I just ran a Road America last weekend. In my bridgestone potenza 760's I had 29 psi all
around. After a 20min session the psi went up to around 35. Buy the look of the wear I probally could have went down 1 or 2 psi in the fronts but the car was working so well I just left it.
I run 275/40-18 BFG KDWs all around and start at 32psi at all four corners. Depending on track, track temps, surface condition, etc. I adjust either up or down front or back depending on what the car is doing and what the tires look like. Maybe not nearly as scientific as using a tire pyrometer, but it seems to work well enough. After all I'm not in a competition, I'm out there to have fun and the car works well enough.
With the factory tires, I run about 38-40 up front and 30 out back for autocross. The rears still need some adjustment because I'm getting some roll over, but it's close.
This is with -2.5 deg camber on the front as well, so you're milage may vary .
Of course, best tire pressures are going to vary with the tire make, size, ect. Most of the Stang drivers I run with agree that 30psi is a good place to start. On my Kumho Exsta MX's I run 30psi front/ 32psi rear (cold). I come off the track in the 37/38psi range but that's after a cool down lap so.... The 32 rear isn't optimal either; it's an attempt to cut down on the understeer I get exiting the higher speed corners.
Take a piece of chalk with you and make some marks across the outside edges of your tires. Driving will wear off the chalk where the tire contacted the ground and that way you can see how much of the tire you're using. It's not perfect but it'll get you close.
So you're not letting a little air out to maintain a balance of warm to hot pressures? There is only a 25min break in between each session where we run. And with ambient always 85-95..it's easy to maintain a "warm" average.
I ran at about 30 when I did CMP 2 months ago. But I'm not technical enough to know what I need, except brakes. My instructor said I definitely needed more powerful brakes to handle my power.
I tried to tell him it's not that much power. (310 isn't that much)
I just picked up some DBA4000 rotors. Reviews were good and I am interested to see what kind of performance they will do pulling down from that high bank oval from 130mph over an over. They should work well with my existing brake mods.
I don't change pressures during the day to keep an average. I set them cold in the morning and then adjust them in two psi increments during the day as I go to keep the handling where I want it. It's futile to try to keep them even after that because they never have a chance to cool all the way.