[s-cars] 16" Avus wheels and ECS Stage 3

[Taka Mizutani]

What I was saying is that braking power of a UrS Boxster setup is
significantly less than the 993tt setup.

You're also comparing the undersized and IMO, inadequate US-spec brake setup
to the Boxster setup. Keep in mind that Euro-spec UrS cars started with UFO
brakes around 315x25mm and then later upsized to the Lucas-Girling 2-piston,
4-pad brakes 321x30mm (IIRC on the exact size), which is what is found on
the A6 2.7T, the S4tt, etc. Audi obviously felt that the G60 setup was not
appropriate for use on the C4 chassis S4/S6, with the exception of the US
market, the justification being that US top speeds were legally at most
65mph.

I've exceeded the heat capacity of my brake setup at the track (Watkins
Glen), but that was with Ate Super Blue and Hawk HPS street pads. This is
with 320x30mm MBZ SL600 rotors and 996 calipers. I don't think that would
happen with race pads. Also, MBZ rotors of that type are directionally
vented, which cool better than the stock Audi rotors which are symmetrical.
At least I don't have Corvette Z06 rotors, which are directionally vented in
one direction only but are used on both sides of the car (!), which is about
the most retarded thing I've heard in a while.

Taka




On Wed, Sep 16, 2009 at 12:35 PM, <racingiron at comcast.net> wrote:

> Taka wrote:
> > Getting a Boxster caliper and appropriately sized rotor is not
> > going to improve your braking significantly, if at all- the pedal
> > feel will improve over a sliding caliper brake setup, but your
> > stopping power is going to be significantly less.
>
> That's a bit of hyperbole there, Taka.  You may not get *significant*
> improvement on a C4 chassis, but it will certainly be better.  An
> "appropriately sized" rotor for a Boxster caliper is something in the range
> of 298x24 (stock boxster).  That compares favorably to the G60 276x25.
> Those running Boxsters on an urS are likely using an Audi 312x25 rotor,
> which, though adding rotating and unsprung mass, also has a larger heat
> capacity.
>
> "Stopping power is going to be significantly less"?!  Sorry, but I'm a bit
> confused by that comment.  My only personal experience with the Boxster
> brakes is on my urq with a 300x25 rotor.  That setup beats the G60 hands
> down, both on the street and the track.  I'm sure the heft of an urS is
> easily capable of overwhelming a Boxster package when pushed hard, but I'm
> confident in saying that the stock system would be well beyond overwhelmed
> at that same point.
>
> Eric R.
> '86 urq
> '92 urS
> '93 urS
>