[V8Vairs] Hydraulic Clutch Question

[Jim Acker]

Stepping to a 5/8" bore will make a big difference in pedal effort.  You can
calculate how much stroke you will lose if you know the stroke of your
master.  Measure how far the slave moves when you have the pedal all the way
to the floor with the .75 master.  Lets say the slave moved 1.5" and the
master stroke is 1.25".
 
Here is the math for the volume:
 
A cylinder with radius r units and height h units has a volume of V cubic
units given by 

 Volume=pi X radius squared X height

So, our master is 3.142" X .141" X 1.25" = .601"
 
If you switch to a .625" bore with the same stroke, then 3.142" X .098" X
1.25" = .385"
 
Now that we know the volume, you can do a proportional calculation to
determine what happens to the slave.
 
.601           .385
____   =     ____     
 
1.50            X
 
.601x = .385 X 1.50
.601x = .578
x = .5775 / .601
x = .961
 
So, if you dropped from a .75 master to a .625, assuming your slave moved
1.5 and all other things constant, you slave would now move .961".
Since precision isn't too important here, you could just say that assuming
the .625 master has the same stroke as the .750, you will drop your slave
stroke by about 36%.
 
Jim