[ggggbmw]

Thought people might be interested in seeing the results of some brake temp paint after my last track weekend. This was at Road America, with several brake abusing corners, so these definitely got warm. @dradernh has also posted some pictures of temp paint, and these largely echo his. But there are some interesting bits I'd like to point out. This is using the Genesis Brake Temp Paint.

This is a close view of the front edge. The temp paint is nearly burnt off, and the lightest possible shade, indicating a temp over 800C/1500F. Probably well over. This isn't that surprising for our cars, and echo other peoples experience.


The more interesting parts are looking at the other areas I applied the paint. This is a better overall view of the front disc, caliper and pad. If you look at the inner edge of the friction area, you can see a bit of paint from the inner edge down to the hub. The inner edge is again the high temp beige, but the hub area has barely changed color. It's still in the ~400C/750F range. I'm not why that area is so much cooler, but it's inside the inner air inlet area of the ventilated discs. It also might be getting cooled by the aluminum hat, which will dump heat faster than the cast iron disc.

The biggest surprise to me was the paint on the back of the pads, which barely changed color. These still have 10mm pad left, so still thick. But the back of the pad temp color is under 430C/800F. That really shows the importance of thicker pads keeping heat out of the caliper pistons. You can also see the bright red of the daub on the calipers. It didn't change color at all, staying under 360C/670F. I'm really wondering what people are doing to their calipers to get the paint to change color. Flame-broiling them? (btw, the temp paint on the calipers was a bad idea cosmetically. It stained the caliper paint with a permanent dark spot.)


This is a shot of the rear calipers. The outer edge is still the same beige as the fronts, but not quite as bright. This indicates a temp closer to the max 800C/1500F range of the paint. You can see that the paint on the inner edge of the disk is much cooler. In the 400C/750F range. So, the rears are getting used, but not as bad as the fronts. And again, the back of the pads and the calipers are not even exceeding the first temp range of 360C/670F.


These pictures are actually from after the second track event. The pictures from after the first event weren't as good, and paint application on the rotor wasn't as good either. But the caliper and pad paint is after 2 track weekends, and a couple months of street driving. They just never get that hot. The rotors were painted a week before each track event, and the car was driven on the street as my DD, and to the tracks, and normal street driving didn't get the rotors warm either. Maybe just to the point where they started to change color. So, we will only ever see these extreme temps on the track.

[dradernh]

This is good information; thanks for sharing it with us.

I put Genesis' paint on a front backing plate, too, and I got the same color as yours. Given how hot the rotors get, I was encouraged to see temps that low.

I've used Genesis' caliper temp strips to get caliper temps. I can't seem to locate the data, but IIRC I was getting high 300s with the strips placed over the top of the outside leading front piston. I was also getting the same paint color that you're getting on your rotors.

After I had a shop add a set of front brake scoops, the rotor temps dropped ~100°F and the caliper temps somewhere less than ~50°F. We knew the differences wouldn't be dramatic, but at least it was a step in the right direction.

These braking components are still getting too hot. My dust boots show signs of that, and I'm going to replace them and the piston seals with high-temp units.