MTR

The ratios that Bill is quoting are a functions of the total piston area of each caliper. It's a simple area of a circle equation Area = Pi * r^2. For example:

Front 4 piston (36 and 40mm): 3.14 * 18^2 + 3.14 * 20^2 = 2273 mm^2 of area
Rear 2 piston (44mm): 3.14 * 22^2 = 1520 mm^2 of area
Rear 4 piston (28 and 30mm): 3.14 * 14^2 + 3.14 * 15^2 = 1322 mm^2 of area

You can divide the front area by the rear to get the respective 1.496 and 1.720 ratios. So the more hydraulic force you can apply over a larger area the more brake torque you can generate. Therefore since the 2 piston has a larger area it can generate more brake torque, but it will overheat quicker and not last as long as the larger pads found in the 4 piston caliper - hence why it's not really "better" even though it's hydraulically superior.

The proportioning valve reduces the pressure and therefore braking torque of the rear calipers once the driver has applied over the "knee" pressure of either 45 or 55 bar. This causes the brake bias to significantly shift to the front calipers causing them to be overworked and the rears to be underutilized.

Make sense?

sml

And the noise ... On the road, the RS29 was loud enough that I seriously considered wearing ear plugs. It was pretty ridiculous.

Fine on the track of course.

freno a mano

Thank you for the explanation, it's now clear

Bill Verburg

Here's a survey of various 964/993 brakes setups, I have 993RS on both my cars one w/ a p/v and one w/o either is fine when the car is set up right, thru '83 a 911 had a f/r torque ration of ~1.491 w/ no p/v, due to the legal environment in much of the worls porsche has gone to much more conservative ratios on newer cars used on the street



here are few of the newer racecar set ups w/ dual masters for further comparison

ThomasC2

I've used RS29 for many years and like them a lot. But since two years ago I switched to Hawk DTC60. Very similiar to RS29, easy to modulate and long lasting. The big flip side is the price level. Much cheaper than pagid.

RSAErick

I'm currently using RS29 Pagid Yellow in front, and Pagid Black in rear. I have no complaints for 'endurance' (DE) work, as they last well; however, I'm considering other options to give better bite and feel. Maybe PFC?

As for the RS29 Yellow squealing? I'd refer to it more as 'howling'. It's truly amazing how loud they can be.

Jason @ Paragon Products

The RS14 will have more bite if you want to put that compound on the front. The new RSL1 compound will also have more bite.