[Supras] Want good braking?? (track use pads review)

[Jeff Mohler]

(Same numbers, but unrelated and different manufacturers)

I set Brian up with a balanced affair..

The ST41 is a Raybestos hardcore, race _only_ pad, and the R-41 is a
Porterfield low-temp high-friction compound.

The ST41 makes pretty insane friction levels, but after properly
bedded will not eat rotors, at all.  And will last many times longer
than other race pads.  I have many race only customers lasting 14-18mo
worth of sunny California race schedules on a single set of pads _and_
rotors.  The one that that makes the Raybestos compounds differnt from
other high friction race pads as well, is that they dont come "on"
with the initial touch of the pedal really agressively.  Heavier
faster cars need a moment to let the weight settle to get peak
braking, so the application even when used quickly is very
linear..little pressure = little brake, but BIG pressure = BIG brake,
and very modulation friendly in between.  Which is also key, because
you want to feel your tires as they begin to lock and then be able to
release the brakes to prevent it without having to _disengage_ the
brakes to prevent it.  The difference there is one method is still
slowing the car down, while the other isnt.

The ST41 is the 'big boy' compound, with the ST43, and ST42 serving
other unique purposes.  The 43 works just like the 41, but is better
for lighter cars with smaller rubber as its not as overall aggressive.
 The 42 gear is very linear in it's friction.  It makes about the same
coefficient of friction cold as it does at it highest point.  Which is
great for an application where a wide range of temps are expected
and/or rear solid axles are at play, and you cannot use horribly high
friction pads because of the geometry issues.  I have a handful of
cars in the Mexican Pan-Am starting this week, that need that wide use
conistency of rear braking effort.  Just sometimes you dont want
rising friction with rising temps, because then you have to dork with
your proportioning valve all the time.  And thats no fun.

The Porterfield AP-41 stuff...makes really huge friction, pretty much
race level friction, at very cold temps without the problem of using a
race pad at cold temps, which will eat a rotor gone in weeks.

Brian didnt want to spend a ton of time swapping both ends of the car
for a track day, so we went with that AP41 street pad.  He can still
use it on the street out back just fine, he's getting all of that rear
braking you would experience if you did a loooong hard brake from a
high speed, and then added in the friction effort of the Ebrake to
slow down quicker.  Maybe added another 5-10% bias to the rear without
chainging out any hardware, just the pads.

So..he only has to swap fronts, which aint bad.

But to compare the Raybestos to the ST41?  Its probably 4x the pad,
but its race only, where the R4S is a street only pad that can handle
limited moderate track duty.

About the only remaining problem would be heat.  A 3x more efficient
pad will develop a LOT more heat into the rotors, and they'll crack
from heat stressing quicker.

If there is ever demand for a proper MK3 brake cooling solution, I'll
build it just like I did the bushings.

On 10/15/07, Howard Hutchinson <bighoward at sbcglobal.net> wrote:
> Great report and invaluable feedback Brian.
>
>   I'll assume that the *41 for the ST and R pads are the same compounds, just different manufacturer?
>   How does the dusting compare to the R4S?
>
>
> "Walker, Brian (Rich. Dist)" <Brian.Walker2 at VDOT.Virginia.gov> wrote:
>   Well, I finally got to try out the new pads at Summit Point (WV) this
> weekend. I'm using the Raybestos ST-41 in front and Porterfield R-41 in
> rear (normally using R4S for street/auto-x). The pads did end up scoring
> my rotors which is likely my fault from not breaking them in properly. I
> went easy the first few laps (maybe too easy?) and then got a little
> harder on them but never really standing on the pedal. The second day I
> was dealing with some vibration under hard braking, which made me a
> little timid to really stand on them but when I did it was what I
> thought would require a BBK to feel. At the end of the straight I was
> getting a little annoyed by Miatas and an MR2 for braking so early. Same
> result through the 'chute' (fast downhill into a hairpin) I was finding
> myself going off-line to avoid some other cars. He instructor
> complemented my smoothness but still I'd see him lunge forward at each
> brake application. Not one occurrence of fade either (the pedal got a
> little soft due to the now weak link fluid) but some siding due to
> relearning threshold braking (abs came in much quicker than before so
> the braking pressure had to be relearned)
>
> I could not believe a 3600 lb car could stop like this! It was very cool
> to catch lighter cars in the hairpin at the end of the straight because
> I was able to brake so much later. The really let me be faster
> throughout the track. Got the signoff for solo (group 1) and moved to
> the next group. The R4S stopped well last year (this is my second event)
> but wore quickly, these stopped much quicker. I had visions of coming
> through a downhill sweeper at 80 mph and into a hairpin and sliding
> across the sand/grass skipping a few turns. Instead, plenty of stopping
> power even on street tires! I'll check the wear on these pads and report
> back.
>
> Brian W-88T
>
>
>
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