Porker tyre pressures

[beej]

posted on the porsche group but I guess more appropriate to this one..

following the 4th terminal clutch failure of the year in the caterham I am forced into taking the porsche round goodwood on Saurday (such a hardship I know!)

can someone please advise on ball park tyre pressures for a boggo standard 996 C4 running 17" P zeros. The PCGB says..

"Generally, Porsche tyre pressures do not need to be increased for track use. In fact for some models (later 911's in particular), you will need to lower the rear pressures, perhaps by 6-8lbs or more, depending how hard the car is being driven and how much heat is being generated within the tyres."

so that would be 32 to 34 on the rears? but they don't say hot or cold!

cheers

[GreigM]

Don't know about a 996, but I recently took the boxster with 18" wheels round the track with the standard pressures and it stood up well. I would suggest just to use the standard pressures at least the first time until you get used to it, and maybe then fiddle..but I'd reckon the pcgb guys wouldn't tell you to leave them as-is unless that was ok.

[oldtimer]

try 36 psi all round , after each session let some air out to get back to this while tyres are stll hot, after 3 sessions should have steadied out ie no more air release. NB rears need more let out than fronts as they run hotter , also both LHS tyres will run hotter if track is run clockwise ( mainly RH turns)