Caliper cup sizes?

[260DET]

With a 15/16" master cylinder, for competition use, adjustable bias, four spots in the front and singles at the arsend. What size caliper cups should be used?

[RBMATT]

SORRY can you explain what you want again.You say you have all the goodies what do you mean by caliper cup sizes.Maybe its me:knock:

[260DET]

When choosing the calipers, what size cup/piston ones would be most suitable to match a 15/16" MC?

I'm dyslexic sometimes :D

[dattoman1000]

I'll take a guess
Since there not enough info to really give the correct answer
1 5/8" + 1 1/2" front (staggered piston sizes)
1 5/8" rear

[260DET]

Thought I'd catch you before you headed off DM, what more info?

[Datman]

I read cup sizes and clicked on the thread straight way! How disappointed I was.

Anyway...Aim for at least a C-Cup Richard...don't settle for anything less!

[dattoman1000]

ok........
Pedal ratio ?
Wheel/tyre size ?
Boosted or non boosted ?
Disc diameter front ?
Disc diameter rear ?

Do you have any calipers fitted to the vehicle yet ?..... front or rear ? if so what size pistons are they now ?
Your adjustable bias is just a valve in the rear circuit ?

That will get me started

I guess it really depends on what brand you want to use for which caliper to buy

[Dexter]

The master cylinder is usually one of the last things you fit to the brake system to match the fluid displacement from a normal brake application.
The fluid displacement controls the master cylinder push rod travel which multiplies by the pedal ratio to give you your pedal travel.
Most vehicles have between 4 and 6 to 1 pedal ratio.

15/16" M/C = 0.690 sq in or 4.453 sq cm
Now add up the piston area on 2 x 4 pots and 2 x 1 pot calipers, multiply by 0.25mm travel each.

Most 4 pot calipers have 36/40 or 40.6/40.6 or similar pistons and rears are usually 36mm to 40mm on single or twin piston versions.

36/40 = 22.754 sq cm
36 rear = 10.183 sq cm

2 x Fr + 2 rear = 65.874 sq cm / (M/C) 4.453 sq cm = 14.793

14.793 x 0.25mm calier piston travel = 3.7 mm M/Cylinder travel
3.7 mm M/C travel x pedal ratio (4:1) = 14.8 mm pedal travel

15 mm pedal travel to engage the pads + take up in linkage + fire wall flex + caliper flex, ECT. It's not bad but could be better.

I wouldn't go any bigger in caliper piston size without a larger M/C.

[260DET]

Its for the 280ZX (avatar car) and I'd like to keep the stock MC and booster. The suspension, hubs etc will be all S14 though. Planning on 17" wheels and ~330mm rotors, put the adjustable bias on the rear brake circuit with the 260Z which seems to work well.

The rear calipers will have to have a handbrake, open to suggestions there. From a US source the stiffest Wilwood calipers are the narrow mount Dynalite so probably them for the front.

[dattoman1000]

Dynalite is too small
Superlite is the way to go if you insist on using the US caliper
I'd look at these if I was you http://www.wilwood.com/Products/001-Calipers/009-SL4R14/index.asp
They have dust boots too
Only thing is they don't have the most desirable piston sizes
I would take the 35mm pistons over the 44.5mm ones
If they did one inbetween with around 38-40mm that would be ideal