Nader Fotouhi

Car is a stock class 993 weighing 3100 lbs+ with driver. It seems that after 5-7 laps in 70-80F day, my brakes loose their bite and the car/driver need more distance to slow down. I contribute this to heat buildup. I have been using my stash of Pagid orange for DE/testing, saving my pagid blacks for if I ever go racing again (always next race).

What is a good way to cool the brakes on a 993? If not a cure for my distance problem, it should at least help preserve my rotors for a day or two more.

shizzle

Have you thought about installing brake ducts on your 993, like the following http://www.gettydesign.com/993_misc.html#brake? Also, what brake fluid are you using?

ninjabones

I never had brake overheating issues in my 993 when back in stock G (including 90 min endures in 90+ heat). I was consistently faster with pagid blacks (better bite), but they are harder on the rotors and I experienced more problems with ABS interference. I preferred the yellows, which were much easier on the rotors, lasted much longer (justifying the higher cost), less likely to create ABS issues, but my lap times were a bit slower. I didn't even use SRF back then (just ATE super blue). Ducts can be helpful; with a stock front bumper, your best option is to use brake ducts, and route the 3" ducting through the channel in the unibody

JoeMag

Regarding temps, let data tell ya what's going on. Have you tried using this?

http://www.racerpartswholesale.com/p...Fa5DMgodWhwA-w

Nader Fotouhi

^^
I have brake duct on the front similar to what Glen shows. I also have the 3" hose going to the rotor, but it is real work to get them to the ducts in the front, so they are just hanging behind the bumper cover. Besides, the hoses get torn quickly due to being hit by the tires, so I am not sure how effective they are. I'd also like the fact the duct get clean air to my oil coolers.

I am going to instal the stock scoops. I also saw a Cayman on the lift where scoops were used under the car to get air to the rotors. I am wondering if something like that might work.

SoClose

As Glen suggests, cut holes in the tub to channel air thru, and blow directly onto the inside of the rotors. Don't see that his pictures adequately show this and unfortunately our 993 is far from us. This was the definitive fix for us.

Matt Romanowski

If you just have the hoses behind the bumper, you might be doing more harm that good with the ducts on the rotor not doing anything. Run them to the bumper and get some air in there and the problems will probably go away.

Didn't some 993 variant have a "scoop" that went on the front of the A arms?

ninjabones

This photo kinda shows where the ducts emerge from the channel in the tub on the inner wheel well. If you try to route the hoes externally, they will kink, rub on the tire, and you will get very little air flow as mentioned above.

Frank 993 C4S

993 brakes are usually fairly bullet proof. Before you do anything major, I would first check whether you really have a cooling problem or not by using a good brake fluid and bleeding the brakes between events. I would also recommend the Pagid yellows which last long and are easy on rotors. Have a look at the way you brake and whether you are over-braking. A coach can help you with that.

The 964RS had a scoop on the front A arms. Here is an articule by someone that has done it to the 993. It's a cheap first step:

Brake Scoops

certz

+1 to the brake ducting throught the tub and brake fluid (I am also Stock G). I had the ducting done by Midwest Eurosport in Chicago (not sure where you are located). I was running Motul RBF 600, which is good, but I recently switched to SRF - I still think SRF is overpriced but wow is there a noticeble difference. I also switched from Pagid Yellows to PFC 08's, which I like better, but the yellows are good also.

Nader Fotouhi

Glen,

Is this also how Bob T has his? He was telling me about it.

Flying Finn

Here's a DIY I wrote few years ago: http://p-car.com/diy/coolingduct/

Works well, I always used to have overheating issues but with the ducts, didn't.

ninjabones

yes, bob's emerge from the inner wheel well much the same as mine. However, he has an EVO I front bumper, so he routed from the scoops down low on the central bumper, into the trunk, and then into the unibody channel. This is somewhat more complicated as it requires moving the ABS pump, and you have to cut huge holes in the front trunk. however, it is a much straighter path for better airflow.

Yonker has NACA ducts cut into the trunk-lid, and the path is even straighter and doesn't require moving the ABS pump. But he has an entire clamshell up front, and that would be a PITA to disconnect every time you open up the front trunk.

With the stock bumper and the EVO II bumper, you can do what I have shown in the photos above.

bobt993

Glen,

I did not have to move the ABS pump on mine, but the ABS ECU did have to move. (relatively easy). Nader there is a couple things going on with your setup that are causing issues. I did feel driving your car that the brakes need some attention.

Bill Verburg

Here's another very efficient way to do it