Apex28

Can someone please explain why drilled rotors are better than plain non drilled rotors and why they stop faster? I think they do but it seems a lot of people think they do not. I'd like to get some opinions on this.

TNTC4VETTE

They vent gases but are prone to cracking under repeated, hard use.

Apex28

Yes but do they actually help stop the car faster?

99c54me

Holes = less surface area = slower stopping assuming same size rotor

The out gassing issue would only be present in pad materials that out gas. I am not aware that any GM pads out gas. After market pads maybe, but they would need to state so.

I believe 99.99% or more of all drilled/slotted rotors are for aesthetic purposes only.

cdkcorvette7

Not really... Holes in the rotor means less surface area for the pad to grab. The original intent (as I understand it) behind drilled performance rotors was to allow gasses that built up under hard braking to dissipate. If the gasses stayed trapped it would have a negative effect on braking. That isn't really an issue anymore as the materials used to make brake pads have evolved and gas buildup isn't really a problem anymore. There is an argument that can be made for drilled rotors in that they allow heat to dissipate more rapidly but I haven't read enough on that to really buy into it yet.

The real downside to drilled rotors is that they're weakened when they're drilled. If you run drilled rotors hard at a road course you're likely to crack an ruin them. That's one of the reasons why most of the guys that run road courses use solid rotors for the track. That is assuming of course that we're talking about your typical steel drilled rotors... The ZR1 along with many other ultra high performance vehicles use drilled rotors but they are carbon/ceramic rotors and are extremely resistant to wear and heat. They also cost $1000+ per rotor...