master cylinder for stock front disc + empi rear discs

[mabbo]

thanks for the replys guys

well, im not 100% sure that the bug caliper has 2x 40mm pistons, im sure i read that online somewhere.

im quite suprised how front biased the brakes are with the stock front vw disc/caliper setup and a empi rear kit. when i couldnt get a firm pedal with my stock duel circuit master cylinder i thought it must be the problem because empi wouldnt sell so many rear disc kits if they havent been designed to work on a near to stock bug... guess i was wrong.

so, to improve the bias, im going to have to improve my rear calipers... again?

i thought the early 944 rear calipers also had 36mm sliding calipers on the back, with big (54mm?) sliding calipers on the front? so the rear 944 caliper and rear empi caliper are v.similar? what if i upgraded my front calipers to something bigger? maybe a 4 piston wilwood or something then keep the 944 master cylinder?

sorry if that goes against what you have just said - im really not all that clued up on brakes or braking systems - hence my posts

mabbo

[evilC]

Yes, the Empi 36mm single pot rear is very similar to the 944 rear that is also 36mm single pot. Simply transposing the 944 set up into a bug is not the way to go as the 944 is a heavy front engined car that needs a strong front brake bias. Even though it is reasonably balanced front to rear ~50/50 with the rear transaxle, under braking there is a substantial weight transfer, needing all the effort to the front. The bug however, is tail heavy ~37/63 and requires a 50/50 braking bias. Originally the 944 had a 19/19 m/c that gave a front bias of 68.75/31.25 but this was later moderated back to 59/41 with the stepped 23/19 m/c.
To make life simple for you to select your brake package lets assume that the ideal brake bias for the bug is still 50/50 then:
Total Front Piston Area/master cylinder piston area = Total Rear Piston Area/master cylinder piston area.
As previously said, if the rear is larger than the front then that is easy to deal with by incorporating a pressure limiting valve in the rear line.

evilC