amamoy2

Drivers Ed this week at VIR with Chin Motorsports. Running Pilot Sport Cups for the first time. 2006 997 C4. What pressures would you start at? Gonna be hot! Probably 90-95 deg. What pressure would I want when measuring right off the track?

Bob Rouleau

They like 32F 34R in 18 inch size, 34F 36R both hot pressure. Start six lbs below the target hot numbers cold. you will probably have to bleed some pressure when you come in.

amamoy2

They are 19 in. What what be a good starting point for them?

Thanks

Bob Rouleau

Six pounds below hot target as stated above.

mdrums

Are you a 1st timer at the track or have you been doing this for awhile?

If you are new to this just run the stock Porsche recomended tire pressures and work wth your instructor on pressure based on your driving. Also you alignment will play a big part in what pressure you will ultimately use.

I have been tracking a while and up to good speeds and my tire temp raise around 10-12lbs from cold to hot, especially during the hotter part of the day. When I 1st started out I was only getting around 6-8lbs of pressure rise but I drive a lot faster now thus the higher pressure raise.

amamoy2

Done a few DEs. Started with recommended stock pressures 36F 44R on regular Pilot Sports but was way too high coming off track. Picked up 8-10psi. Hence looking for guidance on reasonable starting pressures. I realize it is trial and error with many variables.

sws1

Absolutely, do not get the tire pressures above 36 PSI. Start out around 26 / 28, and watch your tire pressure monitor. Above 36, the cars gets very slippery. OR, start a bit higher (31 /33) and after each run, measure tires and let a bit of air out each time.

Yes - even if you are a newbie, you can watch your tire pressures. Why put yourself and others at risk but going with stock pressures and getting the temps way too high.

mdrums

I totally understand your thoughts on this and with most of my newbie students in the 2 second session if it is their 1st or 2nd track event I go over tire pressures with them. However I try to keep the front pressure up just a little to help save the newbie's tires from roll over and wearing out the outer edge since most likely they just have stock alignment.

MUSSBERGER

Don't forget the AWD. How will that effect things?

MJones

Michelin PSC targets Hot 32F 36R

Michelin Care and Feeding of PSC brochure CLICK HERE

Good reference material

Bob Rouleau

MJones - Note that the brochure you kindly linked to is for the "real Cup tires in 18 inches". The 19 inch N rated are more of a street tire and my experience has been hot pressures of 34F 36R is about right.

Note I suggested going out with 6 lbs less cold pressure. This will result in more than the target hot pressure if you are a fast driver. It is usually better to stop mid session and bleed off air than to go out with tires which are seriously under-inflated. After the first session residual heat in the tire assuming sessions are about once per hour will result in tire pressures which are about 6 lbs below target hot pressures.

Regards,

obsessedone

I tested MPSCs at various pressures from 38F/40R down in advanced DE at Watkins Glen and NJMP. Seat of the pants said best grip for my 997 S was at 34F/#36R. Had a chance to test with pyrometer at NJMP - which confirmed 34F/36R gave even temperatures.

So seems like for 997S 34F/36R as recommended by Bob Rochleau is good - I started 6-8 lbs lower cold, depending on ambient temperature - lower when colder.

RonCT

I've run 19" PSC N-spec on the track many times and in temperatures upwards of 98 degrees (those two hot days at Watkins Glen last year). PSI spiked upwards of 10.5 (passenger front) to 12 PSI (driver's rear) and target 34-36 hot. So, cold I start -11, -12, -10.5, -11 and after a few laps end up at 34, 36, 36, 34. I've never experienced an under-inflated issue as I ramp up for 3 laps anyway.

As Bob suggests, no problem being a little high and bleeding off. The above is with lots of experience and running in Black / Red, where being just a PSI or two high ruins the run (greasy).

amamoy2

VIR was awesome. Progressed to Solo on second day.

Started at 6-7 psi lower cold and wound up right at 34F 36R hot. Car really handled well.

EDH