CobaltCr

Bet it's the valve stem. I check mine regularly. They loosen at a remarkable rate. I'm always impressed with how loose they can be before any air gets out. I guess with enough air pressure in the wheel it can hold the rubber gasket against the inside of the wheel and seal it.

I think huf valve stem caps should be tightened to 35 in-lb of torque.

mqandil

+1 I completely agree. this is where I am placing my bet. 3 of my cars were leaking air from there. Check if the nut is loose and retighten the nut back between (4 to 6 N.m or 3 to 5 ft.lb). Mark

bigkraig

Yolo!

longboarder

Big thanks to GMG today. The inside of the rear driver side tire had a screw in it which i somehow missed. They did not have the tires in stock but they found a new pair of rears locally and picked them up for me and had me on my way in no time.

While I was there picked up these carbon fiber inserts which prevent that nasty wind buffeting on a track day. I tracked my 991 Turbo S a few weeks back and the buffeting over 130 was really annoying.

Thanks GMG!

Cheers.

kfmcmahon

would anyone have kept that tire with screw in it for street driving?
could it be plugged? (not for the track obviously!!)

aamersa

Yeah sure. I had a similar screw causing very slow loss of pressure in my rear tire on gt3 and kept it for a while for street use. Eventually I had it plugged for $15 at a tire shop which eliminated the pressure loss and is getting me through Summer. I didn't track with this tire. Now my fronts are so worn that their surface looks like slicks. No tread remains. So I need a new set of four tires.

longboarder

Tires are yours if you want them! You in SoCal? Just need to pick up at GMG.

kfmcmahon

LOL, not quite SoCal..

gmgracing

Hey, we're glad to help. Errant screws are pretty frustrating.

-Andrew

trader247

Curious if you got to ACS on Saturday. What were you thoughts of the car in those temps?

hughp3

my car did same thing. the valves stems must be torqued to xx INCH pounds but i do not recall. I could literally unscrew 2 of them by hand.

Edit: saw it was a screw....

longboarder

I did Sunday which was hot and humid. It was over 100 degrees by the second session. But the last session at 3pm it was ridiculous. The tight corners were impossible. The car pushed really badly it just wouldn't turn it was so slippery. But I was out with maybe 6-7 other cars so I didn't care just worked on form the best that I could without worrying about other cars. Earlier sessions were crowded. This is my third time at ACS in triple digit conditions so I already had an expectation of what the track would be like.


GT3 was amazing. Oil temps didn't budge so I know it can be pushed much harder. It's pretty clear the stock Cup2's don't like that kind of heat. I'll try different tires at some point. Despite the heat I was with a bunch of friends and we had a blast.


The one thing I didn't like is that the track moved the small corrugated metal barrier for turn 3 requiring to make the turn deeper and as a consequence it was difficult to set up for turn 4.

trader247

Thanks for the info. The sport cups are really good for a street/track tire, but will give up in that much heat.

When it is this hot, the early sessions are much better for a multitude of reasons, but then it can be too crowded

I was gonna go, but my crew was testing and I could't make it as they had to work on my car. I will be there for POC event in September. Stop by and say hi if you make it out.

aamersa

100 degrees is not that bad. Most of my track days in Dubai are above that temperature.

You need to deflate tire pressures so they are not more than 30 psi when fully hot to maintain best tire grip.

longboarder

Yes would appreciate meeting up and learning some tips. Do you have a pic of your car so I know who to look for?


You were spot on about the crowd. And inverse relationship between the temps and number of cars on the track. I never got a clean lap until the 3:10pm session and by that time it was 105 degrees and being sunny who knows how hot the track surface was but it instantly made my tires greasy so I had to battle my tires during the entire session. But was able to turn my best lap times - did four 1:49's with a best of 1:49.1. Not that great for a stock GT3 but the aftermarket alignment was poor (showed the specs to GMG) and of course the greasy tires made turns 4 and 9 impossible as the car just pushed wouldn't turn. So a starting point for hopefully some nice improvement. Goal is mid 1:40's for a totally stock GT3 with just alignment.


If you track in the Dubai summer you have my respect. I hear it's 50c/120f every day. With those temps you would have to change tires. I'm guessing Cup2's would be dangerous after a lap or two.