Wilwood brake bias

[Blue Viking]

I am going with the Wilwood brakes for the Roadster. The calipers are 6 piston in the front and 4 piston in the rear. I am installing a hydroboost setup, so i will not be using the balance bar to set brake bias. Has anyone tried a similar setup? I am curious as to whether the 4 vs 6 piston setup will provide a good bias for the brakes as is, or if i need to Install a pressure reducer for the rear brakes.

[Gordon Levy]

I would not recommend a hydroboost with big brakes. It's pretty much an ether or. Our 6piston/4 piston with matching master cylinder and adjustable prop valve will have the car stopping great with little to moderate pedal. Hydroboost will turn them into an on/off switch.

[Blue Viking]

Yeah I'm well aware of that issue. I'm pretty much committed now as I've had the pedal box modified for the hydroboost setup. I will see how it feels when I'm done. If it's too much I can probably modulate the pressure going to the hydroboost unit to reduce the brake assistance somewhat. So I take it you've had to use the prop valve to achieve proper bias?

[Gordon Levy]

Yes, an adjustable prop valve on the rears is required with a 4 piston set up. The adjustable fluid valve that are made for this type of thing can help but be aware of how much your adjusting it back. It increases the back pressure load on the pump and can burn it up.

[TrevorP]

I have gordon's 6/4 wilwood setup on my race cobra with the wilwood master cylinders. The braking capability is insane. I can come down from 165 to 50 in within 2 markers at the end of the VIR straight. I couldn't imagine these brakes would work with a booster. They are designed to be non-boosted. The pedal feel is incredible.

[tonywy]

I have Wilwood 4 piston set up front and rear manual non boosted. Braking is marginal at best. I am not using the Wilwood pedal box. I am thinking of trying a more aggressive pad or should I try a manual proportioning valve. Any suggestions?

[Gordon Levy]

Tony, what master cylinder are you using? What rear brakes? Has your brake pedal been modified?

[tonywy]

Not sure what master cylinder, it appears to be a typical cast master. I bought this car. The rears are Wilwood 4 piston like the front drilled and slotted rotors as well. How do you tell if the brake pedal is modified? It appears to be a donor assy.

[Gordon Levy]

You need to measure from the push rod to the pivot on the pedal. If it is 3" it's unmodified. If it's 1.5" and mounted in a lower hole in the pedal assy it is modified. I have a bolt in master that would help you a ton if the pedal mod is done. If the mod is not done it take some effort to do the mod and reinstall the pedal. Give me a call sometime and we can talk at length.

[tonywy]

That's great info , Thank You ! Will check this out and get back to you.