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  • #16
    slotted owns...end of discussion...


    • #17
      MR- EBC makes the Greenstuff pads.

      Menchi- Notice that on most professional race cars, they only use drilling or slotting. Combinations are few and far between. You are right on the money about drilled-and-slotted rotors being redundant... one loses too much surface area. If a drilled or slotted rotor is designed right, it'll cool just as effectively as a drilled-and-slotted rotor, but with more surface area. There's only so much gas/heat to dissipate.
      Drilled rotors tend to crack if the holes aren't chamfered. Also, a lot of the high-end teams that do use drilled rotors have them cryogenically frozen to help prevent cracking as well.

      On braking balance: now we're treading on advanced ground here. If you're going to seriously mess with brake balance to get the most from the car, expect to spend a lot on new tires. Remember that you can't just set the balance from a couple half-pressure stops from 60; you also have to take into account the stability of the car slowing at full pressure at speeds upwards of 120. I would recommend a higher-speed testing regimen for a street driven car so it'd be more manageable under emergency conditions. For the track, well... every track is different. You'd probably have to mess around to find the best setting. If you must set bias on the street, find a very desolate area with nothing to run into and be prepared to make the trip home with flat-spotted tires.

      Nemesis- I agree that slotted rotors seem to offer the most advantage, on the racetrack and off. They are the least likely to crack and, with directional vanes, cool exceptionally well.

      A novel idea I've seen implemented in the BMW club racing circles is a cooling duct which terminates in a cooling plate attached to the hub. The plate forces air through the rotor's internal vanes and out of the rotor. Thus, the rotor is always cooled and the brakes then run cooler. Here's the link:


      • #18
        Those are the kinda of cooling ducts I'm talking about - cheap to make and all benefit! It's not just the BMW guys who do it either. Anyone serious about braking peformance will benefit from the installation of cooling ducts.

        I had ducts on my Subaru that were made from a 4 1/2" foil dryer vent hose (although a large shop vac hose may work better as long as the last few inches are wraped in foil tape or a piece of aluminum tubing to resist melting from braking heat) connected to a hole that I drilled in the OEM backing plate. I cut a 4" hole with a hole saw and then used a jig saw to cut a bunch of concentric cuts to the 4.5" line that I drew. Next I folded those tabs out away from the rotor and slipped the hose over them. A good wraping of foil tape and a number of 1/8" holes and washer-fitted pop rivets later I was good to go. Never had any problems and the thole deal cost about $20 (one hose can stretch for all 4 wheels depending on where the vents are).