Sounds like luck of the draw rather than any readily identifiable item -

GT3 fronts on our cars (I have them) can takes loads of abuse with ZERO issues.
Use them hard, have fresh fluid and Pagids (great combiunation, by the way) and go have fun.

Try to find slotted next time - so much better than the old school holed rotors......

Stock 996TT brakes are a PITA and too small when used hard - many problems, I had...

 

Actually I have slotted rotors and still can cook my system (using the same GT3 caliper/Pagid Yellows) at Summit Point raceway if I'm not patient and get hard on braking...

My car is modified, so maybe the added power and velocity is the issue, but regardless, I can make the fluid boil, and have...

Mike

 

Have any of you serious track guys used disc temp paint to see what rotor temps you are running at?

 

I did - if I recall correctly the temps from OEM went from 900 to 700 when I switched to Pagid Yellows F&R a few years back - this was in partial response to HUGE brake issues I had before I switched to GT3 brakes up front.

 

I actually use an EBC Pyrometer with a probe and have seen over 930 degrees when overheating the 350MM slotted two piece rotor and GT3 Caliper with pagid Yellows... This is in the scenarios I described earlier where I'm being "overly-aggressive" with the brake and gas...

Mike

 

What were your signs of overheating?

 

Steering wheel vibration, pedal to the floor, and pumping it to bring a stiff pedal back. Mind you, this is NOT the norm... I also bleed the system before every weekend and use Motul RBF600 or GS610 fluids.

Mike

 

GT3 RS air ducts?

 

YUp... Matter of fact, I'd just swapped to them before this happened...

Mike

 

Mike, Maybe you need to kick it up the final notch and go to Castrol.

 

Al, The reason I don't use SRF is the cost of the fluid. I bleed my brakes before every weekend... Having suffered a brake failure at the end of VIR's front straight, I always bleed the brakes before a weekend. I've only had the issue I describe above with the brakes twice and both times they were cold and I went out really hard on the first/second lap and abused them, causing the issues.

My goal is to replace the master cylinder over the winter, as I'm not 100% sure I don't have an issue with it... I wish Castrol would sell SRF in smaller containers...

Mike

 

Going to try to not sound like a salesman here, but Brembo has a great racing fluid called LCF600+, which comes in 500ml bottles and is much cheaper than SRF as well.

Also, over the last couple years, we've run into some issues with street-based calipers running SRF and high brake temperatures (and only at high temperatures). At elevated temps, it becomes corrosive to the alloy used for the pistons and has resulted in extensive pitting of the pistons and leakage. Our racing calipers use different alloys for the pistons to avoid this issue. This problem is not present with the Brembo fluid.

I don't have reported problems in conjunction with other fluids, just the SRF.

 

Actually, I was also told about problems with Motul in Cupcar brake systems as well... something about one of the chemicals in it causing serious issues with the seals.

No issues with it in OEM showroom systems though.
Mike

 

I hadn't heard that. The seal material in the Cup calipers is no different than the "regular" street calipers. As with the problems with SRF, maybe it has only become apparent at the high temps encountered with racing applications.

 

Call Robert at Lufteknic (I believe he is a vendor for you guys) and he'll be able to explain it. I'm sure I'm leaving something out.

http://www.lufteknic.com/

Edit: Thinking back, I'm trying to remember, but he may have mentioned something in regards to mastercylinder and failures... Ugh, this it gonna drive me nuts... It came up because he had reservations over me using Motul, and did research that confirmed it was fine for me to use...

Mike