4 piston brembos, Master cylinder, proportioning valve confusion.

Kern Dog said
Uhhh....

UNboosted master cylinders are often a poor choice for a 4 wheel disc arrangement because the calipers need more force than the driver can provide. The booster makes it possible.
I have tried 4 different master cylinder sizes when I've tried to make a manual MC work with 4 wheel discs. All of them gave an hard pedal with far too little braking force. I just couldn't press the pedal hard enough to slow the car in a rapid and safe manner.
Also, 4 wheel disc systems should NOT need a proportioning valve. The caliper piston count and sizing is what should determine the proportioning.
You want the fronts to have double the surface area of the rear. In short, a 2 to 1 ratio in brake force front to rear.

When I spoke to dr diff he did say the valve was necessarily needed. But more based off application. Considering what you’re saying. And considering I’m using front and rear calipers off the same car, they should function properly with no proportioning valve needed, as long as the master cylinder and such all have big enough bore. So perhaps I’m better off hooking it up with out the proportioning valve and going from there. I was also thinking it’s only another $65 in the grand scheme of things so to just put one in just for the sake of not re doing things, even if I don’t need to adjust anything atleast it’s there incase I do