I recently had PFC race tech help me with a brake issue on my spec racecar. Here's the back and forth, pertinent info underlined. Your rotors can take the heat, the pads however couldn't. Race pads on even the stock steel rotors should put your face thru the windshield. I use PFC, sometimes Pagid. Also keep in mind if your using DSC, it's modulating your brakes and putting heat into them you may not even be feeling.
I instructed at COTA for a Ferrari event last year, the pits had a line of F cars getting their rear brakes worked on. Some drivers were using traction/stability control as a total crutch, pads were melting, fluid was cooked, smoke coming from their CCBs, horrible driving. These were 458s and piggy Californias, the older cars no problem.
Quote:
1. With the knockback, does the class allow 2-piece discs?
Only OEM cast one rotors piece allowed
2. With sealed bearings in the hubs, does the preload go away when the car comes in from the race track?
Unsure, however one bearing is starting to make noise when cornering and may need to be replaced.
3. We need to get the discs, pads painted up and the calipers stickered up so we aren’t so blind as what’s really going on here.
I've ordered ti barriers, caliper stickers and temp indicator paint to get data.
4. Brake pad Ti thermal barriers can be purchased from http://hardbrakes.com/
5. Discolored brake fluid means the caliper’s bulk temp is in excess 190c. 210c is the limit for the seals. It’s likely time to refurbish the calipers.
Planning on doing this.
-Brake fade is when the pedal is hard, but after a period of time the braking efficiency starts to diminish.
Not getting this
What brake fade is when the system gets hot enough to cause distortion or compressibility or something in the hot end of the brakes becomes thermally instable like the brake pad. (08 compound is good to 800c which is 150c higher than the iron in 1-piece OE disc) This instability causes non uniform distribution of the friction materials and the end result is a loss of brake efficiency. (In layman’s terms, the car losses stopping power for the same effort over time)
-going over center on the brake pedal and loosing mechanical advantage, effect is soft pedal and lost efficiency.
-aggressive "jump in" from the initial apply and the ABS strategy implements a "preemptive mode" and pulls pressure out of the system there by reducing "bite" in an effort to maintain threshold tire grip,
Help me understand please
There’s a 1.5hr technical seminar I do for PCA, Porsche’s Tech Tactics, SCCA National convention, Performance Racing Industry and David Murry Trackdays that covers this. We will have a video on this but it’s a huge amount of work to edit it so it’s not on line yet.
I will be in Austin for the IMSA/WEC race Sept 15-21, 2014.
Darrick Dong
Director of Motorsports
Performance Friction Brakes
ddong@performancefriction.com;
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