How effective are the stock ducts? I actually removed mine, they only seemed to funnel air to the front of the tire. Plus I don't do track time or auto-x.

Err well not the rotor itself. I was thinking of the metal guard thing that goes behind the rotor. I found a writeup somewhere too once.



http://www.3000gtvr4.com/pages/ramair.html



At least its an idea. I was gonna go looking around and see if i could find some space in my front air dam too.

If you'll notice, the brake rotor dust guard has a bend outward in the front - this is to 'scoop' air into disc vanes that run the circumference of the rotor. brake ducts are designed to aide this action be creating a path for fresh air to travel from. as opposed to a sealed fenderwell, which may have stagnate air at lower speeds.

The stock ducts are not excellent, but don't hurt to have. Personally, I believe that air would be better used directed into a cold air box.



As for making your own, it is not as easy as putting a tube in there. If the car is street driven, then the piping has to be small enough so as to avoid being rubbed when the tire is at full lock (this isn't a problem on race cars since they are almost never at such extreme steering angles). The design of the ducting is crucial also. Air needs to be directed at the center of the rotor since vented rotors are designed to push air outward from their center. This duct should also be virtually sealed to the rotor (not sealed, but very close and has to withstand some vibrations).



The gains you'll see from putting in ducting is questionable. As I've religiously stated before (and will continue to do), the stock TII brakes are pretty outstanding with better pads and lines. Unless it is a track car (read: track, not autocross), it is unlikely you're reaching temps where the ducts would help. Autocross is (relatively) slow and quick, giving the brakes ample time to cool down between runs. Hell, a racing pad doesn't even have time to really heat up during runs so I doubt the rotors are overheating.



As for the cool factor, well, if it's done really well it could be pretty cool. But then you have to think of whether it's worth it, which in my opinion it's not. You'd be better to buy some slotted rotors to look cool (that's a whole nother can of worms there).



I wouldn't, and don't, bother.



Redwood

i had heard that the openings in the lip on the R models was ducted to the front brakes....is this true? i really dont know. just thought it sounded like a good time to find out

In Autox I have difficulty getting my pads up to temp so that they are sticky.



If your doing open track days its worth looking into other wise I think its not worth bothering with. The inportant part is doing it right.



Just make sure you bleed your brakes and have good pads like Hawks in there you'll be fine for Autocross.

for what its worth we run stock brakes (pads too) on the race car (na fc) and its fine. we could perhaps benifit from ducts and slightly more aggressive pads, but thats like 10ths of a second....