Brake Mods
#1
Brake Mods
I am planning to do some moderate mods to my front brakes. I was quite disappointed with the stock brakes (but I think I had an air problem). Even so, I was struggling with high temps (even with GT-3 cup scoops) so with 600hp, I am really concerned about cooking them on a short track like Gingerman. My TA front end will give me some more ram air to work with for additional cooling, but I don't think it will be enough.
I am going to go with 13.8" floating rotors but stock pads and calipers and aluminum hats. This will give me more rotor area for cooling and slightly more leverage on the front brakes. This will effectively increase my front brake bias (which I think is already too high) and further sub optimize my rear brakes, so I am thinking of staying with Pagid blacks (RS-14) on the front and add Pagid grays to the rear. These are super high coefficient pads that should move the bias closer to the middle. Any thoughts (besides saying save my money and don't brake so hard)?
Yes, I will try them on the skid pad first in case they shift the bias too far to the rear. The problem I am having now is I often try to stay out of ABS mode and if I modulate below that, the front will go to ABS well before the rears ever do so I am leaving rear braking ability on the table and I want to get it back.
I am going to go with 13.8" floating rotors but stock pads and calipers and aluminum hats. This will give me more rotor area for cooling and slightly more leverage on the front brakes. This will effectively increase my front brake bias (which I think is already too high) and further sub optimize my rear brakes, so I am thinking of staying with Pagid blacks (RS-14) on the front and add Pagid grays to the rear. These are super high coefficient pads that should move the bias closer to the middle. Any thoughts (besides saying save my money and don't brake so hard)?
Yes, I will try them on the skid pad first in case they shift the bias too far to the rear. The problem I am having now is I often try to stay out of ABS mode and if I modulate below that, the front will go to ABS well before the rears ever do so I am leaving rear braking ability on the table and I want to get it back.
#7
I posted this a week ago.
The factory steel brakes measure up at:
Front - 13 inches (330 mm)
Rear - 13 inches (330 mm)
With a braking force equal to 1680 HP.
There is three aftermarket and one factory Brembo upgrades for a 996TT:
Brembo GT (Gran Turismo) 4-piston:
Front and Rear
Price: $4995.00 (Front), $3295.00 (Rear)
Front - 14 inches (355 mm)
Rear - 14 inches (355 mm)
Brembo GT (Gran Turismo) 8-piston:
Requires 19" wheels or custom 18's, but don't quote me on the custom 18", I've yet to see it happen. IIRC KPV is working on it with Fikse.
Price: $4995.00 (Front), $3295.00 (Rear)
Front - 15 inches (380 mm)
Rear - Same as above.
Brembo GTR:
A.W.E. sells this kit and Sharkster has them on his car.
Price: $12000.00 (?) Not sure
Front - 15 inches (380 mm)
Rear - 13 inches (328 mm)
Other Choice is PCCB's:
Price: $9995.95
Front - 15 inches (380 mm)
Rear - 13 inches (328 mm)
StopTech also has an upgrade for the TT.
Price: $4495.00 (Front and Rear)
Front - 14 inches (355 mm)
Rear - 13 inches (332 mm)
The factory steel brakes measure up at:
Front - 13 inches (330 mm)
Rear - 13 inches (330 mm)
With a braking force equal to 1680 HP.
There is three aftermarket and one factory Brembo upgrades for a 996TT:
Brembo GT (Gran Turismo) 4-piston:
Front and Rear
Price: $4995.00 (Front), $3295.00 (Rear)
Front - 14 inches (355 mm)
Rear - 14 inches (355 mm)
Brembo GT (Gran Turismo) 8-piston:
Requires 19" wheels or custom 18's, but don't quote me on the custom 18", I've yet to see it happen. IIRC KPV is working on it with Fikse.
Price: $4995.00 (Front), $3295.00 (Rear)
Front - 15 inches (380 mm)
Rear - Same as above.
Brembo GTR:
A.W.E. sells this kit and Sharkster has them on his car.
Price: $12000.00 (?) Not sure
Front - 15 inches (380 mm)
Rear - 13 inches (328 mm)
Other Choice is PCCB's:
Price: $9995.95
Front - 15 inches (380 mm)
Rear - 13 inches (328 mm)
StopTech also has an upgrade for the TT.
Price: $4495.00 (Front and Rear)
Front - 14 inches (355 mm)
Rear - 13 inches (332 mm)
Last edited by dbelleperc; 07-27-2004 at 02:44 PM.
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#10
There may be a sport ABS system?
Some time ago when I had a 1995 C2 I upgraded the brakes to the "Big Red Turbo" which were a bolt-on to that car. I had some of the same impressions you do of the changed bias and performance potential, viz. where the ABS cuts in etc.
A well know autocrosser had done the same thing earlier and found that there was a "sport" ABS brain that Porsche used in the sporting factory cars like the supercups etc. I purchased this and had it installed. It actually changed the percent front to rear hydraulic force bias mechanically and had a different performance profile electronically for the ABS "kick-in", as I recall.
I'd research some cup car people and also ask around if the GT-3 and/or GT-2 ABS systems might have a different bias set and programming?
Having said all of this I find the stock brakes with metal lines and bled well to work pretty dog gone good. The only addition I've done is to go to ATF blue and I would repeat the efficacy of a really good hydraulic system bleed. I have purchased the larger GT-3 vents but due to some recent knee surgery haven't had a chance to install them.
Last word of my experience on brakes and then I promise to shut up. I have found that when you fry the pads or boil the fluid it's really over! They don't come back, they stay spongy for the whole session/weekend until rebled or the pads have been replaced. And this usually happens (for me)at the end of the first straight of the first session, my depth perception hasn't been sharpened by some laps and I go flying WAY too deep into the first corner, jump all over the brakes, fry the pads, boild the fluid, and complain about my "understeer"!
Moral of my PERSONAL story, the first two laps are exploratory and I try to work up to speed.
Anyway I'd be intrigued to find out if a sport ABS system is around? :rolleyes
A well know autocrosser had done the same thing earlier and found that there was a "sport" ABS brain that Porsche used in the sporting factory cars like the supercups etc. I purchased this and had it installed. It actually changed the percent front to rear hydraulic force bias mechanically and had a different performance profile electronically for the ABS "kick-in", as I recall.
I'd research some cup car people and also ask around if the GT-3 and/or GT-2 ABS systems might have a different bias set and programming?
Having said all of this I find the stock brakes with metal lines and bled well to work pretty dog gone good. The only addition I've done is to go to ATF blue and I would repeat the efficacy of a really good hydraulic system bleed. I have purchased the larger GT-3 vents but due to some recent knee surgery haven't had a chance to install them.
Last word of my experience on brakes and then I promise to shut up. I have found that when you fry the pads or boil the fluid it's really over! They don't come back, they stay spongy for the whole session/weekend until rebled or the pads have been replaced. And this usually happens (for me)at the end of the first straight of the first session, my depth perception hasn't been sharpened by some laps and I go flying WAY too deep into the first corner, jump all over the brakes, fry the pads, boild the fluid, and complain about my "understeer"!
Moral of my PERSONAL story, the first two laps are exploratory and I try to work up to speed.
Anyway I'd be intrigued to find out if a sport ABS system is around? :rolleyes
#13
Garey and SLoth, excellent! Someone else is thinking about their brakes.
OK, I also know there are different ABS programs, but this I think is difficlt to change on our cars. The different cars also have different bias valves. I may try to switch bias balves if the different compunds don't work. I have new Pagid RS-14 blacks for the front and Pagid RS-15 gray for the rears. I will probably remove my GT-2 rear brake ducts as I will want higher temps back there for such high temp pads.
OK, I also know there are different ABS programs, but this I think is difficlt to change on our cars. The different cars also have different bias valves. I may try to switch bias balves if the different compunds don't work. I have new Pagid RS-14 blacks for the front and Pagid RS-15 gray for the rears. I will probably remove my GT-2 rear brake ducts as I will want higher temps back there for such high temp pads.
#14
I'll throw out another possibility to you all regarding rotor options. PFC full floating slotted rotors will soon be available to fit the front stock calipers of our cars. The rears will hopefully be available sometime in the not to distant future as well. I am expecting to receive my front set before the weekend. I will be using their carbon carbon 97 compound pads with them.
I had a taste of what they could do about a month ago and was very happy with them. The braking performance was greatly improved, with a firm pedal and no fade whatsoever. It definitely helped to lower my lap times at GingerMan that weeekend. The other amazing thing was that the caliper/rotor temps taken after my sessions showed almost a 150 degree F difference front to rear, with the rears being hotter! Can't wait to get them back on my car.
Tim, looks like I can make it for the August 7/8 event. See you there!
I had a taste of what they could do about a month ago and was very happy with them. The braking performance was greatly improved, with a firm pedal and no fade whatsoever. It definitely helped to lower my lap times at GingerMan that weeekend. The other amazing thing was that the caliper/rotor temps taken after my sessions showed almost a 150 degree F difference front to rear, with the rears being hotter! Can't wait to get them back on my car.
Tim, looks like I can make it for the August 7/8 event. See you there!
#15
Tim, what does Sol say is a good idea? Are your front rotors Sol's? and as far as diff't pads for a diff't bias front to rear, doesn't that screw up the computer that has been taught what the wheels react to based on symmetric pads and "x" applied force for a given decel?