My bug with 2.4 type 4

[Wally]

Originally Posted by evilC

The front brakes will be 4 piston and the rear is shown as a single piston. A bug requires near to a 50/50 brake bias. That is to say that the braking power should be about the same front and rear because of the heavy rear weight bias transfers forward under braking. On a front engined car with a weight bias of 55% front and 45% rear the brake bias will be around 75% front and 25% rear to take care of the weight transfer under braking.

The way to calculate your current bias is to compare the total front caliper piston area/front master cylinder piston area with the total rear caliper piston area/rear master piston area. Also, the brake disc diameters will moderate the final figures but I am assuming that the front and rear discs are about the same diameter?

You say that the master cylinder is larger - why? The smaller the master cylinder the more power you can apply to the brakes as the hydraulic advantage = total caliper piston area/master piston area. The downside of the smaller master piston is the longer pedal travel but generally this is minimal on a well set system. The bug 19/19 master cylinder is usually big enough for almost all applications and it will be only where massive caliper piston areas are used will you need a larger master cylinder to compensate.

Clive

All of the above is VERY true. Took me a while to actually get to know the real world data against the 'theory'. The theory is rather off, but the above is spot on.
Just take really good notice of what he said Roel ;-)