s4 brakes

[AudiBiTurbo at aol.com]

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The S4 rotor "problem" is caused by lack of cooling air flow and poor rotor
design.  They simply can't dissipate the heat.  I call this a "problem"
because it manifests itself most frquently on harder driven cars (like track
useage or a good street driver being aggressive often).  As an aside,
agressively driven 993 Turbos often crack rotors- I've replaced several
cracked Porsche rotors, including 993 Turbo rotors on lighter, older 911s.
In fact, the 911 is easier on front brakes compared to other sports cars due
to good rear downforce and the rear-weight bias.  These allow the rear brakes
to carry a proportionally larger percentage of braking.  This rear weight
bias is why Porsche has always had "great brakes" as well as an accelleration
advantage.

It took me 14,000 street miles (no track time) to warp my first set of S4
rotors.  It took *1* day at Watkins Glen to warp the second set of factory
rotors.  If you fabricate your own cooling ductwork, that would definately
help.  It will change high-speed aerodynamics.  How much?  I don't know, but
I doubt you'd change them that much to make the car un-drivable.  However, in
combination with expensive stock parts and very expensive aftermarket pads to
fit an S4 application, I've been using and selling a lot of Stoptech kits.
Much better (and patented) rotor design (the S4 size flows more air than a
Porsche GT2 rotor!), and front pad application is 993 front, so everybody
makes friction for them... and the track pads I've been using (KPF) cost arou
nd $100. per set.  Long term, if the car is driven aggressively often, it's a
wise invesment to upgrade the front braking system.  If you only don't warp
the factory rotors often, it's safe to stick with the factory parts.  The
only other cost-effective alternative is Porsche calipers on the S4.  These
are really designed for Porsche weight transfers and master cylinder sizing
(bias).  In short, they work, but not ideally.  Stoptech is under $2000. for
comparison purposes.  Hopefully I've helped "shed some light" on the subject.

Always remember- braking is a safety issue, too!!

Hope I've helped,
Mark Rosenkrantz
AudiBiTurbo at aol.com