S2000 Brake Duct Install
By Rob Robinette
After melting two sets of Porterfield R4 brake pads and setting a caliper on
fire I decided I needed to do something to cool my brakes on the track.
Vented disk brakes are designed to cool themselves from the inside. The
vanes inside the hollow disk act like a fan, moving air from the center of the
disk, through the disk then out the outside edge (see disk below).
With the dust shield in place the stock disk gets much hotter on the inside face
of the disk versus the outside which gets cooling air through the wheels. That's
not a problem as long as the temperature change is relatively gradual--no
thermal shock. The ducted air from this mod simply feeds the inside face and
center of the disk cool air, and that's a good thing.
I've run a couple of years with this ducting and it made a huge difference
in brake performance and pad life--this setup works!
I used 2 inch hose because it's much easier to run under the air pump and
gives more tire clearance in the wheel well than 2 1/2 or 3 inch hose. It
doesn't make sense to run a 3 inch hose and then constrict it under the air
pump, then connect it to a 2 inch hole in the dust shield. This 2 inch setup
works well but when I removed my air pump in March 2011 I moved up to 2 1/2 inch
hose and flanges. If you remove the air pump then even a 3 inch hose might be
the way to go but you will get some pretty good tire rubbing if you run 255 or
wider tires up front.
The Finished Product
Melted Porterfield R4 Brake Pads - Why I Added the Ducts
Special Tools: 2 (or 2 1/2) inch hole saw designed to cut metal. You'll use it to
cut the brake dust shields, fender liner, and bumper. Sourced from Home Depot.
8 nuts & bolts for bumper flange. I used black bolts and black plastic
washers to blend into the bumper's black ducts. Sourced from Ace Hardware.
4 nuts and bolts for dust shield flange (or pop rivets)
4 two (or 2 1/2) inch hose clamps
At least 4 fourteen inch tie-wraps
Put the front of the car up on jacks and remove the front wheels. I followed
by Arnell to remove the front bumper. Just remove all the fasteners below, then
pop the bumper loose from the clips under the headlight. Make sure the outside
edge of the bumper is outside the fender liner and pull the bumper straight out
and it will pop loose.
Photo by Arnell
Photos by Arnel
Photo by Arnel
Follow this How-To to remove the brake
calipers and disks.
Running the Ducts
On the driver side of the car you have to run the hose around the air pump.
It is preferable to put the hole in the fender liner about mid level like I did
on the passenger side, but unless you remove the air pump you have to run the
hose on the driver side as low as possible to prevent the hose from being
constricted by the air pump. Be sure and sand down the hole edges to keep them
from eating into your hose. I put a layer of duct tape around the hose where it
goes through the hole, touches the stabilizer bar, and where it's secured to the
Ready to Drill Hole in Left Fender Liner - Screwdriver is
Used to Lift Air Pump Hose
Driver Side Fender Liner Hole
Passenger Side Hole
Use the 2 inch hole saw to cut your hole in the bumper. I used the flange as
a guide for where to place the hole and where to drill the bolt holes. Secure
the flange to the bumper. I used four black hex-head bolts so they wouldn't be so
obvious. I also painted the inside of the flanges black for the same reason. I
had to remove a little metal on the flange to fit around the fog light mounting
tabs. You can also just cut off the tab if it gets in the way.
I used a box cutter to cut the hose and then used wire cutting dykes to cut
the hose wire. Cut the 12 foot hose in two and run the 6 foot sections through the fender liner holes.
This is when I put the duct tape in place to reinforce the hose where it goes
through the fender liner hole.
Painted Bumper Flanges
Clamp the hoses to the bumper flanges. It helps to put the bumper on top of
something to get it close to its mounting location. As you mount the bumper,
pull the excess hose through the liner hole from the fender well side.
Bumper Hose Connection
Pop the fender in place. Make sure the outside edges of the fender are
outside the fender liner, and that the radiator floor pan is inside the lower
lip of the bumper. Once the clips under the headlight pop into place the bumper
is secure. I recommend waiting to put all the fasteners in place until you're
finished with the install just in case you need to remove the bumper again.
The hose needs to run along the inside of the wheel well, then under the
upper A arm to the dust shield. I used 14 inch tie wraps to secure the hose. One
tie wrap around the stabilizer bar mount and one around the shock body.
You can modify the brake dust shields with them mounted on the car, but I
had already cut mine off so I had to source some new shields. I cut them as
shown to allow installation without removing the wheel knuckle.
Use the 2 inch metal hole saw to cut the dust shields. I made a 1/8th inch
pilot hole first to keep the hole saw bit from walking. I cut the hole in the
dust shield as close to the center of the brake disk as possible to send as much
cooling air to the inside of the vented brake disks. Before you drill check for
clearance around the driver side ABS sensor. It was a tight fit for me. For more
clearance you should drill the hole a little more clockwise around the dust
shield than I did.
I bent the outside edge of the dust shields to close the gap between the
shield and disk to prevent air leakage.
Brake Dust Shield Before and After
I trimmed and bent the inside edge of the
flange to help the flange-to-dust shield seal (see below). The aluminum flange
is easy to cut with tin snips and I used a pair of pliers to bend the flange to
fit. I used two 8mm bolts to secure
the flange to the dust shield.
Dust Shield Flange - Notice Lower Edge Trimmed and Shaped
Dust Shield - Brake Disk Side
Before you make the final hose cut, make sure the steering wheel is turned
to full lock to the left for the left side install and to the right for the
right side install for full hose extension. Clamp the hose to the flange, finish
tightening the tie wraps (not too tight though) and move the steering from lock
to lock to verify clearance.
Right (passenger) Side - Steering Full Right for Full Hose
Left Side Steering Full Left - Notice Bend in Dust Shield
Edge for Better Air Seal
Here's an alternate routing option using 3 inch hose and a
tin can (left side of picture) as the hose end aimed at the bare brake disk
(dust shields removed)
Blacked Out Ducts are Barely Noticeable
Don't forget to put all the bumper fasteners back in and follow
the brake How-To to reinstall the brake
disks and calipers. This would also be a great time to bleed the brakes.
Install the wheels and torque the lug nuts to
I recommend at least partially covering your cooling vents during
brake pad bedding. If you don't it may be hard to get the pads as hot as they
need to be.
Drive the car for a few miles and make some full lock turns and then check
the hoses for tire rubbing.
Enjoy those functional brake vents.
March 2011 Update - Up-Sized to 2 1/2 Inch Ducts
I had the nose off the car to do some race prep work and decided to replace
my two inch ducting with 2 1/2 inch. I believe this is the perfect size as 3
inch hoses will be rubbed pretty badly by 255 width front tires. Here's a couple
of pics of the upgraded brake ducts.
Upgraded 2 1/2 Inch Ducting
2 1/2 Inch outlet
2 1/2 Inch Bumper Inlet
Corvette Grand Sport 2006-12 Brake Ducts
These Corvette Grand Sport ducts look like they'd work pretty
well on the S2000. They have a 4 1/2 inch inlet (left in picture) and a 2 1/2
inch outlet. You could insert a 3 or 2 1/2 inch hose into the large input and
run standard 2 1/2 inch hose from the outlet. You'd probably have to have the
air pump removed to make these work. They're only $15 each from:
I'm pretty hard on brakes and this is my take on the S2000
When you change out brake lines or calipers a LOT of air will
be in the system and it will take several bleedings to get it all out. I like to
gravity bleed the day after an event after all the air bubbles have settled as
high in the system as it can get.
Part of the S2000's problem is air will get into the anti-lock brake system (ABS) part of the brake
system and sit there until the ABS pump is engaged and then the air will get
injected into your brake lines. Once you get a spongy pedal you've got to bleed
the brakes several times (and engage ABS prior) to get all the air out.
I think the pad wear rate is your best indicator of when you've
outgrown your pads. As you get faster and brake later/harder you'll overheat
your pads and they won't last very long. Move from stock to HP+ to XP10/XP8 and
you'll actually save money on pads because you won't burn through them so fast.
I like the Carbotech XP10 front and Cobalt XR3 in the rear--I get much longer
wear from the XR3s. I tried the XR2s in front but they melted. I tried XP12s up
front but they really ate into the rotors at an alarming rate.
I've been using ATE Super Blue and 200 (same fluid but amber)
for a long time and I've never had any fade. I usually only flush the fluid
yearly unless I change a caliper or line and the ATE lasts that long. I've never
tried the Motul but I know it's good fluid but it may not handle moisture as
well and therefore last as long as ATE.
This is something I just recently learned. I normally allow the
brake fluid to get lower (but never to the Min level) as the pads wear so that I
don't have to pull any fluid out of the reservoir when I push the caliper
pistons in for a pad change. This worked for me until I really started to push
my car on Hoosiers. With the stickier rubber I'm braking hard enough to slosh
the brake fluid forward which allows air to get sucked into the system. The very
next lap after my personal best around Summit Point the pedal went very soft
entering Turn 10. I was lucky I didn't have a seat bottom cushion in my seat
cause I would have had to pull it out of a lower abdominal cavity! When I got
home I bled the brakes and I had a crap load of air bubbles. Moral of the story,
keep your brake fluid on the high side and be ready to pull fluid out of the
reservoir for a pad change.
The S2000 brake calipers are small and light and can have a
tough time dealing with the heat generated by really hard and prolonged braking
on the track with race compound tires. Venting your front brakes with air ducts
will make your brake pads last much longer and help prevent boiling the brake
fluid. When I put new stock calipers on my car they would heat discolor after a
track session or two. I'm now running much larger and 2 lbs heavier Accord
calipers and they have not heat discolored after about 7 hours of track time.
The Accord XP10 pads are lasting about 80% longer too--I would occasionally
overheat the stock XP10s and they would "smear." If you're pushing XP10 brake
pads you need brake ducts and/or
a caliper upgrade.