[s-cars] Re: Vanity Brakes

QSHIPQ at aol.com QSHIPQ at aol.com
Mon May 5 08:52:42 EDT 2003


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[ Picked text/plain from multipart/alternative ]
Frank:
Back in the days when Carl and I started the Big Red phenom for quattros
(look at what we started:), ur-p's, we also looked hard at rear brake setups
to compliment 993tt's.  Then Justy got out his handy calculator, and we
bagged the project.  Audi publishes 80/20 f/r weight distribution for the
quattros under maximum braking with stock brakes and stock tires.  On a
3800lb S car, that means that the rear brakes need to support less than
800lbs of brake loading.  Add more front braking force (ala big reds) with
more tractive ability (better tires) that becomes even less braking on the
rears.  Even the mighty S8 at 4200 large with it's faux Big Blacks, uses the
same rear brakes as the stock S car.  For good reason....

So...  IMO/E putting anything more than the stocks in the back of these cars
is a vanity argument.  There are a lot of issues that add to the cost of that
vanity, and without any performance gain, I just don't see the worth...  For
more "performance" gains in the back, cryro/slot the rears, and put really
agressive pads on the back, really going wild, a couple of ducts.  I've
personally serviced a couple of track/street abused S cars in my shop, and
the rear pads wear more, but the rotors will last longer than any Big Red
front rotor.

WRT the 850 Volvo, that was the one Carl and I had set our sights on in terms
of fitment at the time (1995?).  I'll try to dig up that information if there
is any real interest.  I believe the only issue was the redrill of the rotors
themselves for 5x112, the bracket was a no brainer.

IF you are going to go after anything that doesn't incorporate a rear parking
brake arrangement, I'd think twice about the whole idea.  A lot of grey areas
(in terms of liability) comes into play for subsequent owners.  Carl and I
actually looked at those slick line locks found on Haperfly-tm Cessnas to
replace cable actuation.  At some point better judgement got to the both of
us.

Yes, the SQ uses huge rear brakes.  This is a homog issue, as well as,
locking differentials adding to that ideal brake force distribution.

I chuckle thinking about one of our conversations when I suggested that a SS
disk be put between the actual brakes and the wheel.  Better vanity B4B.

HTH

Scott Justusson
QSHIPQ Performance Tuning
Big Reds aplenty - I'll take the fronts only pleez


In a message dated 5/4/2003 11:42:16 PM Central Daylight Time,
fjamoroso at webtv.net writes:

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Sorry for the tardy response and the WOB because of it...

What works in the back? There are only three solutions that I know of /
that are in the works...

1) Mark S's setup that mates a stock Audi rotor (I forget which one off
the top of my head) with a spaced factory UrS rear caliper.

2) Hap's system in R&D which includes a mechanical spot parking brake
caliper and rear 993 TT calipers that have had the mounting ears
machined off and repalced with radial mounts and custom brackets (IIRC),

3) Rick Barrett's R&D which includes mating the RS2 rear caliper carrier
to the C4 rear wheel bearing carrier and 993tt reear calipers, rotors,
and internal drum brake parking brake setup.

Please note that in the case of #3 above you do not have to run Porsche
5/130 hubs as you can redrill and use an adapter to run the Porsche
rotor on the 5/112 hub.

On the 850 caliper this is news that I had gotten from Carl Jerritts way
back in the day. It was never verified, so I couldn't say for sure
(Scott J., can you opine?).

For my money, #1 is probably the easiest, and #3 the most elegant, yet
pricy. The 850 thing is 1/4 baked at best.

Frank at s-cars.org





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