Stock sports pads at auto-x

ChrisSlicks

I think your right about the pads but I don't think the tires were overheated as it was doing it on a cold day on the 2nd run. It was worse on a hot day with the sticky pads but it I don't think it's the tires as there was plenty of lateral grip and it never felt like the tires were breaking traction when braking (no chatter, skip or chirp).

The HACK

Huh. That's interesting...Was the course relatively clean? The only other explanation I have, is if you hit a patch of dirt/sand, causing the tires to lose grip, or if someone spilled coolant in front of you. The symptom you described would indicate the brake system is functioning as it should.

ChrisSlicks

The course was very clean. We walked the course in the morning and it was probably cleaner than I've ever seen it thanks to heavy rains earlier in the week. There's not much sand around so the course usually stays very clean unless someone goes off course into the grass and drags some dirt back on.

But I don't think surface is the issue as the problem is repeatable on a clean piece of asphalt on the street. You can make several stops 60-10 were it will be perfect and then as things heat up it gets progressively worse. It could just be my imagination but appeared as though everything was fine until heat soak reached the calipers and brake fluid. I.e. you could make repeated stops and get the rotors hot and everything is fine, then just cruise and let the heat soak in and then things start to go bad.

I took it to the dealer this morning and they couldn't find anything yet. But this isn't surprising as you have to drive it pretty hard on the street to reproduce the conditions. Here's a link to another thread on the issue after I realized that pads were not an issue.

Braking problem, malfunctioning ABS