Quote:
Originally Posted by dradernh
It's normal when you're over-heating the brakes. IIRC, there have been a number of threads about discoloration of the calipers due to heat.
The PFC08s you're going to get may help with that. That's because brake pads act as a heat sink, thereby slowing the transfer of heat into the caliper and the brake fluid.
Nevertheless, our cars are fairly heavy and powerful, so if you're on a heavy-braking track and aren't yet skilled at running quickly while minimizing brake use, the brakes may well get too hot.
I believe the solution to our cars' issue with getting the brakes too hot is to get more air into the center of the rotor. To that end, I'm having some brake duct work done early next month and will post photos and the on-track results in the track section.
I use these two products to collect brake system temperature data: https://www.amazon.com/Brake-Tempera...dp/B075MR5LBW/.
To find out how hot your rotors have gotten, you match the color that the brake temp paint takes on to a color card that comes with the paint. You can use that temp to approximate how hot your pads are getting. Then compare that temp to the pads' published heat range to see where you stand.
I use 350° as the maximum temp I want my calipers to get - that's to (hopefully) preserve the pistons' dust boots. Ideally, the caliper temp will remain well inside the maximum temp of the brake fluid - if it doesn't, you'll boil the fluid.
Below are examples of my results after a recent event (both are hotter than I'd like them to be):
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Wow, very helpful post, thanks a lot!
Yes I guess the temperature is the key and different pads have quite different working temperature ranges. The EBC yellow stuff seems to be not very good at high temperature area and I think overheat made it wear even faster. PFC08 will definitely help in this regard.
I used to have StopTech sport pads on my car and I drove in a similar style using the brakes. They were not as bad as this one in terms of overheat and wear. The changed variables since then are:
1) I replaced the old PS4S tires with RE71R. Stickier tires will for sure increase the workload of the brakes
2) I changed the wheel size from 19'' to 17''. The free space around the rotors and calipers is smaller than before thus I may get less air flow and worse cooling. However, I'm not sure how big role this factor plays. So I'm very interested in your brake duct work. Please keep us updated!
Now I'm using RBF 600 brake fluid. The dry boiling point is 312C. I did get mushy feeling on the brake pedal late in the day. But how can I tell if the fluid is boiled or not?