ok, so why does everyone want cross drilled rotors?
01-17-2006, 05:56 AM
#12
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so with less surface it can cool down faster but..
wouldn't it heat up faster too since you're working with less mass? the extreme heat up and heat loss...wouldn't that cause rotor warpage?
01-17-2006, 06:19 AM
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actually, they have more total surface area
because the insides of the holes increases the total surface area quite a bit without decreasing the mass too much. The extra surface area allows them to dump more heat (like the heat sink on your CPU - works better with fins than a solid block of aluminum would) The physics of it make perfect sense, the cross drills create better air flow, allowing your rotors to shed heat better, which, in theory will prolong the life of your pads and allow them to work better. They're not heating up faster and cooling faster, because those two things will always be offsetting each other, unless you're just running you car up to 100 and braking as hard as you can over and over again. Of course, I don't think most people brake hard enough and often enough to get their rotors hot enough for it to matter, unless you live in a hilly area or drive very aggressively. So, its probably for the look.
01-17-2006, 06:41 AM
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Re: actually, they have more total surface area
i always thought heat is absorbed by mass.
for example..it would take a lot more heat/energy to heat up a 20 pound of iron than is it heat up a 10 pound of iron. when you drill the rotors you lose mass.
i thought that's one of the point of getting bigger rotors...more mass in the rotor to dissapate heat..no?
back to your example...if you have a solid block on your CPU..it'll take a while for the block to heat up...but it also will take a while to cool down also. more a gradual heat and cool cycle. when the heatsink is finned...it would heat up fast..but it will cool fast also since there's so much surface area for air to pass through. wouldn't that introduce rotor warping?
also with drilled rotors they have a tendency to shave (cheese grate) the pads a little when braking. wouldn't that decrease pad life overall?
at the end i think we both agree that it's more for the looks than anything else.
for example..it would take a lot more heat/energy to heat up a 20 pound of iron than is it heat up a 10 pound of iron. when you drill the rotors you lose mass.
i thought that's one of the point of getting bigger rotors...more mass in the rotor to dissapate heat..no?
back to your example...if you have a solid block on your CPU..it'll take a while for the block to heat up...but it also will take a while to cool down also. more a gradual heat and cool cycle. when the heatsink is finned...it would heat up fast..but it will cool fast also since there's so much surface area for air to pass through. wouldn't that introduce rotor warping?
also with drilled rotors they have a tendency to shave (cheese grate) the pads a little when braking. wouldn't that decrease pad life overall?
at the end i think we both agree that it's more for the looks than anything else.