Boxster track tire pressure

[Michael 10256]

I have a 2006 Boxster base that I track. It has 18" Michelin Pilot Sport 4 S tires. The owner's manual recommends 29 lbs front and 36 rear. For track use, how much should I inflate the tires cold?

[djnolan]

The tires can be inflated up to their max rating and will be more stable and efficient near their highest inflation. The owners manual recommendation is for comfort.

[tonythetarga]

Let's put a bit more context to the question...
Track tire pressures are going to change depending on a lot of different factors. Starting tire pressures should be based on what type of weather you have, ambient temps and driver experience on track. Tire pressures will 'grow' as you drive and create friction. How much it grows depends on starting pressures, ambient temperature and driver experience.
The best starting advice is start at the recommended tire pressures and check tire pressures immediately after four or five laps. Leave a tire gauge at the pit wall and stop and check in a safe position. Option is if you're an instructed driver, start with pressures a few lbs less than manufacturer's spec and check after your run.
I use Michelin 4S as well and optimal hot temps for me were 33-34 front and 38 rear. Higher than that and corners can get slippery from overinflated tires.
There is no 'one' setting and forget it. Tire pressures change all the time. You need to make your best determination in the morning based on ambient temperature and actual cold pressures. Then adjust as necessary during the day.

[CarGuyNeil]

Or set to stock pressures. Just remember if you are checking pressures and the tires have been driven on they are now hot and the tire pressure setting is for cold tires so go 3lbs over that for hot tires. Then bring some white shoe polish and mark the tires in either 3 or 4 places around the tires on the shoulders. If after those 3 or 4 laps the white marks are gone, you need to use higher pressures. The opposite applies if there is no wear on those marks.

Sent from my SM-S938U using Tapatalk

[mikefocke]

Any of you ever used a temperature sensing/displaying gun to set up your tires? Multiple spots to see where the friction occurred.

[CarGuyNeil]

Originally Posted by mikefocke

Any of you ever used a temperature sensing/displaying gun to set up your tires? Multiple spots to see where the friction occurred.

Rich guy equipment. I grew up on the shoe polish method. Lol


Sent from my SM-S938U using Tapatalk

[mikefocke]

Actually cheap ($10 to $50) and useful around the house for checking the air vents.

[dad911]

Originally Posted by mikefocke

Any of you ever used a temperature sensing/displaying gun to set up your tires? Multiple spots to see where the friction occurred.

I always did, as did the guys I raced with.

The IR cameras have dropped so much I’d probably try that if I was still racing.

[stealthn]

Street tires or slicks?

[Cajundaddy]

Originally Posted by mikefocke

Any of you ever used a temperature sensing/displaying gun to set up your tires? Multiple spots to see where the friction occurred.

Yes I do. Once the setup is right I don't spend much time with zone temps but I am more interested in comparing hot temps to lap data. Different tires have a different sweet spot in terms of heat and I like to keep them in the zone for Time Trials and AX.

To answer the OP I typically air to around 29psi in the first session AM and then air down as needed to get 32-34psi hot. At this pressure and on current tires around 110F I am getting my best grip data and lap times. I keep a log of this and as tire choices change, I log them as well.

For reference
120 track days in a 1998 Boxster
80 tack days in the current 2009 Cayman

[stealthn]

Bot