02 WRB WRX Wagon, '00 STM RS
Oops! My bad. I did get ya mixed with noTe.remember who you are arguing with, i'm not the guy that said you will die on the street in them
False. By drilling/casting holes in a rotor, you are increasing the surface area, decreasing the mass of the heatsink. So now the rotor has slightly less mass, and has slightly less surface area in contact with the pad, but more surface area in total to cool itself quicker.furthermore, at the end of the day a brake rotor is nothing more than a heat sink. the more capacity a heat sink has to absorb heat the better it will do its job. by drilling holes in the rotor you are reducing the effective surface area (capacity to absorb heat) of the rotor and building up more heat on less surface area. this will often lead to cracking around the holes (ive seen it and done it myself). the same applies to slotted. you are removing metal from the rotor that would otherwise be absorbing heat.
More Surface area=Good thing. That's why 2.5 guys upgrade to H6 rear disks on the cheap, because they are vented, vastly increasing their surface area. More surface area, the quicker the disk can cool down.
Thank you for your accurate perception. Do you really think the best manufactures of cars in the world simply put the 'drilled' (which they ARE NOT) rotors on their highest performance cars for "bling" and not 'performance' at the detriment of the owner/driver and the lawsuits certain to come from their poor braking decisions??? :bonk:Automakers like MB and Porsche know this and apply the proper means the reduce the likelyhood or cracking in their drilled rotors.
ha ha did you read what I said ... how much air do you think is going to move through those holes with the rotor spinning.... hardly anyif you drill holes you ARE reducing the surface are and therefore reducing the friction/braking force applied. however with these added holes air can move quicker in and around the rotor cooling it quicker and removing heat from the rotor itself.
I know they are not literally drilled, and do not believe that they are in danger of breaking, but those "high performance" car companies actually are not making race cars they are SELLING cars and brake calipers that look cool are MARKETABLE. Its not that they will perform noticeably worse then non drilled ones but they are more expensive to make for no benefit. If you look at most Porsche race cars they take those rotors with holes in them off, and put on either blank or slotted 2 piece rotors.Thank you for your accurate perception. Do you really think the best manufactures of cars in the world simply put the 'drilled' (which they ARE NOT) rotors on their highest performance cars for "bling" and not 'performance' at the detriment of the owner/driver and the lawsuits certain to come from their poor braking decisions??? :bonk:
good drilled rotors should not crack. drilling after casting produced interal stresses and if not annealed then the formation of cracks is inevitable. this is usually seen on cheaper rotors, if they are as cheap as a blank stay away.