Matthew91-Z28

I saw this a while back when researching C4 brake upgrades. This is a picture of how C4's run cool air to their fronts...never realized that those little screens on the rear GFX of C5's were really ducting for the rear brakes.

ANyway.....it would not be tough at all to steal some air from behind the fog's and route it to the wheel wells in a 3rd gen....there are prob many ways to do this.

At any rate, it could be the poor man's means of decreasing brake fade. Crap, it would help with any brake setup. Here is a pic....

Matthew91-Z28

Here is another tidbit::

"Instead of blowing air aimlessly around the wheel well, these brake ducts finish where GM left off. Air is blown directly into the hub/rotor area to dramatically reduce rotor temperature. Works with up to 10" wide 18" tall front rims. These are now standard equipment on our C500/RSR.
We recommend using these in combination with our Stainless Steel Braided Brake Lines and Stainless Steel Pistons for the ultimate in repetitive and high speed stopping performance with stock GM calipers"

RMK

This is something I've been thinking about for a while now. From what I can gather you either get it from the front like you said or install a couple of NACA ducts.

Robert

Matthew91-Z28

Yeah..it seems like a sound idea....I have not heard of anyone here doing this...although they may have and never posted it. What are NACA ducts?

C4's have that open wheel well...not tough at all to duct to those calipers....But, 3rd gens might be tricky. I don't know about the wheel well design (i.e how much of that plastic has metal behind it). Would be fairly simple to run rubber hose from the front, under the chassis, and up along inside the wheel well, but would there be any rubbing problems?

Guess you could cut a 3 in hole into each wheel well if you need to, but would that cause any loss in structural rigidity?

I have tomorrow AM pegged to replace my calipers w/ rebuilt ones. I'll get a closer look and see what it looks like.

MrDude_1

ever see thoes lil triangle ducts that take air from a side panel and channel it in? thats them


think vents on a F40.... or on the side of some aircraft, or like the ones in the side glass of NASCAR cars....

Matthew91-Z28

Never mind about the wheel well issue....I just looked at mine. Sometimes I need to remind myself. Thats the easy part...now just got to figure out where to take air from. Would be ideal to cut out a passage in the front GFX and run it from there. Hate to do that though without a really good design to funnel the air into a hose. Looks like its time to go to Home Depot.


Could run it from behind the grille openings.....wondering though how easy that would be.

RMK

Here's a pic

RMK

That is the way I was thinking of doing it.

Matthew91-Z28

that funnel looks about 6 in wide and 10 in long. Wonder if you could cut a similar chape in your GFX, slide that one thru, and connect your hose behind it?


Or could fab up a rectangular design that ended in a tube, like the vette one, and keep in flush w/ the gfx

Matthew91-Z28

pic of what I mean

Matt87GTA

One thing to keep in mind is that you really want to have the air come into the center of the rotor and push air out through the vanes of the rotor. Ideally you want the duct to almost seal off the inner hub area of the backside of the rotor so air has to come through the duct and flow through the vents of the rotor.

If you just route some ducting to have the air blow onto the inner rotor surface it will do an alright job of cooling the brakes but it can cause problems with over-cooling the inner surface as opposed to the outer surface of the rotor and they will tend to crack.... This is probably only a problem if you really push your brakes and have aggressive enough pads.... But running brake ducts in the first place means those conditions already exist, so.... .

MrDude_1

yup..

the only ones ive seen in real life were open wheel race cars... most of them use carbon fiber scoop assemblys that move with the spindle and grab air from the inside edge of the tire...

z28cdoyle

It is possible to put brake ducts on our cars. I have had them on my car for a few years. I run two 3" hoses to each front rotor. I run my car at road race tracks. I have the stock 4 wheel discs, racing tires, and about 330hp so getting slowed down is a real prblem at the end of straightaways. I will be upgrading to LS1 brakes this winter though since I have taken the stock brakes about as far as they can go and it is still not enough.

There are some problems you will face though:
-The biggest problem is getting the hoses to the inside of the rotor. As someone else mentioned, the object is to blow air to the hub so it flows thru the vanes. You can route hoses to the inside of the rotor easily enough when the wheels are pointed straight and the suspension is not moving. However, hoses get rubbed by the front tires when you turn the steering wheel. Suspension travel also causes the hoses to flex a lot so they will not stay in position inside the rotors. In parking lots and driveways, don't turn the steering wheel more than about 75% of it's travel or your hoses will be crushed. I have tried to make a manifold to seal the hoses to the center of the rotor like Winston Cup and road race cars have but I have never been able to come up with anything that will work. I just have my hoses pointing at the center of the rotor.

-Our spindles have no where to attach hoses so they stay pointed to the inside of the rotor. Lots of plastic cable ties is what I use to keep them in position as best as I can.

-Road debris, rain, bugs, etc blows thru the hoses and gets blown into your rotors. To really get air to the rotors, you'll have to remove the debris shields bolted to the spindle covering the inside surface of the rotor. This allows lots of air to the rotor but also lots of debris.

-Where do you collect air? You could cut a hole in the nosepiece or put ducts behind the fog lights. I built a panel and attached it to the ends of the air dam that scoops air into the radiator. Then I put my ducts there. I saw this on a TransAm road race car, but it did not get anough air to the brakes and I incinerated a set of rotors at the track. I have my hoses running to the openings where the turn signals used to be and collect air from there. It works really well. If you drive on the street though, this will not be an option.

On the plus side, it is surprising how cheap this can be done. I would forget the expensive brake duct hoses you see in race car supply catalogs. I tried that stuff and in one day at the track it was destroyed from the tires rubbing it. I use aluminum dryer duct hose instead. It costs about 1/4 as much as the racing brake duct hose and is more flexible. When the hose gets crushed/rubbed thru from the tires, you simply replace it.

Here's a cheap tip to attach the hoses to the spindle; a soup can. If you use cable ties or wire to hold the hoses to the spindle, the movement of the suspension/steering will rip up the end of hoses and they'll fall off. A soup can fits perfectly in the end of 3" duct hose. Cut it so it is a few inches long, clamp the hose to the can with a hose clamp, then punch holes on the metal can for the wire/cable ties to the spindle. Much more durable, and costs almost nothing.

Oh, and it is really cool when friends look at your front wheels and see brake ducts.

I can't offer any photos of my setup since I don't have a digital camera.

Have fun fabricating!

Matthew91-Z28

Thanks for the info/....I've been tossing this around over the weekend trying to figure out a plan of action. You supplied some great information. I plan on cutting two 3-in holes in my lower spoiler, one hole close to each corner and then fabricating the rest.

I guess the first question should be, is it worth it?? The parts cost next to nothing for this mod; is this worth the effort and cutting two holes in my lower spoiler?

19doug90

my solution....remove the turn signals and run ducting from there i plan to do that this winter. I am also going to fab up replacement turn signals its all planned out....just gotta make it happen and get some pics for you guys!

z28cdoyle

Mathew91-Z28,
Is it worth it? To me this depends on the use of your car. For me it is worth it since without the ducts I cannot get my car stopped on the track. The ducts reduce temperatures of the pads/rotors and reduce the fade that I get during a session on the track. On the heaviest braking track I run, the ducts have more than doubled my my pad and rotor life. Without the ducts I would use up a set of brake pads and rotors in one day or about 125 miles. The temperatures were so high that the caliper dust boots burn off and crumble. The heat destroys the rotor as well by causing hundreds of stresss cracks on the rotor face. These are so wide you can actually catch your fingernail in them.

I don't drive my car on the street very much. When I do though, I don't use the brake ducts. I find that I just don't need them.

If you have any of the problems I mentioned, the ducts will certainly help. If you are unhappy with the stopping distance of your car even when the brakes are cold, then the ducts will not help you. For that upgrade to a better system or change pads. Until I switched to racing brake pads I had no idea what a difference they make over normal street pads.