how do i work out Wilwood piston sizes??

[ae86racer39]

Wanting to put a set of Wilwood 4 pots on the front of my AE86, but want to retain the std m/cyl. How do i work out what size calipers i need to meet this need, i.e piston size??

[KinLoud]

Not quite sure why you might want to do this? Show? Better braking?
Show - fair enough.
Better braking - before you have got to the stage of having to upgrade your calipers, I presume you have upgraded pads, changed disk diameter/thickness, better brake fluid. What problems are you experiencing? Uneven pad wear (tapering), brake fade, overheating? Have you considered a brake bias valve to reset the bias if you don't get the size pistons/piston area you want?
Also0 think about finding a bigger diameter brake master that will handle a greater caliper piston area without having too much pedal travel?

Well if you want to spend lots of money for the hell of it...

Measure the diameter of the standard AE86 front caliper piston = D .
Divide D by 2 to get the radius = R .
Multiply this by itself i.e. RxR = R squared
Then multiply R squared by 3.142 (PI) = Area
This will give you the area of your AE86 pistions.

Do the same thing for the pistons in one Wilwood caliper (each piston individually then add them together). This will give you the piston area of the Wilwood pistons. If the area is different from the AE86 piston area then go for a caliper for with smaller or bigger pistons and work out the area again until you get the same area.
This will tell you what caliper to use with the standard brake master.

NOTE - make sure you use the same units - don't mix mm and inches as this will make your brain hurt!

Ken
Ham
021 408 863

[ae86racer39]

Kinloud thanks for your response, now i'll just have to do the math and see if what i got will work!!
Better braking is what im after, to get rid of fade as my 86 is a full blown dedicated circuit car(not road legal)
Yes i am currently running carbon metallic pads, Motul RBF600 brake fluid, brand new rotors, cooling ducts etc,but hopefully a 300mm 4 pot setup will give me a little edge on others under brakes!!

[GT4 20]

Why not fit a pedal box? That way you can get a master cylinder to suit.

On my Rover (which is being turned into a tarmac rally car), I'm going to be fitting 331.7mm rotors with Wilwood 6 pots up front and 300mm with twin pots at the rear and am using a huge Wilwood master cylinder -

Even that will only just cope
Gary