Cayenne turbo brakes! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

JAAY · 05-13-2010, 06:35 AM

I was at a friends house last night and she showed me her big brake kit she is putting together for her Audi TT. She got a set of 6 piston calipers and rotors from a turbo cayenne. Theres a company that makes an adapter for her car to make them fit. Will Cayenne brakes fit on our cars? HMMMMMM....... I want 14 inch rotors

Boxtaboy · 05-13-2010, 06:46 AM

Maybe not such a good idea. Read this Jay...

http://www.ppbb.com/phorum/read.php?19,1567091,1567302#msg-1567302

Cloudsurfer · 05-13-2010, 07:15 AM

The key to effective brake upgrades is maintaining brake balance front to rear, which the better kits do (think StopTech, Brembo, AP Racing, etc). Race cars work around this by having cockpit adjustable brake bias valves, but on a street car, you want to maintain the factory balance front to rear. So, if you increase braking power 40% up front, you need to add 40% to the rear.

The issue in upsizing only one end is that you have not only upset the balance of the car, but also the way the ABS system behaves.

As others have said, you do not need bigger brakes. What would be nice, would be be aluminum hatted floating rotors, but the stock calipers (even base) are plenty big enough. Run good pads and fresh, good fluid and you're fine.

Now, could you get Cayenne brakes to fit? Sure. You may or may not be able to use the rotors (not sure if the Cayennes use 5x130 or not, since they came from VW originally), so custom rotors may be required, then design and produce a mounting bracket for the caliper, and off you go. You would likely need 19" wheels to clear the calipers.

insite · 05-21-2010, 06:32 PM

Quote:

Originally Posted by Cloudsurfer

The key to effective brake upgrades is maintaining brake balance front to rear, which the better kits do (think StopTech, Brembo, AP Racing, etc). Race cars work around this by having cockpit adjustable brake bias valves, but on a street car, you want to maintain the factory balance front to rear. So, if you increase braking power 40% up front, you need to add 40% to the rear.

this statement is a bit misleading. let's assume that by 'increasing braking power by 40% up front' that we actually have the grip to do this. what happens under full brake load? the nose dives and the rear lifts. when we lose weight at the rear of the car, we lose grip & in turn, braking capability. it sounds counterintuitive, but adding braking capability to the front of the car requires a DECREASE to braking capability in back to prevent rear-bias lockup.

that having been said, street cars are fairly front biased for this reason. accordingly, one can get away with adding LOADS of front braking capability and the rears don't lock up unnecessarily. with race rubber, a problem MAY develop, but it's easily remedied by running different compounds front to rear.

finally, ABS can deal with these mods without any real problems in most cases. issues DO develop if you run tires w/ markedly different grip front to rear.

insite · 05-21-2010, 06:36 PM

just read pedro's story; seems he learned this lesson the hard way. glad he's alright.

FYI, i run 996 calipers and disks front and rear. i use different compounds to modify my brake bias. this is a bit trial and error. as a rule of thumb, a stickier tire requires a pad w/ less friction coefficient in back. pay attention to heat curves! different pad materials get WAY grippy at different temps.

stephen wilson · 05-22-2010, 07:25 AM

I've never raced a car with anti-lock brakes, can you "activate" the ABS system in every braking zone? My gut feeling is that "getting into" the ABS that often will overheat the system, and brake fluid.
Steve

Pat · 05-13-2010, 07:17 AM

Great idea if you want to look cool. If you want your car to perform stick with the stock setup and use good pads and fresh fluids.

JAAY · 05-13-2010, 07:47 AM

I just thought it was interesting...Not going to do it. But would be awesome to see some 14" rotors on a box.

ekam · 05-13-2010, 07:49 AM

Saw a guy with a TT on the track using those brakes on Saturday. Not sure what he's got on the engine but with coilovers/H&R F+R sways he was damn fast.

He had to get special 2-piece rotors which costs him $2k for the whole set.

Cloudsurfer · 05-13-2010, 04:40 PM

A friend of mine (who does race car fabrication) is working on developing floating rotor kits for our cars, which should be MUCH more attractive than $2k a set.

ekam · 05-13-2010, 05:43 PM

Quote:

Originally Posted by Cloudsurfer

A friend of mine (who does race car fabrication) is working on developing floating rotor kits for our cars, which should be MUCH more attractive than $2k a set.

Giro Disc already makes them. About $1200 a pair and they're quality. Only thing is you need 18" to clear the caliper.

PFC also makes a direct drop-in 2-piece rotors for approx. $750 a pair which I have, they will be on the car this summer.