Great find @
eikond!
I have some questions though, since
my Google-fu is terrible right now:
*Aren't the stock front calipers 2-piston sliders with 42.8mm pistons?
*Your Z32 TT's are fixed calipers with 4x 40.4mm pistons?
If that's all true, then the piston areas are 2,877mm^2 and 5,128mm^2 respectively. That would be a massive front-bias movement. Sorry @
Dave-ROR, your equal and opposite reaction idea isn't a perpetual machine that creates magi-double piston area in the formula. There's a fixed amount of piston area, and thus force, for any particular caliper, regardless of it's piston amount and orientation.
Now, what's happened here is since there's so much more front piston area, the master cylinder requires much more pedal travel to get the same line pressure. Chances are the car now has a longer and softer pedal. The pad mu is totally unknown and of course impacts brake torque significantly.
Using
Legacy777's spreadsheet, the rotor diameter change is resulting in about a 5% front bias change.
That would all add up to a huge front bias increase. I don't feel like calculating it right now, plus without knowing the pad mu's it's fruitless.
If I were tackling this from scratch I'd want to find a front caliper with smaller pistons, but for $600, an inch more rotor diameter and 6mm more thickness, on top of EBD that everyone has seemed to forget about, this is probably a decent DIY solution even for light track use.
Bravo!
