Miata Mailing List: October 1998, Message #172

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Hi guys,

Just came back from my trip to southern Calif.  Project RX-7 spent the 
day at Cooltech in Lawndale, where Jeff Hayes installed 1/2 of the rx7 
prototype brake upgrade package.  Since its for SCC mag project series, 
the brake upgrade was... well, a bit excessive.  Then again, I guess you 
can't really argue that a car can brake *too well*.

FYI, in stock form, the 3rd gen RX7 comes with big four piston calipers 
up front and beefy 11.6"x.85" rotors on all corners. Very good brakes as 
it is.

The guys only did the front brakes today.  The rears will be done in a 
couple of weeks on my next visit.

Front brakes were upgraded to 14"x1.125 Metal Matrix Composite (MMC) 
rotors with specially machined red 911/966 Turbo Brembo 4 pot calipers.  
MMC, rotors, BTW, conduct heat 5x as fast as traditional iron rotors.  
The are also 1/3 the weight of comparible iron rotors.  The rotor holes 
are not "cross drilled", instead, they are actually cast in the rotor to 
prevent fractures, weakening, and irregularities.  Stainless steel lines 
all around, of course.  The brakes just barely managed to fit in the big 
Volk TE37 wheels.  There is almost no gap between the rims and the 
rotors.  They are so big, it almost looks strange...

Cooltech also uses their own proprietary brake pad.  Just one kind of 
pad is necessary for the MMC rotors.  There is no need to swap pads 
between race and street.  Very trick.  When used, the rotors turn a 
light, shiny grey color.  They cannot warp, crack, or groove.  In fact, 
they never have to be replaced in the life of the car, even under heavy 
track usage.  Pads also last longer and dust less.  Downside for the 
package is total cost.  The MMC rotors are more expensive than the 
Brembo iron rotors.  Final prices are set yet for the RX7 package.  It 
is likey to include a 13.5" rotor and a Brembo monoblock 4 pot caliper.  
No ready kits for Miatas yet.  If you are interested, call Jeff Hayes at 
Cooltech.  You should have larger wheels, of course.

Performance, as far as I can tell on the road, is awesome.  No 
discernable fade even after several repeated 100-0mph ABS induced 
breaking.  There is enough braking hp to include wheel lock (and ABS) at 
any speed I've tested (up to 125mph, so far).  No drama, no side-to-side 
motion.  Absolutely no pedal travel, either.  The pedal depresses the 
typical 1" before the brakes grab.  But when they grab, the pedal stops 
and you modulate purely with static pressure.

There is no noticeable difference between cold and hot operation, from 
what I can tell so far.  The rotors operate much cooler than stock iron 
rotors.  Just 2 minutes after repeated high speed stops, the rotors were 
cool enough to touch.  After 5 minutes, they were actually cool (not 
even warm).  Just sick.

The SCC guys and I did some braking hp measurements before the upgrade 
(with Hawks/SS lines/Motul).  We'll compare results when the new brakes 
thoroughly break-in.  It'll be in the mag, of course.

I'm going to test them out all day at Thunderhill this Sunday and then 
again at the Streets of Willow on Wednesday.  I'll post results.  

___________________

Oh yeah, I little sneak preview of one of the Feb SCC featurs I'm 
currently working on.

Mazda Miata Sport package versus Integra Type R
**Tested/timed in autox and and race course (Streets of Willow)

Two editors and I get to flog both cars (and the RX7 for Project 
evaluation, of course) all day on the Streets of Willow in a few days.  
Tough job...

Oh yeah, there will also be another list member's Miata featured in Feb 
issue.  

-Shiv