SS Brake Line + Brake Pad + Rotor Installed~

[Loren]

Originally Posted by supmet

I really don't see how something with more mass and less surface area will dissipate heat better than something with less mass and more surface area.

The holes in brake rotors have NOTHING to do with surface area. They don't have anything to do with cooling, either. Their original purpose was to give the gasses produced by old-school brake pads (that haven't been used in over 40 years) someplace to go. Now, they're almost entirely there because folks think they look cool. They do add a bit of lightness, that's about their only true benefit.

More mass in a brake rotor allows them to absorb more heat over a longer period of time. Talk to Spec Miata racers about brakes. A lot of those guys run the smaller 1.6 Miata brake rotors because they're lighter and every little bit helps. BUT... they can tell the difference between a NEW full-thickness (and thus full mass) rotor and one that is worn down to its service limit. A new full-thickness rotor (with more mass) will dissipate more heat and resist fade longer than it's thinner cousin.

As far as cracking, I don't understand why 911 turbos, skylines, and other 400-500 hp cars can run with drilled rotors stopping their much heavier, much faster cars without cracking. I'm pretty sure these will hold up for a 2 minute auto cross run just fine.

The reason they HAVE the cross-drilled rotors is purely bling. People like you EXPECT them to have it... just like the ridiculously large and heavy wheels that are popular these days. The reason they work on those cars is equally simple. The engineers who designed the car over-engineered the braking system to prevent heat-related problems. This is a wildly different concept than taking an economy car like a Yaris and simply fitting a set of rotors that someone has taken to a drill-press. (and don't assume that there's much more involved in making these rotors than that... there isn't... most aftermarket cross-drilled rotors begin with a standard blank)

Holding up for a 2-minute autocross run? I never said ANY brake system wouldn't do that! I said "race track". I'm talking about lap after lap of braking from 90-50, from 70-30, from 80-40... over and over. I'm NOT making this up, I've seen cracked drilled brake rotors at race tracks on everything from Porsches and Audis to Mustangs.

Also, with the stock rotors and pads I had problems with glazing the pads and warping the rotors. So far the R1 drilled and slotted rotors and carbotech pads have lasted longer than stock ever did, and they still look pretty much new.

Did you ever try just the Carbotech pads with the stock rotors? Hmmm?

[Brian]

What about just slotted rotors as oppossed to cross drilled and slotted? Any difference there?

[Loren]

Originally Posted by Brian

What about just slotted rotors as oppossed to cross drilled and slotted? Any difference there?

Not as likely to crack, but no real benefit. Again, trying to address the outgassing issue that modern brake pads don't have. They do tend to act as a cheese grater and wear your pads quicker, though.

[silver_echo]

i am curious for those of you that have the slotted rotors or know more than i do about them... which is better? oriented to have the slots come out from under the pad during forward motion from in to out or from out to in? why? just wanted to ask because i am planning new brakes for my car this summer, and was wondering which way i should index them...