[Biturbos4] Stock Brake Upgrade

Michael Benno mbenno at yahoo.com
Tue Nov 23 17:28:48 EST 2004

Mark thanks for the objective feedback. I have some additional question on this thermal capacity issue... 
I thought the weak thermal link in the system was the OEM rotor and that going to just about any other aftermarket rotor dealt with common warping.
I don't understant how the caliper has poor thermal capicity, does it have something to do with the pad size vs. pistion size?
Also, would a OEM sized floating rotor (eg ECS tuning) deal with the thermal issue as well. My understanding is that composite rotors have better venting. Plus the dual material prevents warping common in the stock rotors.

AudiBiTurbo at aol.com wrote:
Although I sell Stoptech brakes, I might be able to offer some advice on the 
solutions you're seeking. The core problem with the stock S4 brakes is lack 
of thermal capacity. A higher temperature pad over stock will help with fade 
but may aggravate the core situation. I instruct for ACCNA as well as other 
clubs, so my focus tends to be for very aggressively driven cars. For the 
street, a minor upgrade should suffice.

On the front brakes, you're limited to a small number of aftermarket rotor 
manufacturers but several pad manufacturers. The stock S4 rotors aren't of bad 
quality but are expensive. Zimmerman is an excellent and reasonably priced 
alternative. They have the added benefit of slotting which should help with 
surface cooling. For street use, I generally recommend a higher temp pad than 
stock, since the entire system lacks thermal capacity, a higher temperature pad 
will at least stave off pedal fade. Some southern USA customers run lower 
temp "track pads" on the street (with the associated noise and extra wear). 
Generally, a pad marketed for autocross usage will be a good choice, especially in 
colder climates. Also, "track pads" generally start to have point corrosion 
when exposed to winter climates, which can accelerate "chunking."

For the rears, customers with a stiffer spring rate than stock in the front 
can benefit from an A8 rear disk conversion. The stock calipers and pad sizing 
is utilized, but with the A8 rotor and bracket, the caliper is moved further 
out from the center of the hub, increasing rear brake bias. The brackets are 
a dealer item and are installed with some common sized washers as slight 
spacers. Of course, the brackets are a one-time upgrade cost.

Good luck, and sorry that I can't recommend a European supplier.

Mark Rosenkrantz
AudiBiTurbo at aol.com
Binghamton, NY USA
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