Quote:
Originally Posted by T77911S
the tilton video mentioned the SMALLER MC for the front brakes. I had mine connected with the bigger MC to the fronts as I am 99% sure that is how it was when I replaced the 2 MC's. BTW, one is 1 inch and the other is 7/8.
so I got to reading about brakes, again.
just to make sure I understand.
the smaller dia MC provides more FORCE so it goes to the fronts.
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Hard to generalize whether you need the larger M/C on the front or rear circuit, because it depends on both caliper piston area(s) and rotor diameter(s) front & rear - and what target bias is "right" for the car and how it'll be used.
The piston area of the smaller diameter M/C generates higher line pressures for a given amount of movement - but moves less fluid. More/larger caliper pistons have more area, thus need more fluid moved. Larger diameter rotors make more torque. The ratio between the master cylinder area(s) and the caliper pistons determine how much pedal movement results - and the size of the master cylinder(s) determine how much force is needed to generate the required line pressure to stop.
See, it's easy, right?
Most conventional setups would use a smaller M/C for the front. 911's pre 3.2 had caliper piston sizes that provided a natural balance front/rear - so used tandem M/Cs with same size for both circuits, and would want equal-sized M/C in a dual-master setup.
Some very specific scenarios want the exact opposite to "normal" - like fitting 996 brakes to a G-body and correcting for the resulting excessive front-bias. Then you might use 7/10" front 5/8" rear for the N/A variants, or 3/4" front 5/8" rear for the TTs. YMMV.
1" M/C is pretty big; for example, would result in little pedal movement/high pedal effort on 911's, unless using 6 pot Cayenne/GT3 calipers or something. SCRS used 930 brakes and a pair of 5/8" M/Cs.
On a race car which could have literally almost anything fitted? Probably should do the math/research what bias ratio etc is the ballpark.
But just based on the rears locking up and how "most" conventional setups would use smaller M/C on the fronts, it does sound like you might want them hooked up the other way round...