Quote:
Originally Posted by Shorts
We can rule out the brake drying feature as well, as I never use auto headlights or wipers.
I will start with removing the factory ducts come spring time. Would you recommend a more robust brake fluid? RBF660?
I just saw your comment about the blue tint - I failed to mention earlier than I get a slight vibration under medium (~50mph) to high speed braking since the last track day - should I start with an alignment? I'll post a pic of the rotor this evening after work.
Thanks again!
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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.
