Drilled Rotors
 

I hope this isn't a stupid question. I was at Sebring this weekend and was looking at the drilled rotors on my Carrera S. I noticed that almost all of the holes are packed solid with what I suspect is mostly brake dust. Should they be cleaned out to maximize air flow and cooling?

Thanks.

yep, and its a nasty pain. all for not as well, as it fills up fast with dust on the first lap. the problem is the holes will crack and that can be a dangerous situation especially at a track like sebring. keep an eye on them and replace them when they start to have cracks near the outside edge or inside edge.

Plugged holes will reduce your braking force. Clean them out by poking the packed dust out with a small screwdriver or equivalent. Rotors need to be replaced if: any crack is loner than 7 millimeters, or, joins two or more holes, or goes to the edge of the rotor.

Regards,

Steel wire brush to clean the holes. Go slotted next time. Last longer. Mike

How do plugged holes reduce braking force?

The round end of a drill bit clampwed in some vice grips works well to poke the dust out too. a right size dirll bit will follow the outer hole right to the inner one. If you use compressed air to clean up after punching out the plugs take care wear a proper dust mask.

Good OCD habit for post track inspection of pads and rotors, very Zen like habit, but like sand castles on the beach, won't last long.

just blow them out with air gun

just blow them out with air gun
 

"just blow them out with air gun." Makes a god awful mess.

If you are lucky enough to have a Porsche car where slotted rotors are available, strongly consider them. They won't be cheap.

I used to take the time to clean them out with a drill bit...takes a long time, and that mess, yuk. On paper the brakes will run cooler with drilled rotors and they will be slightly lighter than a solid rotor...

I finally got tired of the cleaning routine and just run the car with them plugged up. The 993 brakes seem to work just fine on a 25 minute sprint race with stock 993 brakes/rotors, ducted cooling to the front rotors and Pagid Yellow on front, Pagid black on the rear.

Clean them up between sessions if you desperately need something to do!:thumbsup:

Yep, works well especially with a attachment specifically tapered to blow a thin stream. Also blow out your calipers while you're at it....

If you are really anal, use a pipe cleaner soaked in brake cleaner and clean out each and every hole. After they fill up again, and you repeat the procedure, you will be ready for slotted rotors.

When I'm ready to replace slotted it will be!

yes, the only way!! you will never get the stuff out of the rotor with any other method.

funny thing is, not only is this almost impossible to do, its very ineffective, because they fill up in a lap or two anyway! the bad part of this is that you are breathing in brake cleaner. (nasty) and the stuff goes into the vane area of the rotor.

just blow it out with an air attachment. works well.

The original purpose for the holes was to allow the brake pads to out gas when they got hot. The out gassing had sufficient force to lift the pad off the rotor, which in turn required more pedal force to get the same braking force. They were not for cooling per se. Modern pads do not out gas so that need has pretty much gone away. They do help in clearing crud off the pad but that is about it, which is one reason slotted rotors are so popular as you do not have to worry so much about stress cracking as those little holes are not stress relieved. If you think any crud will stay in the vents, do the math and see how centrifugal force is being applied at the rpm they are spinning. Sit back have a cold drink, relax and get ready for your next event instead.

yep, and ive found that the "crud" only seems to fill the hole half way too. :)
by the way, the centrifugal force is not that much on a 1800rpm 150mph rotor. but the dust does pocket to the outer diameter of each hole.

The drilled holes are basically irrelevant. I should have been more exact when I said the vents or slots that are sandwiched in the middle. The air flows from the middle of the rotor out. Which is where you direct the air when you pipe air to cool the brake.

1800 rpm is fairly significant when you don't have anything to brace against.