Brake Master Cylinder Sizes
Turbo Mini Forums

Chaps and Chappaties

I've been pondering over the size of cylinder I should go for. As im using a BIAS Bar setup, im thinking of using a smaller cylinder?

When I ran .75 for both front and back, the pedal seemed very heavy.

So in theory a smaller bore will give me more pedal travel but more pressure? Is this right??

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Smaller bore will give higher brake fluid pressure.
you are spot on

If i have more toys than you when i die, I WIN

I wonder if .50 is too small?

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Have you not changed the calipers though? Master cylinder to caliper needs to stay in a similar ratio as before.

Remember the cylinder/caliper on the other end of the bake pipe will have an effect too

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Good point, rear calipers are 4 pots and front are 6 pots.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

So if I measure each piston on the calipers and add them together. What should the Ratio be?

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

My god just read a calculator table.

Nose Bleeds occurred.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Ideally you would measure old calipers and master cyl. For each calculate area by using pi x radius^2 then work out your old ratio as a starting point.
Then measure new calipers and calculate area on those. Then using your ratio from the old setup work out a master cylinder size to start off with. From there you can then juggle it by changing cylinders if you need to. Be wary if going too small it can give a very long pedal. To big can give a very hard pedal. So it's very much a balancing act.

+1 with Tom. When I did the fiesta setup I did check against the standard mini setup because I was worried about the large single piston.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Not sure if it'll help you but i use a .625 on the front and a .75 on the back on my wilwood dual bias. Set it up with pretty much all on the front with not to much pedal effort.

KAD 4 pots and normal mini cylinders on the back.