View Full Version : Where are your brake ducts?

06-25-2002, 09:04 PM
I read this site a bunch, but don't usually post. I'm building a '94 DX hatch for ITA and I cooked a set of R4 pads on my first shakedown track day last Friday. I've been looking into brake duct options, but I'm unclear on the rule for poking holes, or where to have the inlets.

The car has areas for factory fog lights, but I don't think I can cut these out (correct me if I'm wrong). I can tie a plastic inlet "behind" the center grill, but can I cut it at all to facilitate mounting?

06-25-2002, 11:56 PM
Hi John, I think you can cut where the fog lights are supposed to go. The rules state a 3 inch diameter hole in the front is OK. Let me know when you are done. I'd like to see the pics.


06-26-2002, 02:53 AM
Check out Tom Fowler ARRC winning CRX. The rule is such that you can cut open the fog light opening but the duct to the brakes can only three inches. If you want you can simply make a three inch hole in the valance. There is more to this than making a hole and duct work.
If you just make a hole, the air will just spill by the hole and not cool at all. You need some sort of deflector at the outside edge to cause the air to go into the hole.

06-26-2002, 05:45 PM
I looked at the car last night (since it's on jackstands anyway) trying to figure where I could run 3" hose. The drivers side looks like a no-brainer, but the radiator and support are in the way on the passenger side. Even cutting through the foglight holes may not be an option due to the air filter and washer bottle location.


I'm looking at mounting one of these things behind the main grill opening, and running 3" ducts off of it to each wheel. I'll see about getting pictures when I'm done, but so far, this seems like the best option for this car. I'll keep you posted Greg.

07-08-2002, 05:03 PM
Well, as a follow-up, this is what I came up with. I'll probably replace a few of the zip ties with wire before my second shakedown session this Friday.






1994 Civic DX - ITA #93

07-08-2002, 08:34 PM
Thanks John! I am going to copy your set up.

07-08-2002, 08:45 PM
You all might want to think about actual metal band clamps and brackets rather than tie wraps, once you get things routed to your liking. Those bad boys are down there in curb-whacking land and when those ducts fall off and start to unwind, they can trail 50 feet of wire behind your car - leading to a black flag.

You should team up with a couple of other racers and buy a roll of real aluminum duct tape, too - the stuff with the peel-off backing. It makes connections really tight and pretty, if you clean things up really well before putting it on.

Looks pretty good, John! Someday, someone out there will come up with a hub-end duct assembly that bolts to Honda uprights and points the air right where it needs to go. Until then, there is no real way to finish that end, short of a bazillion hours of labor and a well-stocked sheetmetal shop...


07-08-2002, 08:55 PM
Seems like from the pics youre doing a great job at cooling the cv joint....

anyway, i already removed my front rotor shields, but anyone think it would be better to drill the appropriate sized holes in the rotor shield and added a nipple to accomodate the duct for better direct feeding of cool air to the rotor?

07-08-2002, 08:56 PM
Nice work, John, but the best part of your car is still the color!


07-08-2002, 11:27 PM
Ah, forget the brake ducts. Just bolt on a set of 13" rotors and 4 piston calipers. No one would notice....... http://Forums.ImprovedTouring.com/it/wink.gif

07-09-2002, 01:48 AM
Good idea on the clamps. I have access to metal tape by the bucketload, and a sheetmetal shop to boot. While I was lying there on my back last night looking up at the attachment to the lower fork, I was trying to visualize a thin bracket to attach to the caliper bolts and/or shock fork bolts. There's gotta be a better way. I think I'll work on something this year.

I completely toasted a brand new set of Brembo blanks and R4 pads during my first track day with the car a few weeks ago. I need more air to the brakes and this is simply my first effort. I have another track day this Friday, and will compare temps to the last session. The weather forecast calls for very similar (warm) conditions.

1994 Civic DX - ITA #93

Greg Gauper
07-09-2002, 10:33 AM
I couldn't tell from the photo (the shock was blocking the view).

Do you have your brake line anchored somehow at the shock? Typically the stock mount is too big since it's designed for the larger OEM hose. Make sure you have a ty-wrap or something to keep the brake line from sliding thru the clamp and rubbing against the inside of the wheel. It can get pretty exciting if your brake line gets cut (been there, done that!)

You indicated that you 'toasted' a set of rotors. By this do you mean they got scored up or glazed over? If they are just glazed over, you can sometimes salvage them by bead blasting the surface.

Way back when (in the good ol' days before Hawks & PFC's) I used to have a problem with Rebco Metal Masters causing my rotors to score pretty badly. I solved the problem by filing a small (1/16 to 1/8") groove in the brake pad similar to that found on the OEM pads. This groove acts as a 'degassing' slot to prevent the hot gas or super heated air from getting trapped between the pad and the rotor. This hot gas can act like hot plasma and contribute to rotor scoring. My rotor scoring was significantly reduced with this little trick.

07-09-2002, 12:46 PM
Originally posted by Tyson:
anyone think it would be better to drill the appropriate sized holes in the rotor shield and added a nipple to accomodate the duct for better direct feeding of cool air to the rotor?

I saw the same thing before and I am contemplating just cutting a hole. What is the down side to removing the splash guard?


07-09-2002, 01:23 PM
The rotors are grooved pretty deep. It's sorta hard to see in this picture. This is a shot of the R4 pads also.
My brake lines are tied to the lower shock body. I'll look into what you described. Thanks.


1994 Civic DX - ITA #93

Greg Gauper
07-09-2002, 02:41 PM
The pads certainly have the grooves in them that I was refering to. Next question - did you go out on brand new rotors & pads? You will get several opinions from various people regarding this. Here is mine - even if the pads are pre-burnished, the pads and rootrs are not perfectly smooth. These small imperfections can cause isolated 'hot spots' between the pads and the rotors which can lead to scoring like you experienced here. If you have a means to do it, you should try and break-in (no pun intended) the pad and rotor combination before you start to use your brakes to their fullest. This can be done in one of two ways:
1) Put the pads & rotors on a street car, find a deserted highway, and make several stops from speed getting the pads hot enough so you can smell them, then drive around to cool them off.
2) On the track, use the first two or three laps to do the same thing, then drive one or two laps as easy as possible without using the brakes.

You might want to experiment with a different (rotor friendly) pad material like Hawk Blacks. I run Hawk Blues and while they don't score the rotors like in your picture, they do wear them out after several races. Blacks are supposed to be softer than Blues.

Last - your rotors look similar to how my rotors on my old CRX used to look when I ran Showroom Stock in the good old days of OEM brake pads.

You might be suprised at what you will see if you bead blast the rotors or lacking access to a sandblaster, use some 100-150 grit emorry cloth and a lot of elbow grease. Don't use a sanding disk as this will remove too much material and leave and uneven surface. Use a hand sanding block and change the cloth frequently. The scoring may not be as deep as it looks. The grooves might be pad material that has 'picked-up' and deposited itself on the rotors. I was always amazed at how much material I picked up on the rotors and how good they looked after sanding.

BTW - What track did you run at that caused this?

[This message has been edited by Greg Gauper (edited July 09, 2002).]

07-09-2002, 06:14 PM
The rotors were brand new Brembo blanks, and I had one track day and 2 autocrosses on the pads last season. I have Hawk Blue's on the way and they should be here before my next track day this Friday. The track was Bremerton Raceway just outside Seattle.

T1 at the end of the main straight, you (I) slow from about 105mph to a mid second gear lefthander. At the top of the track, leading back onto the main straight, is a slow hairpin left - maybe 80-90mph to 25mph in a hurry. Otherwise, it's a short track on a old airport runway. Fast lap times for me were 1.07.xx.

1994 Civic DX - ITA #93