Hey Ron
Nice progress.
Here is what I have come up with messing with my twin master set up for years. I am at .70 for the front and 3/4 for the rear. Running the Wilwood stuff (6 piston front 4 piston rear)and the sizing for my caliper piston area is about the same as a C5/C6 vette. My pedal ratio is 6:1. Caliper pressure gauges show 1200 psi front and 900 psi rear with about 100 lbs of leg pressure. I started at 7/8 in the front and 1 inch in the rear and could barely get my car to stop.
As Greg stated, the larger the bore the more fluid volume. I would have a higher pedal ratio (7:1) if I could have made it fit and run a slightlly larger bore size.The problem that I have run into is the masters are so small to help the pedal effort and to be able to lock the wheels, I do not have much fluid volume and you can really tell the pad knock back. If I were running power brakes with a large volume master (1 3/16), it would hide the knockback that I am getting now.
The balance bar is for fine tuning and you will need to try and size the masters as to run the balance bar as close to the center as possible. Then use the adjustment to fine tune or change for conditions. IE autocross, more rear brake, speed stop less. Reason for the larger master in the rear is for fluid volume and for the same given pedal effort there will be less force applied to the rear. Also, the rear caliper piston area is normally smaller than the front and will require less pressure.
Getting the corrrect pads will make the most difference in your stopping power. I was running Wilwood BP 10's and could not lock them up when cold. Swithed to a high bite autocross pad and it was like night and day. While trying to find the right brake compound I tried a full race pad, way too much for a street tire. I went to bed them in on the interstate, running 85 mph I hammered the brakes to start the heat cycle...front tires locked up. I was suprised to say the least.
That is a pretty racing looking set-up you have going there. Good luck with getting it dialed in. I would not run the same size master front and rear.
|