what do you guys recommend? stock, brembos, stop tech? I think my stock ones are done. i was getting some bad brake shudder the last couple sessions on sunday at VIR.

 

Brembo blanks from http://www.collettimotorsports.com I think they are like $35 each and $90 for a shipped pair.

BUT before you get them, let me guess, you were using Panther Plus, or some other streetable pad? Before you go plunking down for a new set of rotors, try driving on them for another 2 weeks and see if they don't smooth out. Could just be the pads leaving crap on the rotors. I used pagids in Alcon calipers on an S4, and they do this all the time at the track.

Warren

 

Good guess Warren. i am using the panther plus pads. so that is normal for them to do that on the track? i was going to get an extra set of rotors anyway for track use. Thanks

 

I think that is normal for the P+ pads. I had the same issues towards the end of the day on Sunday, and I talked to somebody else who had the same vibrations. (Aleph, maybe.) They seem to be fine now driving around town.

I did, however, notice some small stress fractures on the front rotors yesterday. Should I be worried?

-Floyd

 

i've had vibrations while hot since i started tracking my car, first on stock pads, then on R4S, and most recently on P+. I too am wondering if a set of blanks for the track to match with the P+ might not be a good idea...it's not a hellish vibration, but it's noticable.

 

What you are experiencing are "hot spots" on the rotor. These are spots that expand at uneven rates as they heat up. When the rotor gets very hot - when you're on the track, or if you've ever tried a really hard stop from 100 mph - you get shudder. When the rotor cools down, like when you're driving on the street, there's no shudder at all. I assure you, the next time you take them out on the track, they will shudder like the dickens all over again.

Solutions: (1) Replace the rotors. The shudder will be gone. However, it may re-develop all over again over the course of another few track events. (2) Install some cooling ducts to blow air on the rotors. (3) Use a high-quality brake pad (if you're not doing that already).

 

My personal favorite:

(4) Just drive.

Warren

 

Don't be worried, but keep an eye on them. If you track your car, these will eventually turn into real cracks. It's not a problem when you go out on the track; as the rotors heat and expand, the cracks fill in. It's a problem when you come off the track and the car cools down, and the cracks widen. Stress fractures will turn into tiny radial cracks, maybe half an inch long. If you can't feel them with the edge of your fingernail, don't worry about them, but again, keep an eye on them. If they're big enough to feel with the edge of your fingernail, then it's time to replace your rotors.