To find out if you really need more air, mark your tires with chalk or shoe polish. If you rub off the marks past the "safe" line, you need more air. Look at the marks on this tire and you'll see the pressures are absolutely dead on for the conditions of the track because the marks line up exactly with the rollover line (NHIS road course, November, 60 degrees, 38f/35r, Bridgestone RE730 215/45ZR17):
The fronts, however, had some rollover and should have been upped to around 40f:
And warm tires are gooey tires:
Of course, the pressures can be fine tuned further for desired performance handling but the rear marks show how to set pressures initially and then fine tune later.
There is no cone | PGT Impreza L Rally Car
| P Neon Rally Car
| What is a Trunkmonkey?