Ok, this idea hit me a few weeks ago and I decided to go with it. I wanted to incorporate brake ducts for track day, but didn't want to cut the fake vents out of my bumper. The fact that I had an 05 style bumper made it harder as well. Also adding to the challenges was my CAI which was directly behind the right vent and would prevent any ducting on that side. Step in NACA laminar air ducts:



They're made to pull in air from flat surfaces as you go by and often mounted on the side of the car. I figured I had just enough room inside my bumper to mount these on the underside of the car facing downward. There's alot of airflow down there and I wouldn't have to cut my bumper at all. First, I started off with the following supplies:



2-NACA ducts
Enough 3" air ducting to do both sides
3" Aluminum flanges
4-screw clamps
(jb weld in picture not used)


First, I started off by removing the wheels, caliper assembly and rotor off the axle. Be sure to support the caliper on a box or something so it does not hang. I used a bucket.



Then, using a 3" hole saw I cut through the dust shield in an area that would be easy to access. I temporarily removed the ABS sensor to prevent from damaging it with the hole saw.



Then, I test fitted the aluminum flange on the inside of the dust shield, marked the areas that needed to be trimmed and installed it onto the dust shield.



After making sure the fit was flush with the surface, I rivetted it so it's secure.



Next, I cut the NACA ducts so that they were squared off and cut the holes out on the connection side as they are solid when you buy them and not really straight edged.



I also made a template out of foam board for an opening that they can fit through. I used this later to stencil the actual hole in the under lining.



I then removed the inner wheel well lining completely by taking off two screws and a bunch of clips. It's fairly easy, but finding all the clips may take a while. After looking at the room I had and the obstacles I had to avoid (i.e. water pump), I used the stencil to cut a hole for the ducts on the outside edge of the part of the lining that's under the bumper.





Then, with a few pilot holes, I attached the ducts to the underside with a few screws.



Paying attention to where the cross beams and supports were in the front of the car, I cut a hole for the ducting as far back as I could.



And then passed the ducting through the hole and attached it to the duct.



Then, I carefully reinstalled the wheel well lining and attached the other half of the hose to aluminum flange allowing enough slack so that the wheel can turn fully from left to right. I secured the ducting to the flange with the clamp and with zip ties to the upper A-arm.





And, we're done. All that's left is reattaching the rotor and remounting the wheel. I'll be testing them out on the track this weekend and will do temperature test with them open and closed and post once I have the results. Overall, I'm very pleased with the installation. It went together very easily and it seems to be a viable alternative to the traditional brake duct style.

 

very nice. great sloultion to cutting and for those with CAI

 

The wheels are definitely going to rub on the ducting. At least, they would with stock 16-inch wheels. I don't know about the 17s or whatever you may be running.

Instead of running the ducting along the front of the upper A-arm, you probably need to sort of tuck it under the arm.

 

The clearances seemed to be fine. I followed the routing instruction from other install threads and this should allow for enough room at the entry point of the hose from the lining. As for the A-arm attachment, I'm running 17" wheels with the 05 so I didn't bother tucking the ducts under the A-arms, but if I need to, it's a quick fix.

BTW, the pictures are kind of misleading. The hose is about 1/4 of the way under the A-arm and not directly in front. It's easy to twist them to a lower position though.

 

Great job. But here is my question. Our wheels are open enough to provide plenty of cooling air to the rotor. Wonder whether this would provide any performance increase?

If someone is really concerned about brake performance of our car, they should be checking pads, brake lines and brake fluids. That along should be enough to achieve ideal braking performance.

 

[QUOTE=soundzero,Jul 10 2005, 07:19 PM] Great job.

 

That is great. 100F makes a fair difference thats for sure.

 

I am definitely no expert at braking systems, but it seems to me that you are ducting the air incorrectly.

I believe the ducting should guide the cool air into the vents IN-BETWEEN the inner and outer rotor surfaces. That would provide equal cooling to both surfaces of the rotor.

If you are cooling one surface (the inner) more than the other, there may be increased risk of warping/cracking the rotor, and uneven wear of the pads due to temperature differences.

-Pete

 

Track use generates a great deal of heat and many of us have seen a substantial improvement by using ducts.

The inside center of the rotor is open venting to the center so this nice installation will cool properly.

Nice job! Hope you can show that the NACA ducts on the underside do a good job.. sure looks like you have a winner.

 

An ideal setup would probably involve making a housing that distrubes the air on both sides of the rotor. However, that would involve molding and more money that I care to spend for this project. Perhaps if I was a dedicated racer, I would have invested more.

This style is being used by most of the race guys that have brake ducts. So far, nobody has reported warping or any adverse affects to having the vent empty out on only one side. While it is not the perfect design, it is a working design.