My car has run a 1.57 on the M/T's. I decided to start out at 21 psi and it would consistanly cut 1.5's there so I left it. I plan to do some experimenting to see if lowering makes any difference. My theory is I want to run the most pressure I can and still hook so that the tires have less rolling resistance once going down the track. I am sure you have pushed a car with a half flat tire and its a lot easier with more air!
