Looking for a little input guys, I'm about halfway through my TII front end swap, and have gone to 4 piston brakes front and back. Someone suggested I use the TII brake Booster and upgrade the master cylinder. Re-Speed's Big Brake kits don't mention anything about needing to do it, and I havne't really seen anyone else do it.

How do you guys with 4 pistons feel about the pedal feel / pedal travel / brake power, etc. on your cars? Who's using what boosters?

 

FD booster/master.
Hose from brakemaster-reservoir to clutch master.

 

I'm using the OEM FB booster/MC with a custom 4-pot front brake setup. The piston area is slightly less than that of a TII 4-pot caliper, but it's close. Works fine, with good pedal travel and effort.

If you're using 4-pots in the rear, how are you getting the F-R bias correct?

 

If your using the RE-Speed kit I'm pretty sure there is no provision for 4-pots in the rear. Rear TII calipers are single piston. I have the full kit and my stock master. Zero issues, car stops like it's hit a wall. My passengers hate me!

 

Some opt for the 929 booster swap if my memory serves me correct

 

I've got a brake porportioning valve, and Wilwood 4-pots in the back that a guy (nofords on here) used to have on his race car out here.
He ran it with a bigger Wilwood Master Cylinder and a TII brake booster, but I didn't think I'd need to use it.

Thanks for the input guys! I think I'll stick with the stock booster for now.

 

What diameter and thickness are the rear rotors? What size are the pistons? Pics?

Why did he upgrade the rears? Was there an issue, or was he just looking to prevent one?

Parking brake?

Most off-the-shelf aftermarket 4-pot calipers have very large bores. This will mean a lot of brake torque in the rear, so you'll definitely need to tune in the bias with your prop valve. If the rear pistons are significantly larger, you may have insufficient volume / excessive pedal travel with the OEM MC and its small bores. Have you talked to nofords about why he upgraded the MC?

BTW -- mine worked OK because I got semi-custom 4-pot front calipers, with small bores sized specifically to work with the OEM MC and maintain proper balance with the OEM rear brakes, with the OEM prop valve (mine have even smaller bores than those in TII calipers, which are 36mm, if memory serves).

 

I'm running the FB booster and MC (one for a GSL) on mine and it's been working very well. I've thought about going with the 929 setup like a few FC guys have done, but honestly I really have no need to at this point - very happy with the pedal feel.

 

Respeed kit front/ modified respeed rear so ebrake cable works better (not pleased with how replacememt hook/lever attached to caliper without stock spring... So I rebent stock spring so it still holds shaft into caliper..)... Stock 85 master/booster... Stops great! Stiff pedal, minimal travel.... Feel no need to upgrade anything on brakes now...