Although this may seem like a simple question, it is almost impossible to answer in a simple way. The tire pressures you need depend not only on the car (weight/weight distribution/stiffness/shock characteristics), the tarmac characteristics (rough/smooth), features of the course (tight/open), the ambient temp (hot/cold), and the tire (age/type/size) but also on your driving style. IOW, one driver's ideal set-up may be completely wrong for you.
Really the only way to get an answer for you is for you to spend some time in your car on a skid pad with a tire pyrometer--and take a look at this:
'67 Lotus Elan S3 DHC (owned since 1970)
'06 Audi A3 3.2
'10 Lotus Evora