Ray Calvo

All I can say is the best braking car I ever had was my old '84 Porsche Carrera Turbo-Look (regualr Carrera with 930 body and brakes). With the drilled rotors on that car it could outbrake pretty much any street-registered car on the track. My 993 can't match it.

Drilled rotors probably do have a decrease in braking efficiency - in the dry, and on initial/first hard brake stab/application. Under continual use like on the track, the cooling effect of the drilled rotors to me would give benefits in added brake cooling. In the wet, I would always choose drilled rotors over undrilled/unslotted ones. This is from experience with my '76 911S with undrilled rotors vs. later '84 and '95 cars with drilled rotors. '76 had a bit of wet braking delay which I don't see in the later 911 models with drilled rotors. Also, my daily driver '98 Audi A4 Avant has suffered from SEVERE wet braking delay ever since the car was new (Audi was never able to fix it). This car had non-drilled/non slotted rotors as OE. A set of ATE "Power Disc" slotted rotors didn't help much. I just went with a combined crossdrilled/slotted rotors a week ago. I haven't had much chance to drive in the heavy rain with bedded-in brakes, but it seems the wet braking delay is significantly reduced, if not eliminated. Dry braking seems no worse than the slotted rotors.

So, I'm sticking with cross-drilled rotors, even if it means (possibly) a reduction in first application dry braking performance and a decrease in rotor life (yes, 993 factory fronts last about 20K miles).

Bill Verburg

Abuse them enough and any rotor will crack, solid, slotted drilled or cast holes.

The trick is to have enough pad and rotor to fiinish your event, anything left is gravy

Abuse


the result

GrantG

Good photos, Bill! Boy, a brake dyno must have one hell of an electric motor spinning that rotor...

jkuniverse

Ron, I've heard the same...the solid rotors have more surface area for the brake pads to grab on to...thus providing more friction = better braking...but then there is the fading due to heat which should be added to the equation...which the drilled rotors have better heat dissipation. So...I guess they perform about the same?

Rezal

I think it's funny how we talk about needing more braking power while M3 guys (and almost every other so-called performance car out there) would die for even a standard 993 braking ability. We get to "cheat" due to our weight distribution, both in braking (rear brakes do more work than your usual front engine car) and acceleration (rear tires get more weight for traction).

Mark,
You just need to use your brakes less