[s-cars] Re: Big Red Rear Brakes

[Leigh Anderson]

Hi Todd,

I have a few thoughts, btdt for putting big brakes on back of an UrS6...
I'm skeptical of the performance benefits for such a front-heavy car as
ours, but if motivation is 'cause they look great... thats cool, go for it,
being a big brake fanatic myself.  But I just couldn't justify the expense
for myself for functional reasons.

btdt/background: For hard braking anywhere/track use especially, i predict
the best setup will be to use a brake bias control and defeat almost all of
the BR rear brake's capability. my BTDT is an UrS4 track car with mov'it
BR's up front (works great and much better than smaller P-car (968) brakes
that PO put on), and P-car brakes on rear (968) installed by PO, smaller
than the 993tt rears, but much bigger than stock UrS rears. When i tried a
few laps set even 1/3 to rear, it was truly scary/dangerous, the car was
skittering/jittering all over, very un-nerving, with lots of quick-steering
inputs to keep it semi-straight and ABS helping as much as it could but not
nearly enuf. As soon as i slapped the control back to full-front, the car
was rock-solid, much more usable/powerful straight-line braking resulted.  I
experimented a few more laps doing a-b testing and came to a firm
conclusion, at least for that car.

Also note the usual pad life (long) of rear pads vs. front pads under street
or track condition. My R4S street compound pad lasts a long long time at
rear thru street and track use.

so my 2cents is... if function is the goal, consider not to do it, save
money for a more functional perf upgrade.  If aesthetics is the goal, go for
it, but most likely expect to be defeating the rears with a
brake-positioning valve for safety reasons.

pardon if my 2 cents is obvious, as the reference in Todd's post already
says "Some strong words of advice: *-Altering the brake system on your car
may be dangerous, and the front/rear brake ratio should be checked after
modifications. A wrong setup results in locking the rear wheels prior of the
front wheels which is dangerous. I strongly recommend the installation of an
adjustable proportional valve instead of the original one, or at least check
the front/rear ratio with the stock valve."

Cheers,
Leigh
street car: '92 UrS4 with...
   Front: Mov'It BR's, Porterfield R4 pad for track, Porsche street pad (R1
slicks for track)
   Rear:Audi stock caliper rear, R4S pad for track or street, 2Bennett
drilled rotor (R1 slicks for track)

P.S.  note the benefits of <clipped> posting.  I see too many unclipped
posts, one reason i participate less than in past years... it gets tiresome
'wearing out my scroll button' going through digest emails looking for msg#n

----- Original Message ----- >
Message: 1
> From: "TODD KRAMER" <toddekramer at msn.com>
> To: <CaptMagu at aol.com>
> Cc: "s-car-list" <s-car-list at audifans.com>
> Date: Sat, 18 Oct 2003 21:04:40 -0600
> Subject: [s-cars] Big Red Rear Brakes

> Hap,
>
> Send me the pic/pics.  I too am so close to a big red rear brake solution
t=
> hat it isn't funny ... I am simply an emergency brake cable away from
using=
>  the actual RS2 setup with the internal Porsche drums.  The master
cylinder=
>  capacity is my only concern, but my techs in Germany assure me that the
Ur=
> S MC is up to the task.
>
> My biggest hurdle was the centering disk to keep the 993TT rear rotor
prope=
> rly centered, but my OZ Futura's have an integrated removable spacer that
w=
> ill soon be cut to handle the task.
>
> This old link
http://www.s-cars.org/urs4s6/faq/f008/RS2_e-brake/rs2_e-brake=
> _4.html has been the inspiration, but I think Joern was using a true Big
Re=
> d front caliper in his mod.
>
> .=2E.and now that I hear the Lincoln LS uses and electronic acutator on
the=
> ir e-brake, the cables may no longer be the long pole in this tent.
>
> Todd Kramer
> '95 S6