matt33

Expecting rain this weekend and running PS4S for the first time on a 997 GT3. What hot pressures do you target? (I like to run NT01 33 hot all round)

Thanks
Matty

Hella-Buggin'

T-Hill? I haven't run the 4S's but have run Pilot Super sports there many times. After 38psi they start getting greasy. The issue is the sidewalls aren't very stiff, same as the 4S I believe
and airing them down enough to keep in the range makes the first few laps feel like you're rolling on giant gum *****. I'd usually drop down to about 24/28 cold after a few sessions.

matt33

Hella-Buggin'

I'll be there. Look out for me.
PM sent with details.

JTT

Sorry to hijack the thread, but curious Mark, at 24/28 cold, what are you seeing for hot pressures? When you say "after 38 psi they start getting greasy", do you mean hot pressures in excess of 38 psi? I'm trying to sort pressures for PSS myself. Any guidance appreciated.

Hella-Buggin'

I was able to keep pressures close to 38 Hot on the rears with that. Maybe start a little higher and bleed down as needed after a session. Just be careful, the first few laps are needed just to get more pressure built up.

Steve113

Rain start about 5-8 lbs higher then dry. Worry less about pressures and more about smooth inputs and rain line. I always go by shinny is bad dull looking surface is good

Hella-Buggin'

Yes, Avoid the painted curbs. Have fun. A wet track can be a blessing for learning what not to do as your mistakes are made very clear.

JTT

Thanks Mark!

matt33

JTT

Interesting. Recommends mid 30s and/or hot pressures similar to recommended pressures for street, however what about when recommended pressures are mid 40s like some of our cars (44 psi recommended rear on my 996)....that's a big spread.

matt33

In the wet: I found 36ish hot to work pretty well. It was extremely wet (rooster tails) and the 4S was very impressive, especially the straight line stopping.

In the dry: I liked them a softer at 33ish hot. Found them a LOT slower than track-first tires (some of that likely to be familiarity/confidence/etc) , but great fun once I found pressure that worked for me. Quite communicative and no surprises.. just cant compare lap times vs good dry tires.

Matty

Difool

Like many tires the best performance will be in the low 30s! But like people here have said the sidewall on those tires is soft, and at 32 you will burn through the outside edge unless you are running some serious negative camber. When I ran MPSS I found 36-37 was my hot target, and I could always tell when I hit 39.

unless you are running something extraordinarily light or heavy, the track temps will be pretty consistent across cars, unlike the car’s street specs. Hoosier recommends higher pressures based on weight, but many believe that’s mostly to cover their *****. I read an article where he Yokohama race rep gave the track pressures for the AD08R and said they were the same iregardless of wheel size and car.

Sometimes the street pressure recommendations are bonkers. 2010 Cayman S with 19” wheels has over 40PSI for the rears, per the door plate. That obv won’t translate well for the track!

minthral

4S seem to like mid 30 and anything near or over 40 doesn’t handle well. Problem is the rears need 5-10 more than front and if you go lower than 30 on front there’s sloppiness. Basically you want get front as low possible without too much slop then +5 the rear. 32/36 works okay for streets... when hot it will be 34/38. For more agressive driving or track you probably want 28/32, but it’s going to be sloppy until warm up (33/37$. Honestly not the best track tire.