master cylinder bore size

[dr1ft-pig]

hey all

I'm buying a willwood floormounted brake and clutch pedal kit, i will be running a line from each master cylinder on the brakes (front and rear) to the original bias block on the 86,

my question is what size master cylinder bore should i be using as there is a few variants

and also could someone confirm if the way i plan to set it up will work???

looking at johnny rochester for this one

thanks guys

[federal]

what size brakes are you running? this will ultimately give the answer...

in my car:

FC3S Conversion Front
RT142 Disc Conversion Rear

With No Booster i will be running a 15/16th, with a booster i would run a 1inch...

remeber when you remove your booster ( as you will when using a floor mounted pedal box ) you need to go with a smaller master cylinder bore than if you still had the booster...

EDIT: Spelling

[charged]

Are you running a dual master setup or a single ? I run a 15/16, no booster with willwod dynalite 4piston caliper with 1.75in pistons, rear runs through a adjustable wilwood bias valve running single piston Mazda RX7 sr 2 calipers... works a treat
If your running a dual master setup... 3/4 will be plenty for the front and a 5/8 to the rear, nephew runs this setup with mazda 4 spot calipers and same rears as mine. He runs no hyraulic bias but the screw/cable type that runs to the pedal and adjusts the balance bar

[dr1ft-pig]

I'm running ra60 fronts and kouki t series drum rear

with the floor mount setup ill be using 2 master cylinders for the brakes 1 front and 1 rear obviously

will that make any difference to cylinder size as to using 2 masters instead of one???

atm I'm using stock master mounted straight on firewall without booster and brakes are shite

would 15/16ths be appropriate in my situation???

EDIT: reply to charged

as said above ill be running dual master cylinders, but i want to use the stock bias block as brakes are very close to stock

so would running same size mc front and rear be appropriate???

cheers

[federal]

to work out the correct master cylinder sizes you need to know the size of the pistons, and obviously the amount

[dr1ft-pig]

got no idea how big the pistons are

i run stock kouki drum rear so stock brake cylinders

and up front is ra60 gear which is basically the same as JDM 86 gear

[charged]

yeah need to know the sizes of the drum wheel cylinders, I would actually put the money towards a rear disc set up rather than floor mounted dual cylinder pedal box, it will be a much better performance upgrade than the pedal box... the pedal box can be adapted later for better balance. I you do convert to rear discs the residual pressure valve will need to be removed and also there may be one in the master cylinder. Its a rubber type valve with a spring to hold residual pressure for drum brakes.

[dr1ft-pig]

i just went from a disk to a drum for better handbrake

i need floormount and in cabin masters as my the engine i run just fits and the plenum hits the master cyl thats mounted on the firewall without booster


I'm doing this mod for clearance, the performance of it is just a bonus

[federal]

quick thought....

convert the drum rear with corona discs....then you will have the better handbrake along with disc rear....

[dr1ft-pig]

how do you mean better hand brake??? do the have the disk/ inner drum for handbrake setup???

they basically bolt up yeah???


i need to upgrade to an f series rear end soon as the t series just doesnt hold up to what i wanna give it for long enough, and ill be chasing another 50-100hpatw soon so ill be probably converting to twin caliper setup once that is done