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Old 08-15-2009, 06:01 AM   #19 (permalink)
JoeD
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Quote:
Originally Posted by Cjanik View Post
^^ besides the theory of hype, your, and the OP's, suggestions of that they are useless doesn't go anywhere.

you are both saying that no proof of benefits = hype, well then show us proof that it doesn't work and its function is hype. the burden of proof is on you and you have not delivered.

I can name half a dozen reasons why its better to have cross drilled, just as you can name half a dozen reasons why its better not to have them, so dont bother with that - go for the testing thats been done and show the results.

-edit- wanted to mention, a well known fact of drilled or slotted rotors is the holes allow the gases and dirt to pass through the hole, versus piling up between the pad and the rotor acting like ball bearings, this allows a much better "bite". I wanted to point this out because you said it gives less grip due to less surface area. The same goes with heating, less mass for heat dissipation? where's the heat going to go if there's no air/gas moving through transfering the heat? thats where the holes come into play - more air movement = less heat. You dont need rotors to prove that, look at any part that creates heat and how it removes the heat.
LOL.

I'll quote GRM:

"Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." ...It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it...Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)"

Please read, mainly the entire first post if anything. Some good info.

The real deal about cross-drilled and Slotted Rotors - IWSTI.com: Subaru WRX STI Forums

After that, dig around on the websites of manufacturers of brakes and see what they have to say about drilled vs. slotted rotors. Remember, it's in their financial interest not to talk down on essentially half their products, but there comes a point where you just cannot lie. When you're done doing that, take a peek behind the wheels of a Formula 1 or Le Mans car.

Do I speak from first-hand experience as to which one is better? No. All the cars I have driven on a track competitively or in HPDEs have had conventional and/or slotted rotors so I cannot compare. Does that make my opinion moot, though? Hardly. Doing so would be along the lines of dismissing someone's opinion that an eBay electronic supercharger or "Tornado" does not provide gains simply because they haven’t tried it.

And for the record, the burden-of-proof always lies on the party making the claim of an advantageous development or idea, not the inverse. Now show me a manufacturer, racing-team, or seasoned road-racing enthusiast who has come out in favor of drilled rotors.
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