GT3 Mk.1 Post Track Day
Discussion
Hi, I've just tracked the GT3 for the first time on Saturday at Sepang (Malaysia).
Had a good look at the car just now, and it seems that the front discs are now discoloured over the swept area of the discs, and the rear tyres (Pilot Sport Cups) have bits of chunky melted(?) rubber filling up some of the thread. The fronts seem fine, if a little rougher in texture (ditto for the rears) than before the track day.
Does this mean that the front discs need replacing? What is the legal thread depth of PS Cups (if there is such a thing)? How do I know when they need replacing?
I also suffered pretty sudden and extreme brake fade on my 10th or so "hot" lap. Is this normal for a Mk.1 (it was pretty hot that day; 33-35 degrees air temp)? My mates are taking the piss, saying that it was improper braking technique that caused the fade; I try to brake hard but progressively, heel and toe'ing, before entering corners, they say I should be "jabbing" the brakes harder (ie. non progressive) and letting go almost immediately?
All in all, the car was absolutely fantastic on track, several leagues better than the e46 M3 I used to own, and if it's possible to fall in love with a car, I think I have done so! If only she wore her tyres better (they do seem very much the worse for wear), and her brakes were up to my "improper" braking technique.
Lastly, I ran hot tyre pressures of 34PSI and 36PSI, front and rear respectively, does that seem right for PS Cups on track?
Thank you.
Had a good look at the car just now, and it seems that the front discs are now discoloured over the swept area of the discs, and the rear tyres (Pilot Sport Cups) have bits of chunky melted(?) rubber filling up some of the thread. The fronts seem fine, if a little rougher in texture (ditto for the rears) than before the track day.
Does this mean that the front discs need replacing? What is the legal thread depth of PS Cups (if there is such a thing)? How do I know when they need replacing?
I also suffered pretty sudden and extreme brake fade on my 10th or so "hot" lap. Is this normal for a Mk.1 (it was pretty hot that day; 33-35 degrees air temp)? My mates are taking the piss, saying that it was improper braking technique that caused the fade; I try to brake hard but progressively, heel and toe'ing, before entering corners, they say I should be "jabbing" the brakes harder (ie. non progressive) and letting go almost immediately?
All in all, the car was absolutely fantastic on track, several leagues better than the e46 M3 I used to own, and if it's possible to fall in love with a car, I think I have done so! If only she wore her tyres better (they do seem very much the worse for wear), and her brakes were up to my "improper" braking technique.
Lastly, I ran hot tyre pressures of 34PSI and 36PSI, front and rear respectively, does that seem right for PS Cups on track?
Thank you.
The Necessary said:
Hi, I've just tracked the GT3 for the first time on Saturday at Sepang (Malaysia).
Had a good look at the car just now, and it seems that the front discs are now discoloured over the swept area of the discs, and the rear tyres (Pilot Sport Cups) have bits of chunky melted(?) rubber filling up some of the thread. The fronts seem fine, if a little rougher in texture (ditto for the rears) than before the track day.
Does this mean that the front discs need replacing? What is the legal thread depth of PS Cups (if there is such a thing)? How do I know when they need replacing?
I also suffered pretty sudden and extreme brake fade on my 10th or so "hot" lap. Is this normal for a Mk.1 (it was pretty hot that day; 33-35 degrees air temp)? My mates are taking the piss, saying that it was improper braking technique that caused the fade; I try to brake hard but progressively, heel and toe'ing, before entering corners, they say I should be "jabbing" the brakes harder (ie. non progressive) and letting go almost immediately?
All in all, the car was absolutely fantastic on track, several leagues better than the e46 M3 I used to own, and if it's possible to fall in love with a car, I think I have done so! If only she wore her tyres better (they do seem very much the worse for wear), and her brakes were up to my "improper" braking technique.
Lastly, I ran hot tyre pressures of 34PSI and 36PSI, front and rear respectively, does that seem right for PS Cups on track?
Thank you.
Ok, one at a time
firstly the easy one - tyre pressures, they sound too high. In the uk we run around 2.1 bar (31 psi) hot all round and it makes a big difference.
As for the brakes, the discolouration will be due to the temperature. Its not a problem as long as you don't have lots of cracks between the holes on the discs. Most MKI owners in the UK manage to crack their front OEM discs after one or two days on track. The only long term solution is to upgrade the discs to solid / floating disc set up. In the UK PARR or JZ MACHTECH would be able to supply the kit but on your car it would also require a caliper upgrade from 4 pot to 6 pot (as the discs are bigger)
This brings me on to the point about brake fade. To a certain degree your mates have a point however the four pot setup on the GT3 is much more likely to suffer from brake fade if the brakes are used hard for longer periods. More experienced GT3 drivers (no disrespect!) are able to drive around the problem in the UK (by braking harder for shorter time) however we don't have ambient temps anything like as high as yours so I suspect that plays a big part. There are kits available for the MKI to improve the brake cooling.. Again, give the guys above a call - im sure they will ship internationally.
Thats about it but they are great cars to play with on track & im sure you will have many hours to experiment. One last important note.... Make sure you pump the tyres up to normal pressures before you drive home otherwise you can destroy the inner edges in less than 100 miles.
Enjoy
Steve
>> Edited by Merritt on Sunday 9th April 19:57
interloper said:
The bits of melted rubber on your tyres may well be bits picked up by your warm tyres off the surface of the track, not an uncommon on ocurence trackdays.
And you'd were an F1 driver, James Allen would now waffle on for twenty minutes about how that's good because the weight of your car is marginal after a race so every gram you can pick up on your way back to the pits is vital...
Merritt,
thanks for the reply/advice.
There are cracks radiating from the drilled bits of the front discs, but I've read somewhere that as long as they don't join up, it's alright?
I have contacted Alcon about their setup for the Mk.1, but in the meantime, I will try out some higher temp pads (I thinking of EBC reds, any reccommendations?), SS brake lines and higher temp brake fluids, and see how those hold up. Oh, and an improvement in my driving/braking technique too, of course!
I appreciate that I'm a complete novice 911 driver, but the great thing is about the car is that it feels (to me) to have so much potential, that through experience and driver training, I'll be able to make it dance!
Thanks for the tyre pressure reminder; no wonder my inner edges are feeling quite a bit shallower than the outers; damn!
thanks for the reply/advice.
There are cracks radiating from the drilled bits of the front discs, but I've read somewhere that as long as they don't join up, it's alright?
I have contacted Alcon about their setup for the Mk.1, but in the meantime, I will try out some higher temp pads (I thinking of EBC reds, any reccommendations?), SS brake lines and higher temp brake fluids, and see how those hold up. Oh, and an improvement in my driving/braking technique too, of course!
I appreciate that I'm a complete novice 911 driver, but the great thing is about the car is that it feels (to me) to have so much potential, that through experience and driver training, I'll be able to make it dance!
Thanks for the tyre pressure reminder; no wonder my inner edges are feeling quite a bit shallower than the outers; damn!
The Necessary said:
Merritt,
thanks for the reply/advice.
There are cracks radiating from the drilled bits of the front discs, but I've read somewhere that as long as they don't join up, it's alright?
I have contacted Alcon about their setup for the Mk.1, but in the meantime, I will try out some higher temp pads (I thinking of EBC reds, any reccommendations?), SS brake lines and higher temp brake fluids, and see how those hold up. Oh, and an improvement in my driving/braking technique too, of course!
I appreciate that I'm a complete novice 911 driver, but the great thing is about the car is that it feels (to me) to have so much potential, that through experience and driver training, I'll be able to make it dance!
Thanks for the tyre pressure reminder; no wonder my inner edges are feeling quite a bit shallower than the outers; damn!
No probs.
With regards to the official porsche technical bulletin, the discs should be replaced when the cracks have reached 5mm in length OR if any of the cracks reach the outer edge of the disc.
Pad wise, in the UK a lot of us run Pagid RS29 - they are an endurance racing pad and work very well.
Cheers
Steve
The Necessary said:
Merritt, Thanks for the tyre pressure reminder; no wonder my inner edges are feeling quite a bit shallower than the outers; damn!
Unfortunarely the higher pressure won`t cause inner tyre wear. It would cause middle tyre overheating / wear. The inner wear is too much camber on the wheels and / or driving the car too gently round corners !
Re: the brakes you shouldn`t have to be fiddling with brake lines and stuff like that. Just brake hard and for a shorter time. You mention progresssively applying the brakes, that sounds like you are using them for a long time. Also remember to cool the brakes down nicely for a couple of laps if necessary, that means driving round nice and steadily (whilst still maintaining sufficient speed to blow a bit of wind through them), and trying not to use the brakes.
Henry
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