New Rotors - Need Real Experience

[Jcon]

I have to order new front rotors for my 81 SC. I will do 3 DE's this summer and maybe 4-5 auto crosses. The question is ...is there any true ( read noticable) difference between slotted / cross drilled and Standard in terms of actual performance in the above application. I've heard the theories...but has anyone here really noticed a difference. The cost difference is real so I want to make sure the performance increase is real.


Thanks

Jeff C
81 SC

[don911]

I'm putting slotted rotors on the front only because I got a good deal from someone on rennlist. I haven't installed them yet so I can't speak to any performance gain, though I don't believe there will be any. For 3 DE's, I would save the $ and buy OEM rotors. Use the money and put on some good brake pads and a brake cool kit. Just my opinion.

[expat]

This has ben discussed at length in previous posts and I think the main thoughts expressed were:

Stock rotors are excellent and suit most everyone.

Cross drilled are good for those doing serious track work where brake heat may be a problem.

Slotted and cross drilled are good in wet conditions as it provides opportunity for water to be vented away a bit.

Slotted and cross drilled are good for reducing the gas build-up between the pad and the rotor.

The jury seems to be out still on the deep frozen rotors.

For the megabucks - maybe the stock ones are best for your (and most peoples) use.

Oh - the crossdrilled and slotted were deemed to look cool if nuthin else

Cheers
Mark

[Jcon]

Thanks

This has been discussed at length, but when I searched the archives I read thru lots of theory and very little experience. I was curious if after people had spent the money they actually noticed a difference in performance.

I agree...with upgraded wheels the drilled and slotted look much cooler.

[Bill Verburg]

Nice summary just one minor quibble,

Cross drilled are good for those doing serious track work where brake heat may be a problem.

The stock rotors are ok for lighter less powerful cars. Starting with Carrera 3.0 and SC/Carrera the stock rotors are a definite weak link for serious track work. They are still adaquate for the ocassional D.E. or Autocross where appropriate pads, fresh h/p fluid, Ti shields, and ducting will all help. Cross drilling them will not help and in fact will promote cracking sooner.

Carrera rotors and calipers are a nice step up for SC

The only drilled rotors I would reccommend are the 930(304x32mm) size or larger which have the ~4mm cast in holes.

Imho cryo-treating does not add value

[Jcon]

Bill

What do you think of the slotted rotors. It looks like a minimal amount of extra machining to the rotor at double the price. On the other hand if they truly offer a cooling difference maybe it's worth it. I expect my track time to increase over the next couple of years as I get more free time.

Alson is the carrera caliper upgrade a straight bolt on upgarde for the SC?


Thanks

[Bill Verburg]

The slotting and drilling are not for cooling. Their purpose is too provide an escape route for outgassing at elevated pad temperatures and water in wet conditions. The slotting IMHO is worth it. But each to his own opinion/budget.

The Carrera caliper/rotor setup is a bolt on for the SC, though there are some issues with obtaining proper f/r bias. One solution is a bias valve on the rear circuit. Another is to widen the SC rear caliper for use with the Carrera rear rotor.

Lots of people do this mod but use the Boxster front calipers with the Carrera rear caliper and carrera rotors all around

If you are going to spend a lot of time on the track and class rules allow it 930 brakes at a minimum are the way to go.

[avi8torny]

I have the slotted on the fronts and did many track days last year with stock pads.....no fading or complaints once.....just installed another set of OEM pads for this year. Change your fluid to blue.

[cstreit]

I agree with Bill (of course)

Slotting and drilling do not improve cooling... If you must go one way, DO NOT get drilled. They will crack. Slotting helps get rid of gasses and helps with rain stopping.

I use stock on my racecar though, because of problems with both slotted and drilled. I notice the difference, but not THAT much...

[Jcon]

Chris

Thanks....If you can get by with stock on your race car, I will certainly be fine. Besides I can use the extra cash for the new fire extinguisher.

Thanks