After you pump up the brakes, does the pedal remain hard, or does it slowly go to the floor? If the pedal remains hard, I would say your master cyl. is not moving enough fluid. Those 16 pistons have a lot of area, so the master cylinder will need to move a lot of fluid when you stomp the whoa peddle. If you dont already have one, I would install a proportioning valve, or an adjustable bias valve.
suicidebomb