Ray G

To tell you the truth, I don't think I've ever really analysed my "percentage of speed" when warming up. It's just something I do. I do keep my top speed down quite a bit the first couple of laps, because it requires braking hard and cornering at the end. Btw, I also go easy on the brakes too at first. Also, my 100% is much less than the 100% limit of the CGT!

redpackage

Just finished two DE days at Watkins Glen. Started the day with tires once again at 32 psi cold all around, and after each 20 minute session, the psi rose to 42-43 on the left and 40-41 on the right. Track is run clockwise. Air temp was in the 75 dg range on day 1 with some sun and 60 dg range on day 2 with clouds and then light rain. On day 1, the tires got "squishy" during one hard run (when the track temp was hottest and the sun strongest), but all of the other runs felt normal. These were the 3rd and 4th track days on these tires. Pocono is next month.

thusly

Approximately how many track days are people getting out of the MPS2s? Under hard, moderate or conservative driving styles?

redpackage

I was told by Michelin that the tires are good for about 50 temperature cycles. With 4 run sessions per track day on average, I anticipate 10 track days per set of tires. This assumes one doesn't drive on the street in such a way that the tires cycle to the maximum heat and psi that they do on the track.

redpackage

Has anyone upgraded their tires from the MPS2's for track use? I just finished a session at Lime Rock and felt that even after lowering the starting psi sufficient to keep the hot psi in the 36-37 range, the CGT could use more grip in the corners. Others with MPSC's seem to be cornering better.

redpackage

Just finished a two day track event at Roebling Road. Total of 7 hours of track time at speed. My earlier comments from 2005 were off the mark as the OEM tires are MPS2's NOT Cup tires. Beginning the day at 32 psi, cold the tires went up to as much as 43 psi on the LF and 30 psi on the RR. Dropped the starting psi's down to where the hot tires maxed evenly to the 37-39 psi range and that was about as much grip as I could find.

Next year I'm moving to slicks as the guys at Manthey convinced me that the difference will be night and day. I spoke to the tester who logged some 200-300 KM on their new set up and he claims the CGT finally feels like a race car. We'll see.

Jarez Mifkin

Once you go slicks, you'll never go back...

redpackage

I sought advice on tire pressures since I am switching to Pirelli Corsas for this spring. According to Schlag, who tested the Corsas versus the Michelin PS2's at Spa, there was a 4.2 second advantage with the stickier tires over the OEM's on this 5.7 km circuit (i.e. almost 1 sec per km.). As to pressures, he recommended hot psi ending up close to recommended street cold psi on the Corsas. Therefore, one should start with 0.4-0.6 bar less at the track (I think this is about 7 psi lower). The MPS2's were optimizxed at 36 psi hot and they started with 26-28 psi cold. Schlag claims street tires optimize the contact patch at the recommended cold psi and it shrinks with more too much psi and the suspension gets firmer (effective spring rate increases). This corresponds to my experience i.e. as the hot psi of the MPS2s dropped from 42-40 and then 38 my tires performed better last year. I will try 36 next time with these tires.

RS Clubsport

redpackage, I've just got my tires from Guenter Schlag. Have you ordered the BBS race wheels from Hr. Armbruster?

This is very interesting the improvement on circuit times, he said the difference was significant.

redpackage

RS Clubsport: BBS wheels and Pirelli tires have arrived and the car should be on track mid Feb at Homestead. I think the shop sourced wheels and tires in the US. I don't collect lap times. For comparison, I'll be running with others that I know. Schlag claims that we should get 80-90% of the benefit of slicks remaining street legal and says tires are optimized for a 4 hour enduro race or 600-700 KM on track under race conditions. Since I anticipate 6-7 hours of track time for this 2 day weekend, it should pretty much use up a set. Last year at Homestead, with OEM wheels I couldn't stay with the 430 Challenge cars on their race tires in the turns but was faster on the straights. We'll see what happens this year.

Steve N.

It's too bad that the MPSC's were not provided from the factory on the CGT. Wonder why the GT3 got them - but not the CGT?

RS Clubsport

And these are the Pirelli Corsa 255/40 x 19 front and 355/35 x 19 rear (I presume they are as this is what mine are.)

redpackage

RS Clubsport: We ordered PZero Corsa System tires from Tire Rack. Link is: http://www.tirerack.com/tires/Sizes....o+Corsa+System.
Sizes are front: 285/35ZR19 and rear: 345/35ZR19. We expect to need steering rack stops due to front tire width. Circumference is within 2% of the OEM Michelin PS2s. As to inflation I'm going to start at 28psi and try to get the hot psi to mid 30's for a benchmark. Hope this helps.

redpackage

RS Clubsport: The 285 width tires didn't fit the front wheel arch so the shop mounted 255/40x19 front and 345/35x19 in the rear. They took the front screens off due to interference. Schlag recommended 32-36 psi hot so I am starting with 26-28 psi cold and we'll see how they perform. Let me know how it goes. I will be at the track this weekend.

RS Clubsport

Guenter said the 285 would'nt fit, I asked for this same option. I've got the same set up as you 255 front and 345 rear, my tyres are here and the wheels will be arriving from BBS this week, I'm trying to get them on for a track day this Saturday.

Guenter said they were worth 4.5 seconds round Spa so I expect they will be impressive!

On my MP Sport I've started off around 28-29 cold and got to 35 hot so I suspect you may need to bleed more air out with the stickier Corsas. When you mean the front screens, do you mean the splash guard in the wheel arch?