Quote:
Originally Posted by Turbo86
So are the performance package calipers the exact same as the STI calipers? If it takes the same size pads and rotors, and looks the same from the outside, is it pretty much the same thing?
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The STI brembos have a pair of 40mm pistons and 46mm pistons. The smaller pistons are what the rotor "sees" first as there is a slight force wedging the pads together. Except that the sti mounts the calipers on the back of the upright and the brz has them on the front. So to keep the bleed screws and internal passages in the right place you would have to swap them from left to right, which puts the pistons in the wrong order.
My understanding is that the BRZ PP calipers have 40mm pistons and no differential bores. The subaru 4-pots and stock brakes have all the same sized pistons and it's not the end of the world but it would have been nice if they'd done 40/42 or something.
So the total piston area is smaller to maintain correct bias with the bigger rotors (sti brakes move it forward), and the smaller area also results in a firmer brake pedal. The sti calipers meanwhile have more piston area and a bigger rotor and they don't work on the brz.