IW STi Forum banner

DIY: Brake Cooling for the GD-Impreza

69K views 93 replies 27 participants last post by  got2boostit2  
#1 · (Edited)
I have been running this "pieced together" DIY brake cooling set-up for 2 years and have had no problems. The results are AMAZING! I spent a lot of time researching and sizing up different options and the end result was a great success. One of the most aggravating things during my journey was the lack of info and how scattered it was. I wanted to start a thread that had a lot of information for anyone who was interested in setting up brake cooling for their GD-Impreza. In addition to a step by step "How-To" with pictures of my own set up, others are free to share their own set up as well. The more information in this thread the better. I can link any and all posts that may be relevant or helpful in my first post so that information is easier to find. Hopefully this will become a "STICKY" so that information is even easier to access.

Anyway, without further adieu, here is my set up and how I did it.


First is the entry of the air into the front bumper. I used the OEM Fog covers as a clean and OEM looking brake duct. I modified them to accept a 3" High Temp Silicone flex hose, which was my size and hose of choice when performing this mod.

Heres how I modified the Fog Covers.

Parts/Tools needed.
OEM Fog covers
Sandpaper (320/400 Grit)
Dremel with cutting and grinding bits
Box Cutter / Razor Blades
Super Glue
JB Kwik Weld Epoxy
Aluminum Ducting Tape
Painters tape
Krylon Gray Primer
Krylon Flat Black/Semi Flat Black
Drill and Drill bits
Home Depot PVC (Thin walled) 4" to 3" Coupler/Reducer.

Image


This is how it looks after I trim it to fit flush against the odd shaped funnel in the OEM Fog cover.
Image

Image

Image

Image


I also sanded the back of the fog cover in addition to grinding a small grove at the exact contact point between the PVC coupler and the back of the fog cover. This allowed the modified edge of the PVC Coupler to sit in a channel and almost clip into place. This also provided more surface area and contact between the two so that the glue is more effective.

After the Super Glue
Image

Image


I then added JB Weld Epoxy to add some more strength and rigidity to the structure.

After the Epoxy
Image

Image


And I decided to be OCD and add more strength and rigidity by applying Aluminum Ducting Tape. This stuff is awesome.
Image

Image


After that I realized there was a sealed area that would trap water from the rain or car wash. So I drilled a few holes so that the water would drain out of the pocket. (these should have been drilled prior to gluing the coupler in place but I didnt realize it was necessary until after I had them glued, epoxied and taped down :) .)
Image

Image


This step is strictly for aesthetics. Lastly I taped up everything but what I wanted to be Black and primed and painted it.
Image

Image

Image

Image

Image

Image


The final step is a non reversible one that to me is not a problem but to others it may be. You will NOT be able to run OEM fogs after this modification is done to the bumper. On the OEM bumper there is a Rectangular "Tunnel" where the fog lights mount to behind the fog covers. That tunnel hinders the ability to install the covers after this extension has been added. So, In order for this to fit on the bumper you must do some CAREFUL trimming of the tunnel in the bumper. Here are a few pictures. FYI The only way to avoid doing this is to purchase some after market fog covers that have the extension molded into the piece and maybe they will be able to fit better without doing this.
Image

Image



This concludes the first Step in the Brake cooling set up.

Next was the hardest part to figure out due to the clearance issue on the inside of the subframe and engine compartment. The 3" high temp silicone flex hose would have to be routed through the bumper, into the engine bay(near the header and up pipe), and then into the wheel well, along side the axle and tie rods, where it would be routed to the hub or to be positioned to direct air at the back of the hub. (both of which are very effective)

Anyway. The solution was found when I stumbled upon a guy who makes the Roo Ducts. Randy Zimmer himself, the man, the LEGEND! I found his web page showing the progress of his invention that he was slowly working on and field testing. Well I decided to contact him and sure enough he was very helpful and sold me a set of his Carbon Fiber ducts that were a "God Send." His piece allowed for the hose to go through the bumper, by-pass the engine bay completely and enter the wheel well in the lower inner most corner where it mated to his piece. His ducts were shaped in such a way that they allowed clearance of the wheel at full lock and still had plenty of volume inside to move a significant amount of air. It protruded into the engine bay as much as possible with out having any issues what so ever. He also designed it to have 2-3 very solid mounting points to allow for a very rigid installation. The end result is as follows.

Here are the pieces off the car.
Image

Image


Fitted up by hand. (trimming of the inner fender liner is required and very easy.)
Image


Here is a picture showing the areas needed to be trimmed. Self tapping screws were used after a small pilot hole was drilled in the areas shown. You must first do a little test fitting and drilling of holes in the brake duct in order to line up the holes in the right spot. You also have to drill an access hole at the bottom of the duct to be able to install a screw on the inside back surface since that is the only way to mount the bottom of the duct. The hole can be covered with any tape but is not necessary since air will still move through it with no issues.

Image

Image

Image

Image



The last piece of the puzzle was easy to find and infact was the first thing I purchased and installed. The Backing plate which I purchased from Quantum Motorsports. These can be purchased from a number of different vendors and serve as a direct path to the center of the hub and brake rotor where the hottest point is. I personally did not want to just remove my OEM backing plate due the fear of the Lower Ball joint rubber Boot melting since it is so close to the rotor. I decided to custom cut the OEM Plate to allow for flush fitment of the Quantum piece. This way the piece was functional and my suspension parts were protected from excessive heat from the brakes.
here are some pictures
Image

Image

Image


I hope this was helpful. I can tell you that I have not experienced brake fade at the track at all, ever since I performed this mod. My brakes are very predictable and effective lap after lap on some of the hottest days.
 
#4 ·
In the end it really wasnt to expensive. I havent logged any specific totals but off the top of my head. The Hose was about 50 bux. I used under 8 feet. The Quantum pieces were about 75 bux. The Home Depot couplers were about 4 bux each. Glue and Epoxy was about 10 bux. The Roo Ducts were the most expensive part of the kit. Randy sold me a set that were his tester set and were an older design. He has since improved the fitment and structure of them. I dont know how much he sells them now but I picked these up from him for $250/pair. Im sure they are more expensive now.
 
#5 ·
I love the idea and this was what prompted me to take my own approach. Great work! :tup:
 
#8 ·
Thanks Guys. I hope this helps everyone who was searching for this kind of information just like I was in the past.

Good NEWS!!! Its already a STICKY!
 
#10 ·
No, The flex hose is very durable. I crushed it slightly into an Oval and just squeezed it under the Washer fluid tank. Its a tight fit but it works with no ill effects.
 
#11 ·
No, The flex hose is very durable. I crushed it slightly into an Oval and just squeezed it under the Washer fluid tank. Its a tight fit but it works with no ill effects.
This is NOT an option for the 2007. The tank sits almost flush with the back of the fog opening. I had to get an aftermarket tank to allow room for the hose. On the Passenger side, you have to pull the snorkus.
 
#12 ·
The "Tunnel" which you refer to as the fog opening, Ive cut out completely. I removed it and it give you a lot more room in front of the tank to allow for the hose to be routed into the bumper and down under the tank. As for the Passenger side snorkel. i totally forgot that was even there. I think that was the first mod i did. I dont remember how low it sat.
 
#17 · (Edited)
Boxtwo's Alternative Method

Goal
An inexpensive and REMOVABLE ducting system that will allow me to run brake ducts on track while retaining the ability to remove them when on the street.

The Platform
A 2007 STi that serves as a daily driver and TTB competitor.

The Obstacles
1. Snorkus on the Passenger's side
2. Washer Fluid tank on the Driver's side
3. Wide tires (wider than 245)
4. Aggressive Offset
5. Remembering to limit full LEFT or RIGHT steering wheel turns

The Parts
Duct Hose: 6' (<3' per side) Neoprene 500* #3621 from Pegasus.
Duct mount at hub: Quantum
Hose Clamps: 3" stainless steel. Keep extras
Cable Ties: Good ones, long 14" and short 4"


The Process

Car on stands, remove wheel on side you will be working. If you are unsure of how to do this or need instructions, please refer to the How To section.

1. Know the area in which you will be working. Almost all pics are from the RT side of the ar, simply because that is where I started.
Image



2. Remove the fender liner. A few pop-rivets and a #3 phillips up top.
Option 1: Replace all pop-rivets on the front (along the bumper) with cable ties to allow easy removal (This is the option I chose.)
Option 2: Re-use pop-rivets on the front

You are now faced with the snorkus...if you still have one. If you do, there are 1 or two nuts holding it in. Please refer to the How To section for more detailed instructions, but this MUST be removed for hose routing.
Image



3. A clear view of the back of the bumper, at the fog mount hole.
Image



4. Create the bumper adapter at the fog mount hole

This allows a couple of things:
1. The fog bezel/blank is completely independent of any ducting.
2. The PVC contraption can stay connected all the time (remove a hose clamp and remove the duct hose
3. It allows me to NOT cut out the "box" inside the bumper

All parts from Lowes
2x 2-1/2" SCH 40 Belled PVC Conduit (Electrical Department)
(We only need the "belled" part of this pipe)

2x 4x3" Flex Coupling (Plumbing Department)

2x 3x4x4" Downspout Adapter (Exterior Drainage/Outdoor Plumbing)

Total cost: 36.65

a. Connect 4" Flex coupling end to 4" end of Downspout adapter
b. Tighten hose clamp
c. Test-fit duct hose over BELLED end of PVC Conduit
d. Cut off extra PVC conduit
e. Insert uncut end of conduit into 3" Flex Coupling leaving about 2" exposed to attach to duct hose
f. Tighten hose clamp

NOTE:The following several pictures show the test-fit process and are included to show my methodology. Skip ahead to #7 to see the finished (un-trimmed) product.

4. Placement of Downspout adapter inside fog mount hole. It is TIGHT, but it WILL fit.
Image



5. Addition of Flex Coupling
Image



6. Addition of PVC Conduit (uncut)
Image



7. Pieced-together, untrimmed
Image



8. Test-fit of completed component.
Do not permenantly attach yet. You will need to make sure that the angle is correct so it will be directed to the inside, lowest corner possible.
Image



9. Angle checked and attached with two sheet-metal screws with larger washers.
Image



10. I used this corrugated drier vent tubing as a mockup for routing. It cost about $6 from Lowes and served to determine how much hose compression I would see at various wheel positions and hose placements. It is a throw-away piece.
Image



11. Remove Caliper, rotor, stone shield. Install Quantum ducts with supplied hardware. Be careful with the ABS sensor and wire.
Image



12. Mark and cut the fender liner. Using a scribe, the center of my hole is 3" above the lowest recess on the INSIDE of the liner, along the OUTSIDE edge of the rib. My hole diameter is 3.25".
Image



13. 3/8" wire loom to "soften" the edge of the fender liner

The hose is easily movable through the hole, removing the concern I had over binding there.
Image


DRIVER'S SIDE

14. Washer Fluid Bottle

A special THANKS to Vibrant Performance part #10400, 1.2L. There is a slick mounting plate that you can attach first and then slide the bottle onto it to lock in place. It comes with new fluid hose and a wire harness, which I will tap into my existing wire.

When looking at the STOCK pump, with the discharge to the LEFT, + is left, - is right. (Per the Service Manual, YB (Yellow/Black) is + and LgR (Lt Green/Red) is -. Fuse #15, BTW.)

This thing is SMALL. Approximately 7-3/8T x 5W x 4D.
Image



15. Mounting location, between radiator support and battery. This is only a temporary spot until I get a smaller battery and can find a permenant spot to mount it.
Image



16. My hose-holding method is half-assed, I will be the first to admit it, BUT, it does serve it's purpose. Use two long 14" cable ties and wrap the mount bracket for the ABS wire and the hose itself.

My plan is to fab a slightly better mount to avoid damage to the ABS wire, but have not gotten there yet.
Image
 
#18 ·
reserved
 
#19 ·
Very Nice! I love the way you modified the Fog Light Tunnel. Thats an excellent alternative to the fabrication I did to the Fog cover and tunnel. Nicely done.
 
#20 ·
Very Nice! I love the way you modified the Fog Light Tunnel. Thats an excellent alternative to the fabrication I did to the Fog cover and tunnel. Nicely done.
I know you said you wanted me to post, but once I did, I didn't want you to think I was trying to thread-jack. If you want me to create another thread, that is OK with me.
 
#21 ·
NEGATIVE!! I encourage people to post their set ups. The whole purpose of this thread and why it became a sticky so fast is the lack of info and how scattered it was before now. I want to help people find it easier and have more information about it. Thank you and great job.
 
#22 ·
Cool. I was glad to finally get it all compiled in one place!
 
#23 · (Edited)
wow this is a pretty cool set up and a great write up!. I might be doing this over the winter. It honestly looks pretty "simple" to do if you have a little bit of handy manism

Boxtwo: out of curiosity, why would you want to remove the brake ducts while on the street? Are there disadvantages or annoyances?
 
#24 ·
wow this is a pretty cool set up and a great write up!. I might be doing this over the winter. It honestly looks pretty "simple" to do if you have a little bit of handy manism
If you are referring to mine, it really isn't that hard to put the pieces together. The worst part was trying to find stuff that worked. It was funny though, as we were talking with the folks at Lowes, they were really interested in helping us find the parts to make it work. :lol:

Boxtwo: out of curiosity, why would you want to remove the brake ducts while on the street? Are there disadvantages or annoyances?
To return to street use, I pull the hoses and put the fog covers back on. Everything else stays in place. This was a feature that was important in my design. With the hoses in place, you have a dramatically limited ability to steer. This is OK on track, not so much on the street. With the setup I have now, I do not notice any disadvantages, other than not having a stone shield, but that is a HUGE "meh" to me.
 
#26 ·
I think with a FMIC it will depend on the routing of the tubing. The Vibrant washer fluid bottle is designed for folks with FMIC's that need the room where the stock bottle sits, so I am not sure. If someone with a FMIC could pull their fog cover and check clearance we might have a better idea to help out some others.
 
#28 ·
Well, I started to cook my Brembo's prior to ducting. Since the ducting, I have been runing DTC70 pads in the front and have noticed NO change in the caliper color (I used to notice it get darker over the course of a day.)

Plus, I have not noted any fade AND pads seem to last longer, although I have no quantitative data to support longevity. For tracking this car, the ducts have been the best modification, second only to camber plates/ASTs.
 
#29 ·
Basically what he said. Stock brembos can't handle the heat at the track. First track day I had with the this car proved that in the second lap of my 1st heat of the day. Since the brake cooling. Every track day is full of confident braking and faster lap times. Even street braking has improved. They are always crisp and bite very hard. For the sake of listing all benefits. Im pretty sure it helps extend the life of the hub bearings. I'm sure they get wicked hot as well. And since it always has cool air blowing on the entire hub it has to help keep temps down.
 
#30 ·
Welp, just got done putting in some ducts. Worked out pretty good...

I used boxtwo's idea of using the downspout adapter in the fog opening, then I found some very thin-walled 4" PVC pipe (I think its used for making landscape drain systems, because they had a version that was perforated) that fit the downspout adapter AND also happened to perfectly fit the inlet of the Z06 ducts that I bought.

I had to cut about 1" out of the Z06 ducts about 6" in from the inlet. This allowed me to shorten the ducts (duh) and also rotate the inlet around so that it would straight on at the downspout adapter. Once I got the angle correct, I spliced the peices back together using the same 4" PVC pipe, that just happened to fit perfectly around the spliced area.

Then I used some PVC shower drain pieces and cut off the grate bit to get a piece of PVC that's about 2" long and has an OD of just shy of 3". The shower drain was the only thing I could find with the OD necessary, since most PVC fittings are made to go on the outside of the pipe, not the inside. I attached these to the outlet from the Z06 ducts. Then all that's left was to run the hose from the ducts to the Quantum Motorsports piece on the brakes.

If anyone's interested, I'll try to get some pictures later (I would've done so while I was working on it, but it was late and I wanted to make sure I had it done in time for my trackday this weekend)

In the end, I needed less than 3' of the high-temp silicone hose (which is nice, since that stuff is pretty expensive for what it is) and I can still turn the wheel all the way to lock with just enough clearance for the Z06 ducts.

Thanks for all the ideas guys!