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      03-18-2013, 06:37 PM   #78
r53s65e90's Avatar

Drives: r53 s65e90
Join Date: Mar 2009
Location: San Jose, CA

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Originally Posted by ortho281 View Post
I think the only difference, may be that the 380/380 will have better heat dissapation and heavier upsprung weight over the smaller 365/345 set up.
I went through the same thought process about this before deciding on the 365 kit. 380 has definitely more heat capacity but what does this mean? My calculations were as follows: Based on geometry the 365 rotor is about 4.6% lighter. Given that all other stuff is the same (slotted, same caliper, same pads, same cooling effectiveness) and assuming all kinetic energy goes into heat to the front brake (which is the absolute worst case) here is what it means: If you fade (=boil fluid) the 365 kit during braking from 110mph to 40 mph, the 380 kit will fade from 112mph to 40 mph. To me this means NO perceptible difference, especially if you factor in cooling and the fact that part of the heat will go tot he back brakes. So I get to keep my 2 sets of stock 18s too.

I didn't bother with rear brakes calculations as I consider them a cosmetic mod.

I couldn't make the same calculations with the stoptech setup because caliper and pads change from the 380 to the 355 kit.

Would be nice if someone could replicate my findings.