Quote:
Originally Posted by The HACK
More robust fluid...Yes, but it's not going to cure your brake fade. Especially if, as you said, the pedals are firm but the car's not slowing down. I'd start with the pads, IMO. This car has enough HP to generate enough heat in the brakes that requires something along the lines of Hawk DTC-60s or Cobalt XR-3s or PFC-0X/11. I "personally" would do both, upgrade the fluid to higher end racing fluid AND track pads for that extra margin of safety.
The blue tint is from the material of the rotor heating up and cooling down rapidly, same reason why titanium exhaust tips are blueish purple (except, now-a-days it's done on purpose), it's not deposit. Deposit will show up a dark muddy grey splotches or streaks on the rotor.
The symptoms you describe re: braking sounds more like normal deposit, which is exacerbated by rotors with holes in them, because the edges of the holes catch pad material and leaves behind slight ridges, especially if the rotors are hot enough to MELT pad material.
Here's another question. Did this fade show-up early in the first couple of sessions, or did it show up as you progressed through the day? Like in session 3 or 4? And my next question is, how are you doing your cool-down laps? Do you try and go through an entire lap driving at speed (not coasting) while not touching the brakes?
The reason I ask, and I'm going to explain it anyway whether you answer or not, is because if you're doing 4-5 sessions a day, even if they're spread out throughout the day, there's heat trapped in the rotors that never fully dissipate while you're in the paddocks. Say, after session 1 you come in to the pit with the rotors relatively warm at 300ºF. It sits for 1.5 hours and radiates heat and cools off down to 200º before you go out for session 2. Session 2 builds on top of that heat, and you come off the track at 375ºF, and before you go out for session 3 your rotors are still at 275º...You get my drift? By session 4 your rotor temp, before you head out, is already significantly above ambient.
I would get an infrared laser thermometer, and measure your brake rotor temp if you're experiencing fade in the latter half of the day, and see if the temp of the rotor is the same before you go out. If it's significantly higher than previous sessions, then I would extend the cool down lap longer and attempt to drive the cool down lap without engaging brakes at speed.
Or get bigger/better rotor and more cooling.  |
Interesting point on the brakes getting progressively hotter each session. The fading happened in the 3rd session - it was my final session since I went off track (into gravel thankfully) and spooked myself enough to skip the final two sessions of the day.
On cool down, I barely use the brakes but sometimes brush the pedal by habit.
Please see below a couple of pics I took of the rotors - not sure if the lighting is appropriate enough to determine whether the deposits are problematic?
Looks like I have some homework cut out for me before springtime to research which pads to get and the best way to create a better duct! I find it very hard to accept that this car needs a bbk so I exhaust (no pun intended) all possibilities before I come to that conclusion!
https://goo.gl/photos/GAWbBTFNtYQwBVHj8
https://goo.gl/photos/513NZ7sBxrdGH8en9