Should I use drilled Performance rotors for track or street?

[GaryS]

I bought a second set of rotors to use with track pads so I won't have to bed them in over and over. The new rotors are drilled and slotted BMW Performance rotors because they cost less than stock. My instructor today said drilled rotors suck and I should use them for street and the stock rotors for track. Does anyone agree or disagree with that?

[DOUT]

Drilled rotors crack rather quickly when under stressful use (on the track). Either use stock rotors or slotted rotors on the track.
Slotted rotors have the same cooling effect as drilled without leaving you as vulnerable to cracking

[GaryS]

Oh, okay. Do drilled rotors wear the pads any faster?

[fourtailpipes]

drilled - best cooling, allows gas expulsion, generally lighter, cracks easily, wears pads a bit faster, looks fancy
slotted - good cooling, allows gas expulsion, won't crack, wears pads a bit faster
blank - no cooling advantage, does not allow gas expulsion, won't crack, normal pad wear

use your new rotors on the street. oem rotors will be fine for the track until they're worn out, then go for some slotted rotors. slotted/drilled rotors will wear pads a tiny bit faster. what pads are using on/off the track?

[GaryS]

Thanks. I'm currently using Cool Carbon S/T for street and track. I ordered Hawk DTC-70/DTC-60 for track, or at least for particular tracks that have long fast straights.

I also ordered BMW Performance front rotors and regular BMW rear rotors. The Performance front rotors are $247 with free shipping from ECS, which seemed too good to pass up.

I'm a little disappointed about not getting the 3 lbs per side weight advantage on track if I use the drilled rotors for street, but I guess it's not that big a deal.

Meanwhile it sounds like RacingBrakes might have two piece rotors for us next year. If they do, I'll be upgrading to those in front for sure when they're available.

[fourtailpipes]

Originally Posted by GaryS

Thanks. I'm currently using Cool Carbon S/T for street and track. I ordered Hawk DTC-70/DTC-60 for track, or at least for particular tracks that have long fast straights.

I also ordered BMW Performance front rotors and regular BMW rear rotors. The Performance front rotors are $247 with free shipping from ECS, which seemed too good to pass up.

I'm a little disappointed about not getting the 3 lbs per side weight advantage on track if I use the drilled rotors for street, but I guess it's not that big a deal.

Meanwhile it sounds like RacingBrakes might have two piece rotors for us next year. If they do, I'll be upgrading to those in front for sure when they're available.

all good stuff! the DTCs are great pads. you'll want to use them on every track. also worth mentioning: a track with a long straight is often less-brake-intensive because the duration and speed (meaning cooling airflow) of the straight allows your brakes time to cool. overheating issues are common on tracks with more frequent braking. believe it or not, the intensity of the braking done has less of an impact on heat buildup than simple duration on/off the brakes. keep your braking zones brief and you'll get the most out of your brakes.

[IGoFast1589]

Besides what everyone else said, the drilled rotors have less mass so you may notice it's more willing to accelerate if the weight savings isn't marginal. I would do what your instructor advised. You would have to work your rotors hard to get then to crack, but you should still use the stock blank rotors on the track.

[GaryS]

Originally Posted by fourtailpipes

believe it or not, the intensity of the braking done has less of an impact on heat buildup than simple duration on/off the brakes. keep your braking zones brief and you'll get the most out of your brakes.

An instructor told me that just a few weeks ago. Anyway, that's what I'm trying to do. Thanks.

[xerox445]

Slotted or blank is the way to go. The mass of our rotors is already low due to them being thin comparatively.