My bug with 2.4 type 4

[RuleO9]

The diameter is the same.. You're the first to say that the brake bias isn't correct with these calipers..
So i need? Bigger rear calipers or smaller had the front?

[evilC]

You do need the same piston area or thereabouts at the front and rear if you are running a plain bore master cylinder. Alternatively, you could use a balance bar set up on the brakes so that you can run the same calipers as you have but i suspect that the difference in the master cylinder bores would be almost unobtainable. Another problem you have is that the rear disc is solid that restricts your options on calipers dramatically. You were much better off using the 944 rear disc as many of the standard Porsche alloy calipers fit. I have the 944 set up with 928S4 4 pot calipers on the rear that would complement your front set up perfectly.

I suspect the Kersher rear brakes were to match the standard disc fronts not a Porsche 4 pot units. If you want to retain some sensible brake balance you will need in my opinion to change the rear discs and calipers for a Porsche set up with 4 pot calipers. Obviously, if you can fit the same set up to the rear that you have as the front that would be ideal. I would (have) fitted a brake bias valve in the rear circuit when you have matching front and rear or more powerful rear brakes so that you can finely balance the car. For a road car the front brakes must just lock before the rear to maintain optimum control and maximum braking effort.

Clive