I'm with ricola. Sliding calipers need big time volume. I've done 944T setups with stock MC, no problems. (Just a random fact, almost all Porsche 4 piston calipers use the same piston sizes, 944T, 993, 996, 986 etc). It's a matter of caliper efficiency. For example, if everything is in top shape on a 4 piston caliper, the piston only retracts
.005-0.010", which technically speaking is 'sh!t-all'. So when you get on the pedal, it doesn't take much volume to push the piston to push the pad to engage the rotor.
A sliding caliper is another beast. I believe that your front calipers have a 54mm piston. That's the same as a 944NA. The 944NA need a 23/24mm MC piston to get the caliper moving with a decent pedal. See where I'm going here?
You said:
"pedal is firm but firms up even more on pumping".
When you keep pumping you are keeping the piston extended, hence a taller pedal. As soon as the piston retracts, it takes more than one stroke of the MC to get the pedal back.
I say drop the 944MC in. Good luck and keep up posted, we can all gain from your experience.
BTW: I've added a little more on my site regarding MC's, since it's a FAQ.
http://www.vdubengineering.com/techn...onversions.htm
Scroll down to the bottom of the page.
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