ast2000

I want to add cooling ducts to the front rotors. Do I need to remove the backing(?) plate to make this effective and where should I aim the outlets, front of rotors, or at the calipers?

Gary Church

Take a lead from the Porsche Cup Cars. No backing plate and air to rotors.

Adam Richman

From everything I have read or heard, you want to duct air into the hats. Any air you blow at the rotors themselves gets pushed off by centripital (?) force. I have never heard of anyone ducting air to the calipers but since they - it would seem - are an effect not a cause, I'd go for the hats.

Bill Gregory

As Gary said, remove the backing plates, and you want to pipe in air to the rotor. If you have a 911 or 944, OG Racing makes a "cool brake" kit with a scoop that goes under the a-arm (911) with a short hose into a part that replaces the backing plate which forces air into the center of the rotor. On the 944, I believe the kit has hose that routes to the front valance. If the air will exit your hub, you can get stainless plates from Smart Racing, or make your own, to keep the air in the rotor.

Chris Bennet

The OG Racing Cool Brakes kit already includes the hub blockoff plates or at least they did when I got mine years ago. If you get another brand may have buy the blockoffs seperately or make them like Bill G. said. Also the OG ones have 3" hose vs 2.5" for the others. -Chris

Coleco

I am going to be doing this also. I am a little confused here.

Should I remove the backing plate(dust shield) and fab a bracket with a hose attachment?

OR

What about cutting a 3" hole in the factory backing plate and welding a 3" diameter by 2" in length(or whatever amount is needed to attach the silicone hose) steel tube to the plate? Do you think the OE backing plate will help keep the cool forced air at the rotors? Or would removing the backing plates help cool the rotors better?

What part of the rotor would be the ideal place to aim the air? Before the pads, after, or other side of rotor?

I would think right after the pads would be the best place to shoot the air at.

E. J. - 993 Alumni

I think the intended effect is to direct the airflow directly into the center of the rotor so that the cool air blows out the cooling vanes and cools the rotor uniformly. So direct the air at the center of the rotor as best you can.

E. J.

keith

E.J. is correct. Air should be directed INTO the hats, to be spun OUT of the vanes in the rotor. Cooling the inside FACE of the rotor will actually WARP them.

The backing plate issue is less relevant than proper location of hose. If you are fabbing it up yourself, modifying the factory backing plate with a hose mount is a good idea because you solve your -to spindle- mounting problems.

JUST make sure the air is going into the CENTER of the hats, not the face, as Adam and E.J. have said...

BrianKeithSmith

Exucse my stupidity - but I need a definition of the "hats".

What are you referring to. Maybe I just have a different name for it...

Brian

BrianKeithSmith

Also, Keith are you going to be at VIR this weekend?


Brian

keith

hats - the center, raised area of the hub/rotor.
(does that make sense?)

and, no.
(wrenching and camping)

BrianKeithSmith

Makes sense now.

Brian

Coleco

Well "hats" off to everyone that helped straighten me out on this.

I will use the factory backing plate and fab the hose mount to it and aim it into the hat.

Would you guys suggest removing the rest of the backing plate that I don't use to weld the hose mount to or leave the factory plate? Pros and Cons of the backing plate would be great.

keith

keeps rocks out of you calipers/pads?

Adam Richman

Coleco, I would agree with keith that without the backing plates (heat collectors) you will pick up debris. I can attest to this seeing that everytime I swap rotors after an event, at least one of the front rotors has a tire worm in it (and I have the vented backing plates so that should be hard to do). I would think this would be ok provided you at least remove the rotors to clear out any trash.