I was told that Wilwood's slotted & drilled rotors (as opposed to just slotted) were susceptible to cracking near the drill holes due to the heating and cooling cycles. Has anyone heard this before? I figured it would probably be more of a possibility with any drilled rotors, but is it really so bad that they should be avoided altogether? If there are rumors or stories about it, is it just Wilwood? I'm not planning to be doing any heavy track or autocross driving, so should I be concerned?
Yes I heard that drilled rotors in general will crack and might "explode" if subjected to intense heat cycles..Not just Wilwood..I have Wilwoods and got the slotted only because of this exact problem..I may be wrong but the drilled rotor is only for looks..
With a car this light you do not need drilled and slotted rotors unless you are doing track day events with high speed and agressive pads. If you want the "cool look" go with the slotted. I have the stock vaned rotors on my car and they are fine for Auto-X use. You may save a few $$ with the stock rotors and up grade later once you sort out your brakes.
Try the stock ones first and add an agressive pad like the Hawk HP or HP+ (numerious options are out there).
My opinion only:
Save your bucks and go with stock rotors. For a street car drilled and grooved rotors are strictly for show. They will cause your pads to wear prematurely, and they can crack more easily depending on who made them and how. Some companies just buy cheap cast iron rotors, plate them, paint them and drill them or groove them, then mark them up 300 percent and sell them to guys who don't need them. When a drilled rotor does come apart from stress cracking, they really turn into shrapnel. SCCA and other race organizations banned drilled rotors because of this. Really high quality drilled and grooved racing rotors are a high grade casting that is closer to steel than cast iron. The difference is that the high quality rotors don't crack easily but the cheap cast iron ones can crack. If you want to at least have a little racey look, just go with good quality grooved rotor. They still will wear your pads out a little faster but pads are cheaper than rotors.
Back about 10 years ago and before the pads tended to outgas and under hard race conditions there would be a hot layer of ionized gas between the pad and the rotor that decreased the friction coefficient and decreased stopping power. The grooves and cross drilled holes allowed the gas a path to escape under RACE conditions. Modern street and most race pads don't have an outgassing problem and you won't be getting your brakes hot enought to utilize the slots and holes. On a race car brake rotors are an expendable and you pitch 'em every few races because even the best ones crack eventually. A crack in a conventional rotor progresses slowly and they very seldom come apart. They just start to make funny noises and you can feel in the pedal that there is a problem
I've had some experience with Centric slotted rotors and they are good quality at about 80 bucks apiece. You can tell the difference when you pick them up, they weight more than cast rotors and are balanced better and they are plated. I don't have them on my car but if I was going to do a lot of serious track days, the conventional would be my choice. Most race organizations actually ban cross drilled rotors because they are bad news when they come apart on a race track. A few manufacturers like Porsche and Ferrari put them on their production cars, but they are really the best quality rotors and you will have to sell your sister into slavery to buy just one. Even Porsche admits they are really for show.
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Last edited by ROADRACER83; 07-03-2012 at 01:54 AM..
i was told the same thing. But i wish i had purchased the drilled ones. I just ended up getting the slotted ones in the wilwood upgrade, but next time i would get drilled because i prefer the look.
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