Topic: Help.. too much rear brake! What direction do we go?
I thought it would be a great idea to take the HUGE Wilwood brakes off of our old Caprice and put them on the little RX7 we run now. The problem is that we now have too much rear brake, and I'm out of adjustment and am at the point of needing to change hard parts and am conflicted on what to do next. On the caprice we ran the factory master, which physically won't mate up to anything on the mazda. On the Caprice we had no issues with the setup, but he car was 1200 lbs heavier and had a much longer wheelbase.
Current setup is:
6 piston front calipers (1.75, 1.375,1.375 pistons)
4 piston rear calipers (1.375, 1.375 pistons)
1.125" straight bore master
wilwood distribution block & prop valve
13" rotors all around
Same compound pads all around (hawk DTC60)
same diameter tires all around.
Even with the prop valve turned all the way out (max rear restriction) the car will wheelhop near the end of the braking zone in the rear under heavy braking in the dry, and is un-driveable in the wet- the rear just locks first and comes around.
My initial thought was to go to 1.25" piston rears to reduce clamping force and also go to a DTC50 in the rear. When I called Wilwood to confirm, the tech (who seemed to be unsure of himself) said I should actually go BIGGER on rear pistons so that they take more volume to move. My issue is that while in theory this sounds good, the next size up piston for our caliper is 1.5" so it would result in a significant increase in clamping pressure, and in my mind, make the problem worse.
So here are the ideas we're bouncing around in addition to going with the less aggressive rear pad:
1- go to smaller piston rear calipers
2- go to larger piston rear calipers
3- add a restriction to the rear brake line before the prop valve to reduce the volume of fluid
4- try to find a stepped bore master
or any other ideas ?