I hate the brake booster. Because of the cams in my car, I get really inconsistent braking when blipping down through the gears... I can actually feel the assist coming and going, and beside that, the pedal feels numb.
So I ran the last few events to test the brakes with the booster line removed and whilst the brake pedal requires lots more force, the brake pedal is far more linear and I can feel the brakes working through the pedal. Once used to the additional pressure required, brake modulation is far better. I immediately found that I could brake later and deeper into the corners and my times dropped a bit.
I've pulled out the pedal box and removed the booster entirely. As part of doing this I figured I may as well go for an adjustable bias and dual masters. Here are some pics of my pedal box mod:
Some additional bracing is required on the pedal box to strengthen it after being modified. I've sized the master cylinders at 5/8" for the front, 0.7" for the rear so they are slightly smaller than the stock dual master from my car which was 7/8" will give me some extra brake ratio. Initially I'm keeping the stock pedal ratio of 4:1 but will probably need to increase this to 5:1 - 6:1 by dropping the top pivot a little. We'll see how it feels once it's in the car. With the booster still present but the vacuum line remove, there is a lot of resistance the pedal box adds, so maybe with it gone it might be fine.
So far the mods have been extremely simple, retaining the original mounting points on the pedal box. The biggest hassle is getting all the brake lines connected which I'm going to do via a single custom distribution box that will have 1/8" ports in, 1/8" ports for brake sensors and 1/8" ports out for the various lines.
I'll report back in a few weeks when I've raced with this setup.