Brake Information
If you want to upgrade your brakes you've come to the right
place. You'll find very detailed information below on how to perfect the RX-7's brake
system.
The Mandeville Autotech Big Brake
kit with 18 inch Mito Modular wheels
Wet boiling point is the major
specification to consider for brake fluid for street use. Wet boiling point is the
temperature where moisture that has been absorbed into the fluid will boil. When this
moisture boils it fills your calipers and brake lines with bubbles. These bubbles are
easily compressed so your brake pedal gets spongy and you can't apply the same force to
the brake caliper pistons--your brakes fade.
The dry boiling point is the temperature where the fluid will boil
without any contamination present. The cleaner and fresher your brake fluid is the closer
your brake fluid will stay to the dry boiling point. This is why racers always do a
complete brake fluid flush before a race.
This info supplied by the ever knowledgeable Trey Jones:
-
Fluid
DRY WET Minimum Boiling Points °F
Castrol SRF
590 518
Motul Racing 600
585 421
ATE Super Blue Racing
536
392
ATE TYP 200
536 392
Valvoline Synthetic Dot 3, 4 514
333
-
Castrol GT LMA DOT 3, 4 446
311
Ford Heavy Duty DOT 3
550
290
Performance Friction HP
550
284
Castrol SRF is a hyper-exotic and hyper-expensive brake fluid that is
generally used by wealthy Porsche owners at track events. I've seen prices of $78 per
liter for this stuff. It is not suitable for the street because it absorbs moisture
quickly. Sold in metal cans. I can't afford this stuff!
Motul Racing 600 is a very exotic and relatively expensive synthetic
fluid with high wet and dry boiling points. I use this exclusively in my race cars. Too
expensive for the street and requires frequent changing due to its hydroscopic nature.
[Rob Robinette adds: Many people do use this stuff in their street car and it's compatible
with ABS. The bottle says it will last between 12 and 24 months depending upon the
application. That's long enough for me. Sold in plastic bottles at most motorcycle shops
for $12 per liter.]
ATE Super Blue Racing and ATE TYP 200 are the same brake fluid in two
different colors (blue and amber, respectively). BMW recommends this brake fluid for their
street cars because it, like Castrol LMA, absorbs moisture very slowly. The advantage over
LMA is that ATE has a much better wet boiling point. You can put this stuff in your car
and forget about it for a long time. An excellent choice for a weekend track car which
also sees regular street duty. Comes in metal cans. This is what I use in all my street
cars.
Castrol GT LMA is very good at rejecting moisture and may be kept in
your brake system for a couple years. The LMA stands for "Low Moisture
Absorption". This is the minimum quality stuff that I would use in my Impala. It
comes in plastic containers which do not have a long shelf life. Don't buy lots of this
stuff at a time because moisture can make its way through the plastic containers.
Ford Heavy Duty DOT 3 is VERY inexpensive and is popular among racers
because of its excellent dry boiling point. It absorbs moisture quickly, but the racers
don't care since they change their fluid frequently. Comes in metal cans so it may be
stored. I would not use this in my Impala for the street.
Performance Friction High Performance DOT 3 has a good dry boiling
point but a crummy wet boiling point. It comes in metal cans which is good for shelf life
and sells for $7.87 per 16 ounce container. If you are even considering this fluid, I
would go with the cheaper Ford Heavy Duty DOT 3. In either case, change this fluid
frequently due to the poor wet boiling point.
Thanks Trey!
Jon
Roger Mandeville of Mandeville Autotech has race prepped a
lot of cars. He does not recommend cross drilled rotors because cracks form at the holes.
He said some racers run them in short sprint races but then throw away the rotors after
the race. For endurance races his cars use standard non-drilled, non-slotted rotors. Even
rotors that have their holes formed into the rotors when they are cast will crack. He
doesn't recommend slotted brakes either.
Also, my brake light will come on when I drive
hard......... Anyone know why?
This could be your brake fluid close to the low mark. When
you jostle the car around, it could be tripping the fluid sensor. Also, your parking brake
sensor may be loose.
There is a very cheesy switch located to the rear and below the
parking brake lever. Your parking brake warning lamp is illuminating, most likely, due to
one of the following reasons:
Your emergency brake handle is not fully in the down position. There
might also be a foreign object preventing it from going all the way down. Even one
"click" up from the down position can make the light go on and off.
Your emergency brake handle is loose, allowing it to slide slightly
sideways in the down position. This will cause the parking brake switch to not engage
fully.
Your parking brake switch is loose, bad or failing. The console
panel pops off pretty easy, allowing access to this switch. The switch is located just
below the back of the parking brake lever boot. Good luck, hopefully it will be an easy
fix!
Dave
I painted my calipers using Folia Tec brake caliper lacquer (from
Ultra Performance (800) 43ULTRA $49.95). Use a fresh, soft, camel hair 1/4 inch wide paint
brush and heed the temperature range for applying the paint. Summit
racing also sells high temperature caliper paint for a few dollars a can.
|
Hawk
Brake Pads
FERRO-CARBONTM
Racing Friction
Ferro-CarbonTM is a unique, high-tech friction material
developed and manufactured by Hawk Brake for the racing community. All
Ferro-CarbonTM
materials exhibit non-fade performance and have been evaluated up to and beyond 1,800
degrees F. Each material offers lower wear rates and higher torque values than all other
competition materials available on the market today.
Product Line
|
General Description
|
Car Weight
|
Applications
|
GOLD HT-9
|
Highest torque friction available on the market today.
Superior peak feel and initial response. Low wear rate. Lightly climbing Coefficient of
friction, user friendly on hard stops.
Optimal temp. range: 900f to 1800f
Track Surface: Asphalt
|
ALL
|
Winston Cup, Indy Car, Trans
Am, World Sports Car, Super Touring Car, IRL, F3000/Group A
|
o
|
GOLD HT-8
|
Medium torque with minimal pedal effort. 20% less brake
response (Stickiness) then HT-9. Low wear rate at elevated temperatures. Recommended for
Super Speedways and Endurance Racing for Cars over 3000lbs. Excellent rear axle pad when
running HT-9 on front axle.
Optimal temp. range: 900f to 1800f
Track Surface: Asphalt
|
OVER
3000 lbs
|
Winston Cup, Trans Am, IMSA
Endurance, ARCA, Super Truck,Bush GN
|
o
|
BLUE MT-4
|
High torque with minimal pedal effort. Excellent brake
modulation. Simply the best Grass Roots Stock Car pad for Circle Track applications.
Excellent high friction pad for light open wheel cars. Good wear rate. Run on
racing rotors only.
Optimal temp. range: 500f to 1300f
Track Surface: Asphalt and Dirt
|
UNDER
3000 lbs
|
ASA, ARCA, All Pro, Hooters
Cup, Modifieds, Late Model Dirt, Dirt Sprint, Formula Ford, F3000, Saxo Cup, Citroen Cup,
Formula Renault
Aggressive pad for RX-7
racing but not for the street
|
o
|
BLUE 9012
|
The original Hawk Blue pad is material of choice for SCAA
and IMSA Showroom stock racer's. A reliable performer for start to finish. Medium/High
torque with minimal pedal effort. Low wear rate. Excellent brake modulation and Rotor
friendly. Can run against racing and Street Stock rotors under racing conditions.
Optimal temp. range: 500f to 1000f
Track Surface: Asphalt
|
UNDER
3000 lbs
|
Showroom Stock-SCCA, Showroom
Stock-IMSA, Formula Ford, F3000, Saxo Cup, Citroen Cup, Formula Renault
Good for RX-7 Track Events but not for the street
|
o
|
BLACK
|
Pad of choice for Dirt Circle Track applications. High
torque with excellent brake modulation in Dirt Applications. Medium torque with average
wear rate for Asphalt tracks.
Optimal temp. range: 300f to 800f
Track Surface: Asphalt and Dirt
|
Asphalt under 2100
or
Dirt Track under 2900
|
Late Model Dirt, Sprints,
Modifieds, Formula Ford
|
o
|
DR 97
|
Developed specifically for Drag Racing Applications.
Excellent Dynamic and static Coefficient of friction. Low wear rate and rotor friendly.
|
ALL
|
Dirt Racing Only, IHRA, NHRA
|
o
|
HP PLUS
|
High Performance Street material PLUS race worthy.
Excellent Low temperature pad for Dirt racing.
Optimal temp. range: Ambient to 800f
Track Surface: Asphalt and Dirt
|
ALL
|
All Dirt applications,
Autocross, Solo 1 & 2 , Driving Schools
Good
RX-7 Street Front Pad-lots of brake dust
|
o
|
HPS
|
High Performance Street material. Extremely low dust,
Rotor friendly, High friction, Quiet running. Excellent replacement for OEM materials for
improved braking.
|
ALL
|
STREET
Good RX-7 Street Front or Rear Pad
|
|
HP Plus pads in the front and HPS pads on the rear is a good
street/track compromise. Hawk Blues will eat your rotors very quickly when used on the street
(low temperatures). The more aggressive you brake on the track (a function of your driving
ability) the higher the temperature range of your brake pads should be. An average novice
at a track school event would be fine with HP Plus and HPS pads. An advanced driver in an
actual race could use the Blue MT-4 because he would use his brakes hard enough to keep
them their prime operating range.
Last December I participated in my 3rd track event. I went through the same problems
you have encountered in your first experience. To give you my perspective on your
questions:
1) Forget about using street pads for the track and vice
versa. It only takes about 10
minutes to change out both front brake pads and the benefits are enormous. I switched to
Hawk
Blues my second track event and was blown away by the increased stopping power.
In addition, the harder I drive, the better they get. The problem is this ... on the
street the Hawk Blue's run cold and will destroy your rotors. On the track when they get
hot they are great. If you use a street pad on the track, they will fade when hot because
they are designed to run cool and NOT destroy rotors. I personally don't think there is a
compromise. I simply switch pads out and I have the best of both worlds. Also, you only
really need to switch out your front pads. There is little work done by the rear brakes on
a track. The other issue is brake dust. For the track, dust is inevitable, but for street
use, dust can be annoying and damaging to your wheels. I use MetalMasters for the street
and like them. I hear Bonez pads are good for the street. Both produce relatively small
amounts of dusting on the street, however both will fade in track application. Your best
bet, do what I did ... purchase a used set of wheels for the track and keep your good
wheels for street use. Track wheels can look bad, accumulate dust and be just fine. Save
your good wheels for looking good on the street. Hope this helps.
Jon A. Drake
I have run my TII and 3rd gen. at track events for a few years and here is what I have
found. There is no good tire for street and track use. For track only I like the BFG R1's
and now G force tires. I have tried Hawk Blue, Black, HP+, and HPS, Bendix and
Repco. For the track I like Hawk Blue MT-4 pads. Be careful
because there are two types of blues and the Hawk Blue 9012s still fade a
good bit. The other Hawks I found to fade WAY too much for serious braking. (and they suck
on the street). I burned through a new set of Blacks in one weekend. For the street I like
the stock organic pads because they are soft and conform to track grooved rotors well.
Don't run Blues on the street.
If you are unwilling to change brakes and tires for events then a mediocre compromise
would be the Porterfield RE4 pads and pick a tire based on the miles you
drive. If you drive less than 5k a year you could probably get away with a true track
tire. If you drive more, the A032 might be a good choice. My rational is to buy long
wearing street tires to save money, and use the funds to run track tires. Lots of people
are selling used stock wheels. Long wearing street tires also allows you to run more
negative camber without eating up the insides of your street tires. Alignment has a HUGE
effect on handling. The new BFGs are also more negative camber hungry than the old R1's.
Trey Jones
1. Use stock rotors from Mazda Comp or Porterfield ($80/each)
2. Do not allow shops to use air gun to put on wheel lugs and have them properly hand
torqued (over torque warps them 2)
3. Do NOT do a high speed fast stop and immediately come to a complete stop and sit. It
does make a dam bit of difference what kind of rotor you have if part of it is sitting
under the caliper, red hot and cannot cool down at the same rate as the rest of the rotor
because you are sitting still. If nothing else, let the car slowly roll for several
seconds before coming to a complete stop.
4. Try the Hawk HPS (Street) pad. It is more than adequate for street
driving and gives minimum dust. Itll stop you from 150 to 0, no problem. If you are
looking for track level performance (back to back stops as above) then go with the
Hawk
HP Plus or Blacks. Anything more aggressive (like the Blue) are
for the track only, your rotors would likely be worn through before they got a chance to
warp.
5. Slotting and drilling are to vent gas and dust and have no significant effect on
cooling. Drilled rotors do weaken the rotor and make it more likely to crack. Both mod
cost extra and can be done to any stock solid rotor.
6. Use a quality DOT4 brake fluid such as Motul 600 or AP600 and bleed your brakes at
least once a year (full flush of system)
John can comment, but in 13 drivers schools (about 40 hours of track time) with stock
rotors I have yet to have a problem with fade or dust and have used Mazda stock rotors
(HPS pads for the street, Blues for the track).
Hawk HPS - (High Performance Street) pads are good street strip compromise
Gordon Monsen wrote:
Brad,
i use peter farrell's vented/drilled 12.75" rotors with willwood 4 piston
calipers. do you think the porsche brembo offers any notable improvement?
thanks, -Gordon
Yes. To some racers, Wilwood calipers are cost-effective and replaceable. Unlike
AP and Brembo units, the Wilwoods I have seen have no dust seals around the
pistons. While not a big problem, they are not as maintenance-free as the OEM
quality calipers. No big deal if you tear down and go over your braking system
after every race. Wilwoods are also popular due to their availability, price, and
model selection.
Unfortunately, Wilwoods are structurally far less stiff than the AP/Brembo units.
If you have someone pump the brakes while you carefully look at the Wilwood
caliper, you will probably see it flex. You would see no such flex with AP or
Brembo components. There is a cost differntial, of course. A Wilwood 4 pot
caliper costs $65-85 from Jegs. A comparible Porsche/Brembo calipers costs
significantly more (around $300, IIRC) from a Porsche dealer. They are even more
expensive directly from Brembo, from what I've heard.
Caliper stiffness is very critical in performance. A stiffer calipers maximizes
pad life and improves brake feel/modulation. Whether it is worth the extra $$ is
up to the buyer.
FYI, the stock aluminum, lightweight, 4 piston front calipers on the 3rd gen are
very, very nice. You'd be surprised how many "high performance cars" use
heavy
iron calipers with floating pistons. The stock caliper's limitation is that they
can only accept stock-size rotors (11.5"x.8"). [this is why the Mandeville
Autotech big brake kit widens the stock calipers to work with 13"x1.1" rotors]
The smallish stock-sized rotors
can only store so much heat before fade becomes a problem.
The stock pad size is also relatively small compared to aftermarket alternatives.
The larger the pad, the longer its life. No big deal on the street, but in an
endurance race, pad life can be critical. This is why 6 piston calipers are
popular in certain types of racing. They don't brake any better, but the pads can
last 50% longer. Downsides: More fluid needs to be displaced. Inital "bite"
is
also reduced. It's a common misconception than a 6 piston caliper will
"outperform" a comparable 4 piston calipers.
Only when we get into 8 piston calipers, does actual braking performance improve.
This is because 8 piston calipers use 2 pads. Approx. 15% of all braking friction
comes from the leading edge of the pad. Two leading edges-- more friction. Lots
of pad area as well--- longer pad life. Cost a lot though...
As for rotors, Brembo units are very nice. Holes are cast in, not drilled in.
This greatly reduces the chance of stress cracks. They also use very high-quality
iron and are very thick (typically 1.1-1.25"). All things equal, a thicker rotor
is stronger and more fade resistant. They are also expensive, no doubt partly
because of their overseas origins. They are one of the best, nonetheless.
-Shiv
|