I am in the process of completing the build of a BMW E30 325i racecar, based on a shell from a 1990 316i non-ABS model. The car will remain non-ABS, so I have purchased a new ATE brake master cylinder BMW part number 34311154405.
This master cylinder has three ports, with two of the ports at the far end (furthest from the firewall) and the single port closer to the servo (see pic). The two ports facing horizontally have small holes, about 2mm dia, for fluid to pass through. The single port at the end facing downwards has a larger hole, about 4mm dia, for fluid to pass through. I have assumed that the two ports at the end, next to each other, could not be for the front brakes since one has a larger hole for the fluid. Presumably, this means that the circuit comprises split front brakes and a single line for the rears.
Can anyone confirm that this is correct?
Also, that would mean that this MC must have a single straight diameter bore. Correct?