urquattro20Vt

So my car is ready for front rotors - I already have pads - so what are people doing for stock '91 3.3 rotors? Are the Porsche rotors proven to be better than Zimmerman or other OEM suppliers - whether it be lack of warping or durability? Any experience with Girodisc here? (I just bought a set for my highly modified Audi S4 (350mm rotors under 6 piston Cayenne 18Z calipers) but its basically a custom application so factory rotors not an option).

Thanks-

Brandon
'91 911 Turbo
'00 Audi S4

bweSteve

Hey Brandon,

I have a full set of front & rear rotors that I took off my 3.3 back in Oct 2015. I've had them in boxes since. You can read all about them on this thread...

https://rennlist.com/forums/964-turb...fferences.html

I can't believe it's been 2 yrs, but I still have them.

PM me if you want to work something out.
=Steve

urquattro20Vt

I'm contemplating having whatever rotors I get cryogenically treated...

Anybody doing/done that on this forum? - and had noticeably longer life span from the rotors?

Brandon
'91 911 Turbo
'00 Audi S4 highly mod'd DD

bweSteve

The barrel on my Benelli Super Sport is Cryo treated and takes a LOT of heat on back-to-back rounds.

never heard of it on rotors. I thought they needed to sub freeze it down to -300 degrees when they were forging the metal. Paul? You're the metal guru...

=S

cobalt

How hard do you plan to push them? They last a long time even on the track. But it all depends on how hard you drive and what pads you use.

Paul would probably know better but my understanding is they are cast not forged and would require a heat treatment process to give them strength. Usually bringing it to its solidus state or near close to liquidus and then quenched followed by an artificial age. I don't know if the cryogenic process helps or not but to me rotors and brakes like tires are wearable items and it is a factor of how you drive. I would think the benefits aren't worth it considering the price of rotors over 50k miles maybe 40k if you push them hard or 5k if you track them.

urquattro20Vt

Cryo is done post manufacturing - yes it is a freezing process. I've had it done on internal transmission parts (on my former Audi quattro) to increase strength - and Tire Rack even sells Cryo treated rotors. It's a known thing to increase strength/life. But yes rotors are a wear item. I'm not tracking the car but the car gets pushed somewhat hard in curvy hilly mountain driving...

Was really just curious if anybody was doing it here. Figured why not increase life if you can, at a reasonable cost....

FYI Sunset sells new 3.6 fronts at $209 ea. But man those rears get ya. Not as bad as the GyroDiscs for my S4 ($375/each front) but not far off. $292 ea for rears from Sunset...

Brandon