Why did they change from the six piston brakes (05-07) to a four piston brake (08-09)?
most likely it was a cost issue..
A six pot caliper takes more fluid to move the same amount as a 4 pot caliper. Less fluid means more clamping force with less lever movement.
I don't think that is quite how it works. People perceive brakes to be powerfull when they don't have to pull hard on the lever to get good braking. You get that either with greater force multiplication in the hydraulic system, or getting brake pads with greater coefficient of friction. The force multiplication in the hydraulic system depends on the master cylinder area and displacement, and the brake piston area.
If anyone has the parameters for gen1 and gen2 busas I would love to have them.
Now when brake fade is considerer, bigger is better.
The 4 pot system does require less fluid movement than the 6 pot system to apply a equal amount of pressure to the pads and rotors...now if you were to use the same master (which they do) for the 6 pot system on the 4 pot system...you will have more pressure on the pistons to squeeze the pads and rotors. The Gen2 also uses a radial mount for the calipers which is more rigid than the Gen1 design...
The 6 pot system sucks and takes a lot of fluid (volume) to work well...the 4 pot calipers are more efficient and do the job
The Gen2 also uses 310mm rotors vs. the 320's on the Gen1...Gen2's have better bite and noticeably stronger brakes
Well I took the gen1 and gen2 service manuals so i can lay some hard facts on your
Gen1 has 15.854mm master cylinder diameter, gen2 has 13.984mm
Gen1 has 26.970mm brake caliper piston diameter, gen2 has 32.130mm
From these we can deduce the force multiplication:
gen1: 12*26.970^2/15.854^2=35
gen2: 8*32.130^2/13.984^2=42
So yes gen2 has 21% higher force multiplication
Putting gen2 master cylinder onto gen1 would yield 29% improvement in braking 2
Well I took the gen1 and gen2 service manuals so i can lay some hard facts on your
Gen1 has 15.854mm master cylinder diameter, gen2 has 13.984mm
Gen1 has 26.970mm brake caliper piston diameter, gen2 has 32.130mm
From these we can deduce the force multiplication:
gen1: 12*26.970^2/15.854^2=35
gen2: 8*32.130^2/13.984^2=42
So yes gen2 has 21% higher force multiplication
Putting gen2 master cylinder onto gen1 would yield 29% improvement in braking 2