what size master cylinder is best with the alloy brembo/ M-caliper rear set up?

[jmz]

As I start assembling my SWB with the alloy brembos up front and the M-Calipers out back I wondering if I should move to a 23 master cylinder or if 19 is OK?

Thanks in advance.

Jay

[skinnerd]

Crazy no one has responded to you....
I'd give PMB Performance a call. They know Porsche brakes.

[jmz]

Crazy no one has responded to you....
I'd give PMB Performance a call. They know Porsche brakes.

...yep, Eric will know. I bought the rotors from him and he did the machine work on the m calipers to use on the rear.

[swb911]

The Brembo Alloy caliper has the same diameter 48mm piston as the original front M Caliper. S Caliper and A Caliper.

The rear calipers fitted to a SWB car are normally designated an L Caliper and depending on the model they have either a 35mm diameter piston (narrow caliper - solid disc) or a 38mm piston fitted to the wider S caliper with a vented disc and have 2.25" mounting centres.

If you have fitted an M Caliper using a modified caliper and a radial mount you will probably have a 38mm piston.

If you fit a 23mm diameter Master Cylinder you will end up with a terrible brake pedal feel.

The force you will need to apply for a given braking effort will double and the travel needed will reduce by 50% so it will become very difficult to modulate braking.

The pedal will just be very hard and lack any feel so it will be difficult to assess when the brakes will lock

As you will be using the same size pistons as the standard car the 19mm cylinder should work well.

I am not sure where the idea that a 23mm cylinder is an 'upgrade' originated from but IMHO it just isn't true.

[jmz]

Thanks for the reply @swb911. ...First post?

Cheers.