Anyone do the Brembo brake upgrade?

[Maverick]

I understand they sell a set of front discs larger in diameter (floating discs as stock) that work with the Audi calipers (made by Brembo anyway) and an extension kit for the caliper. My tuners here tell me this gives more leverage on the brakes and more braking power.

Has anyone done this? Can you comment on braking effect?

thx

[hmp10]

My guess is that the braking power of the stock brakes already exceeds the tire friction, so stopping distance probably wouldn't decrease exept in rare situations where brake fade of the stockers comes into play I (such as heavy track duty).

Besides, larger front discs would put more unsprung weight on the front of the car and increase the mass near the outside diameter of the wheel, thereby requiring more energy to accelerate and to brake the wheel.

I suspect the Audi engineers chose the disc diameter they chose to balance the trade-offs optimally, at least for street use.

So, unless you're going to track the car, why bother with changing the stock set-up?

[OEMplus.com]

I would agree that the larger diameter discs are primarily to fight fade in competitive environments, but they are also helpful for vehicles with more power.

For example, both the Bi-Turbo RS6 and the Bentley CGT/FS rely on 420mm ceramic brakes for ultimate stopping power. As a car increases it's HP output, the addt'l unsprung weight is offset.

The R8 ceramic brakes are 380mm and the Brembo upgrade is the same. While iron is heavier than carbon/ceramic, I think that Maverick's car had handle it...

[hmp10]

As a car increases it's HP output, the addt'l unsprung weight is offset.

I understand how additional horsepower can counter added weight (at least in acceleration times), but I do not understand what additional horsepower has to do with unsprung weight adding more mass for the suspension system to manage. Isn't that the whole point of the money people spend in search of lighter wheels?

The Audi has superb suspension and handling characteristics and no problem with stopping. 60-0 has been recorded at 96 feet, and brake fade has not been reported to be a problem, even in track testing. Why do anything to erode the suspension dynamics to fix a braking problem that doesn't exist?

[Europrice]

I second the statements by hmp10. Unless you are experiencing fade of the stock equipment upsizing a rotor will merely just add unsprung weight which taxes your suspension. If you are concerned with stopping distances for street driving get the stickiest tires you can find. The stock brakes on the R8 with stock levels of grip will haul it down very well in almost all street situations, you can hit threshold or ABS activation at plenty high of a speed. However if you add traction to the system, you start running higher speeds than spirited daily driving and repeated heavy braking from those high speeds with little cool down time and you'll find fade, quick wear of pads and discs, boiled fluid etc. This usually comes up when you start tracking a car with aggressive levels of traction.

People tend to forget that the biggest factor is slowing a car down in the fastest possible manner is traction and having the brakes be able to reach threshold as quickly as possible from the speed you are starting to brake at. This means that having really grippy tires, a more aggressive pad compound, proper fluid and the rest of the components stock on a car like the R8 will yield good short stopping distances on the street. Now jump on track or drive really hard on a canyon run and you may run into fade. That is when you need to consider solutions, upsized rotors, brake package upgrades, brake ducting (if possible at all), driving more slowly on track (who wants to do this?!), limiting traction, etc.

If you get fade check obvious things first, fluid replace with something high temp like a Motul fluid, step to a more aggressive pad (remember to keep your needs in mind as the more aggressive the pad the more trade-offs, quick rotor wear, no cold bite, etc) and then go out and give things a shot again. If you are still getting fade look at upgrades. Doing something drastic like a Carbon Ceramic is for those who really are going to track often and use the system to it's potential. It also cuts unsprung weight massively, a huge bonus for suspension dynamics.

Cheers!

[Craig@Rennstore.com]

The front rotors with our GiroDisc upgrade - the MAIN BENEFIT is being rid of the god**** holes which crack and groove like crazy....NO professional teams used holed rotors!

$1350 with discount on top of that, and FREE SHIPPING

Disc is on the LEFT:

[hmp10]

While drilling holes in rotors can induce later cracking, my understanding is that rotors that are cast with the holes in them do not experience this problem and are, in fact, what come on production vehicles with ostensibly "drilled" rotors.

I cannot imagine Audi would put rotors on a car such as the R8, which it knows some significant percentage of owners will run on a track, that are prone to cracking. The product liability exposure would be astronomical, as well as the public relations hit to Audi's aspirations in the arena of high-performance cars.

Are R8 stock rotors actually cracking in service, or is this just an urban myth that happens to be good for aftermarket sellers?

[Bodhii]

Are R8 stock rotors actually cracking in service, or is this just an urban myth that happens to be good for aftermarket sellers?

They are indeed cracking under even moderate track use.

[Craig@Rennstore.com]

Well, let me help out here:

Cast in hole rotors (of which the R8 and Porsche are) do indeed crack somewhat less, but the problem significantly remains; stress risers and thermal isues / grooving from having many little holes no longer makes any sense.

The problem is pretty well known amongst track used vehicles that are driven by folks who are beyond the beginner stage.

Customer got 28 HARD track days on GiroDiscs with his GT3...never will happen on a hard driven R8.

Giros on a Porsche:


(BTW even worse is the horrid brake fluid used on OEM R8s)

I'll dig in the external drive for in-use track used holed rotors pictures

[Craig@Rennstore.com]

I took this picture at Daytona 24 hr 2005: