cmerrick

I am having issues with my brake system.

I've got a 2005 S2000, no mods but I am running 225 Starspec's on the front and 255's on the back. I just changed the tire sizes this year.

I've tracked the car about a dozen times in the last 3 years and done about a dozen autocrosses.

The last three times I've been at the track I noticed I was going through rear brake pads faster than normal and my back brake rotors were getting much hotter (approx. 80 degrees celsius)than the front rotors.

I thought it might be a sticking caliper or a bad brake line so I changed those. The rotors are new and the pads are Hawk HP+.

I was at Calabogie (Ontario, Canada) last weekend and I came off the track after my first session and I still had the same problem. Rear rotors were both 80-100 degrees hotter than the fronts and they were smoking a bit.

I've been doing some reading and I am wondering if the proportioning valve that is on the back brake lines might be toast?

I don't know too much about the s2000's brake balance but I do know the two chambers in the master cylinder each operate a front and rear brake caliper. I see the master cylinder runs throught the ABS control unit and the two back brake lines then run through the proportioning valve on their way to the back brakes.

I've heard/read conflicting opinions on whether the proportioning valve actually reduces the pressure to the rear brakes vis a vis the fronts or if it just balances the pressure as between the two back brakes.

Can anyone give me any ideas here?

Chris