997 PS2's after a track day...
10-02-2006, 12:47 AM
#31
Originally Posted by cgomez
From my own experience, anything less than -2.5 of neg camber up front will continue to cuase outside shoulder wear if you drive the car at the limit at the track.
To run that type of camber or more (I run -3.5) you need to replace the lower front control arms with GT3 Cup Car parts.
If you track the car enough is a cheap solution to extending tire life. Otehrwise tracking your car will become very expensive if you drive it hard. With the OEM camber, the car is still fun, and you can make it turn by loading the front under braking, but it just rides on the shoulders too much under steady state cornering. It's just the nature of the mcpherson strut setup.
To run that type of camber or more (I run -3.5) you need to replace the lower front control arms with GT3 Cup Car parts.
If you track the car enough is a cheap solution to extending tire life. Otehrwise tracking your car will become very expensive if you drive it hard. With the OEM camber, the car is still fun, and you can make it turn by loading the front under braking, but it just rides on the shoulders too much under steady state cornering. It's just the nature of the mcpherson strut setup.
I don't agree that you can apply your camber recommendations in this case. Nearly all Porsche race cars running that amount of negative camber are on 18" wheels with higher profile slick tires that have more grip and experience more sidewall flex. You can get away with less negative camber on 19" wheels and street tires if you keep the pressures up. Running -3.5 degrees camber on 19" street tires on a street car is a recipe for trouble. The inner half of the tire would take about 80% of the vehicle weight and the same amount of wear. The tires would be toast in 5k miles.
Either way, if this car is used primarily for street driving, don't go with more than about -1.5 up front and -1.8 in back or you'll enjoy a few degrees better performance on the track but give up a bunch of durability on the street.
MC
10-02-2006, 12:53 AM
#32
Originally Posted by RonCT
Listen to Frayed, he knows his stuff. Those tires look perfectly normal to me after a nice day at the track. After a few weeks of street driving you won't tell they were on the track. The Melt goes away leaving behind normal compound. If anything, pressure is the concern - you want to operate PS2s at 40-41 hot maximum - I usually start at about 35 cold all around and adjust after the first session - every track is different, so try one pressure and bleed (shouldn't have to add).
Don't get hung up on camber. As has been stated, PS2s are near R-compound - they are what I used on One Lap (as did about 90% of the field in 2005). They are fantastic tires. If you take this so far to use lightweight wheels, PSCs, modified suspension, etc. - then you can worry about camber.
How are your pads and rotors? If they are OK, then you really don't have a worry about tires. Once those go and you switch to Orange, black, or gray, then you probably will need more in the tire department.
My guess is eventually you'll get into a routine of jacking up the car, pulling the oem wheel / tire, swapping pads, and putting on a lightweight wheel with PSCs on. Very formidable!
I run my PS2s (rain / cold days) 35 cold and adjust down to 40-41 hot. My PSCs are 28 cold and 34-35 hot. You can probably find this in the "tire care" section at Tire Rack where the PS2 and PSC is described. Some of my track buddies talk about different pressures, so my experience is based to date on my M3...
Don't get hung up on camber. As has been stated, PS2s are near R-compound - they are what I used on One Lap (as did about 90% of the field in 2005). They are fantastic tires. If you take this so far to use lightweight wheels, PSCs, modified suspension, etc. - then you can worry about camber.
How are your pads and rotors? If they are OK, then you really don't have a worry about tires. Once those go and you switch to Orange, black, or gray, then you probably will need more in the tire department.
My guess is eventually you'll get into a routine of jacking up the car, pulling the oem wheel / tire, swapping pads, and putting on a lightweight wheel with PSCs on. Very formidable!
I run my PS2s (rain / cold days) 35 cold and adjust down to 40-41 hot. My PSCs are 28 cold and 34-35 hot. You can probably find this in the "tire care" section at Tire Rack where the PS2 and PSC is described. Some of my track buddies talk about different pressures, so my experience is based to date on my M3...
MC
10-28-2006, 11:36 PM
#34
Poseur
Rennlist Member
Rennlist Member
Congratulations. It looks like they are performing exactly as they are supposed to. It also looks like you have the pressures dead on. Would love to know what your tire temps are after each lap. Could you share that sometime? I'd be curious to know (for all four) the inside tread temp, center, and outside temp. A pyrometer or a surface temp gauge would be fine.
11-05-2006, 05:53 PM
#38
I'm confused, and it's important to me because that is exactly what my PS2's looked like after my last track day this year.
What does "corded" mean?
There seem to be conflicting posts regarding thr tire pics: one seems to say they're fine, another says they're "corded" (which doesn't sound good to me).
So what's the deal?
-B
What does "corded" mean?
There seem to be conflicting posts regarding thr tire pics: one seems to say they're fine, another says they're "corded" (which doesn't sound good to me).
So what's the deal?
-B
11-05-2006, 05:55 PM
#39
By the way - I completely agree with the post about making sure the car has completely rotated before accelerating, but I would add that it's very important to squeeze the throttle after a turn rather than mash on the gas. That will also help prevent the understeer that is such a common beginner's mistake, and also leads to incredible wear on the fronts.
-B
-B
11-05-2006, 06:03 PM
#40
Race Director
Originally Posted by Bullet
What does "corded" mean?
-B
-B
There was decent tread left (above the wear bars) but the tire (only 1) is junk. If I continued that day the rest would have wore down to the cords as well.
