Sun- this is a question that should be asked of your local race tire vendor. There are far to many variables to be able to answer your question here.
Variables for psi include: bike weight, rider weight, riding style, talent and skill, track surface type, surface age, surface temp, tubes or no tubes, brand of tire, compound of tire, size of tire, age of tire and etc!
One way anyone can judge for themselves is to pick a good number based on an avg of riders with like talent, style and tire psi readings COLD. Then ride your ass off for about 20 minutes and check psi. A good start is around 2-3 psi higher than when you started cold. If psi is >4 add a psi for every psi over the 2-3 range. If it is <2 then air down a psi for every under. The reason- a tire will increase in psi in relation to tire temp raising. An underinflated tire will squirm more, causing friction between tire and tube and in the rubber of the tire itself. Friction equals heat which equals a corresponding rise in psi.
The reason I ask you to find a local race tire vendor is that he or she will know where you should start (if not exact numbers) which can decrease tire damage and wear (they ain't cheap) and possibly help keep you off the ground (possibly expensive AND painful). If nothing else- ask those at the track around you, use the same guage all the time and preferably a good one.