jpobrien

I've been trying to figure out what to do about front brake cooling on my C4. Currently, I have the Madvet airdam with plastic inlets and ducts (2" or 2.5") that I have fastened to the lower control arm on each side, hopefully blowing some air behind the wheel to the rotor.

DRM brake ducts? Spindle ducts? Hose routing?

There's not a lot of room in there.

What have some of you done to make it work? I continue to have a horrible time keeping brake pads from melting off.

Thanks for any input.

CF6873

I fabricated my own duct system when I had my 94. I used dual 2" hoses on each side. It worked great and I had no fade with XP10's.
I sold them to a forum member this past winter.

http://i57.photobucket.com/albums/g2...00_0009_00.jpg

http://i57.photobucket.com/albums/g2...3/100_1277.jpg

http://i57.photobucket.com/albums/g2...3/100_1276.jpg

jpobrien

That's a nice looking setup.

Doesn't look like it'd be that hard to make ... if you know how to weld, which I don't - yet. I need to figure that out this winter.

CF6873

No welding was necessary. I used epoxy and rivets to join the downspout material with 2" exhaust tubing. I can weld but I can't weld steel to aluminum.

jpobrien

I guess I didn't look close enough at the pics.

Looks like something I should consider for mine.

Sidney004

Here is another useful thread on cooling ducts:
http://forums.corvetteforum.com/show...c4+brake+ducts
Due to the tight confines, 2" hose is the max. I bought my spindle ducts thru CF member ZR1 MK. Routing a hose to the rotors without a spindle duct is worthless; the only thing you will achieve is a melted hose. Other mods that I have done are SS pistons from DRM and the mandatory Motul 600 fluid. You didn't mention which pads you are using, but anything less than full race will melt. From a maintenance side on these marginal J55's(you are using J55's right!) speedbleeders are a good idea to ensure that you always have fresh fluid and well bled brakes, also routinely measure the calipers to ensure that they have not spread. I have found that the calipers spread about 2-3 mm within 6-8 events and need to be replaced. I buy used non raced calipers on Ebay for about $15-$20 apiece(I used seasoned rotors as well, equally cheap.)

jpobrien

Thanks for the thread link - lots of good info there!

This year I bought the C5 front brake upgrade kit from VB&P. I'm really not happy with it though. Pad taper is horrible.

Also, I have titanium heat sheilds and I use ATE Super Blue fluid. I bleed them after every few sessions.

I hate to do it, but I might have to upgrade to the LG Wilwood setup for the front.

No matter what I do with that, I need to make sure to get as much cooling in there as possible.

Oh ... pads. I currenly use Carbotech XP12s on the front, although I just ordered a set of PFC01s for this weekend. We'll see if they last any longer than the Cts.

Sidney004

It does look like you are doing almost all you can other than the Wilwood upgrade. Is the pad taper radial or longitudinal? If it is radial, it may be a result of the caliper having spread, which will cause a long pedal, increased wear and heat at the top edge of the pad and resultant failure.

jpobrien

The taper is longitudinal.

Last weekend, I switched the pads side-to-side after the first day to even out the pad wear. The problem is that it took several pumps of the brakes going into each turn to have any stopping power. Eventually, it evened out.

SDF

I went down the same road you are a few months back. I started by replacing the front calipers with Grand Sport calipers purchased from DRM. In those calipers were placed stainless pistons.
I also purchased from fellow Forum member ZR-1 Mike some spindle ducts which will accept 3" hose. He did a fine job with these ducts and was great to deal with. After alot of searching, I had Quantum Motorsports make me some air inlets from some drawings I sent them. The inlet is small enough that it can be incorporated in the front spoiler. The opening is wide and narrow and leads into a 3" outlet. I am still deciding the best way to route the hose. As others have said, there isn't much room to work with. I know that the air inlets I spoke of earlier have been placed in Quantums catalog. If I can help any further, let me know.
On a side note, I had purchased from a "Corvette Vendor" their front spoiler with the cooling ducts incorporated. It was nothing but junk and I returned it immediately.


Scott

Sidney004

Scott:
I found the 3" hose tricky to deal with. The wheel would pinch the hose near full lock. I think if you remove the panels protecting the engine bay from road debris, you can get a "straight" parallel attachment of the 3" hose without having it pinch the wheel while turning, otherwise
2" hose is the way to make it work. The spindle ducts even with the 2" hose was a major improvement in longevity.

SDF

Sid,
Thanks for the reply, I'll take a look.
Scott

astock165

Brake cooling on a C4 is a tough one. I tried the Mid America kit and thought it was junk so I ended up making my own.

I took the outside pieces of the bottom skirt off and made up some inlets w/ PVC pieces from Home Depot


Here is the left side mounted on the car:




I ran two 2" hoses as shown here, very similar to what CF6873 did.


I ended up chewing up the 2" hoses and had to bring it down to 1". It's not optimal but I figure something is better than nothing. With the 1" hoses I have them both pointed to the inside hat of the rotor.

I'd recommend routing them between the sway bar, tie rod and lower CA. Reinforce the areas that will rub with sheet metal.

ScaryFast

Quick question - are you sure you're overheating the brakes? Buy some high temp paint (summit has it, I think it's like $6) that changes color over temps and see if you're exceeding your pad and rotor capability before spending too much money.

I know that in general the C4 brakes are woefully inadequate, but there could be other factors contributing to brake fade such as fluid, pad choice, front / rear bias, pad tapering, etc.

Ducts certainly won't hurt you, but they may not solve your problems.

I had fade for a long time in my big-brake kit and assumed it was temp related. Thorough investigation revealed that it was due to slop between the hat and rotor assembly. Fixing the hat and rotor firmly together solved it and the brakes have never been better...except that I have some rear lockup.

Aardwolf

I have the madvet ducts as well (needed a new spoiler) and they are doing well. It's 2.5" IIRC and the hose is plastic. This last weekend I had a track event and tried painting the end of the hose with high temp paint. The hose melted less. I would like to test this more though. I have mine routed to the bottom:



and



I put a thin hard piece of plastic in joining the sections together so the front part is less likely to bend back at high speed, that is the two bolt heads in the spoiler:



Does anyone know if that white part above the center spoiler needs to be there?

I ran Carbo xp8 and the brakes were awesome at Road America.

BrianCunningham

Here's the kit Mid-America sells installed on a friends car


The tubing is kinda cheap, and your on your own for mounting it on the upright.

I like what the forum members have come up with better.

anyone done a splitter to help pump the air in?

Solo2GS

I as well have teh madvet front air damn on my GS, but instead got some high temp tubing that does not melt and ran it like a few others have directly to the back of the rotor. In the binding areas I wrapped the tubing with some material that would not cut or tear to protect it.

RAFTeRACER

I purchased this setup and it would have been great on the track but I did not think ahead and autocrossed the car. The downspout ducts were none too happy when I started drilling pylons! I just recieved my Mid-America setup for this weekend. Hopefully I can keep from breaking them before the credit card bill comes.

CF6873

Sorry to hear that they didn't hold up. I can't say I ran over any cones when I had them on but I did ding one up once and straigtened it back out. Good Luck on your new setup.

Kinkajou

There was a TV show on how Vettes are built. I do not remember the name of the host .
Anyway, they where explaining some of the faults that the C6 had and what GM did to correct it.
They explained that aereodinamics where good but the front end was a little bit light under speed. Another problem was that the brakes would become hot after some laps.

So they came up with a very interesting solution. Under the front end there is a high pressure zone, so they produced a flat piece of plastic with a hole in the center.
The hole was conected to a hose that was directed to the brakes.

When the car was going fast, this plastic piece produced inverse lift because of the design, and because there was so much air pressure the air was directed to the brakes. Solved the two problems with one solution.

I am working on making a carbon fiber part like this for the C4, maybe it will work nicely.

Could someone with a C6 post some pictures of the undeparts of the nose of the car please?

What do you think of this guys?