Cayenne turbo brakes!

[JAAY]

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]

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

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

[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.

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.

[Pat]

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]

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

[ekam]

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]

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]

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.

[Pat]

Originally Posted by ekam

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.

I've had my eye on the Performance Friction rotors. That may be a good options for me. Any feedback on them? What pads are you using and what kind of track time, if any, do you see?

Cloudsurfer, I'd love to talk with your buddy that's making rotors. Please keep me updated with any info you have. TIA!

[ekam]

I like the PF rotors since they're only dimpled which is way less likely to crack than cross-drilled rotors. I only found out after I received them that their hats are not made of aluminum due to lack of strength & restriction in size. I had them coated since they're not coated (bad for winter) as well.

I'll be doing some track with them on stock pads, and provide some feedback.

[Pat]

Originally Posted by ekam

I like the PF rotors since they're only dimpled which is way less likely to crack than cross-drilled rotors. I only found out after I received them that their hats are not made of aluminum due to lack of strength & restriction in size. I had them coated since they're not coated (bad for winter) as well.

I'll be doing some track with them on stock pads, and provide some feedback.

Great. Thanks, ekam.
I just got off the phone with PF. They said the shipping weight for one of their Boxster S rotors is 22 pounds. The weight of the rotor itself is 18 pounds. I think that four pound difference is the hat, hardware and packaging. For reference, shipping weight of the Zimmerman rotor is 27 pounds.

Losing about six pounds per corner with PF rotors and about nine pounds per corner with OZ Alleggeritas would make a BIG difference.

Whatever rotors I do go with will be used year-round in CO. Can you tell me more about how and why you treated the hats? I would only use the PF rotors if the hats will last many years.

[ekam]

I had them nickel and zinc plated. See link below for the various processes.

http://activemetalfinishing.com/processes/

[Cloudsurfer]

Originally Posted by ekam

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.

I'm well aware of the GiroDisc, and think they're great, but certainly pricey. I am also aware that the PFC rotors are not aluminum hatted, so I'm not sure that you get a significant weight reduction by using them.

My friend (who has a full CNC machine shop) is talking about designing aluminum hatted floating rotors, at an end user price point much less than $1200 a pair.

[Pat]

Cloudsurfer, did you read my post. The PF rotors save about six pounds per corner. That is absolutely significant.
That said, I'd love to hear what your buddy comes up with.

[Cartel]

Originally Posted by Cloudsurfer

I'm well aware of the GiroDisc, and think they're great, but certainly pricey. I am also aware that the PFC rotors are not aluminum hatted, so I'm not sure that you get a significant weight reduction by using them.

My friend (who has a full CNC machine shop) is talking about designing aluminum hatted floating rotors, at an end user price point much less than $1200 a pair.

It appears by the end of next week I will be taking this route if all works out well. Wish me luck!

[insite]

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]

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]

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

[insite]

Originally Posted by stephen wilson

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

activating the ABS on a race track generally results in LONGER braking distances. good drivers will seek to reach, but not breach, impending lockup.

my buddy was not liking the ABS behavior in his EVO, so he removed the fuse & went out on track at road atlanta. hilarity ensues:

http://www.youtube.com/watch?v=Ex1Rzua4Xa8

moral of the story: leave the fuse IN

[stephen wilson]

Thanks for the info. I'll have to try the ABS fuse trick on my truck. It wouldn't stop worth a damn in the snow last winter, because the ABS cuts in way too early.