most tire pressure gauges aren't even that accurate from one model to the next...so we are all probably correct with what we are using to document, no? ;-)

[LESS1]

Originally Posted by Badmojo

All my PDR data shows a significant drop in lap times at 36+ psig on GYSC3's. 37 is iffy, 38 is bad, 39 is go into the pits you are done. If you are only on your second set of tires, then your "hours on hours" is less than most of us track guys.

And you're in a ZL1 so let's see you have the potential to carry more speed and work the tires harder than SS 1LE. Also not sure about your "less than" comment. This is not my first track only car. And I don't normally run TNIA/HPDE...etc with 4 - 6 20 mins sessions. Open track days for me whenever possible, with 3 or more hours on track time per day. By the way, I've owned the car in question for 7 months now not 3 years. And I did say YMMV right? Finally, I didn't realize this would turn into a measuring contest.

[relxn88]

I use a cheap temperature gun for reading the tires after a session on the track. I try to get the temps as equal, as I can, across the face of the tires (inside-center-outside). For example, if the center of the tire showed 20 degrees lower than the outside and inside, I’d add pressure and inversely, if the inside was 20 degrees more, I’d decrease pressure. The ideal would be to make the temps as close across the face, so the most amount of tread is on the track.
A radical example would be if you had say 20 lbs of pressure extra in a tire. The center of the tire would have more contact with the pavement than the rest of the tire. In effect - less grip on the inside and outside edges. We’re all trying to get the most grip we can.
I have found that one pound of air can make a surprising difference.