AP CP5555 Pot Sizes

[LotusGTR]

Hi, I'm looking at buying a set of these calipers and running either a 355mm x 32mm or 365mm x 34mm rotors on the front of my R32 GTR.

Some questions I'm hoping can be answered.

I've got to replace or repair my current brake master cylinder and can go 1" again or move up to the 17/16" size. To figure this out I'd like to know what the piston sizes are for this (6 pot) caliper. Anyone got that data?

Finally, if anyone has done a similar conversion, what did you do and how were the results? I guess I would like to hear about what BMC you used, overall improvement, feedback on the AP caliper / set up, pedal feel, balance with the OEM rears would be good to hear about.

Thank you.

[Andy W]

contact AP direct
AP Racing Competition Car Products
Their Tec dept will help i'm sure

[matt j]

Originally Posted by Andy W

contact AP direct
AP Racing Competition Car Products
Their Tec dept will help i'm sure

They'll help you on everything but the BMC as it's not part of 'their' system in their eyes.

Originally Posted by Pete Collen APRacing

Matt

It sounds like an actuation problem i.e. M/cylinder or anti lock, but I can’t throw any light on that though being Nissan parts, you’ll need to talk to the specialists?

I believe your front kit was part # CP5555T1000

There is a lager kit and you could up grade your existing kit by fitting the larger disc & bell assys (approx £850). But it won’t solve your problem, It sounds like your lacking clamping force from low brake line pressures.

So that you can test the line pressures at the business end of the brakes i.e. the calipers. I will send you an analogue pressure gauge that you can screw into a caliper bleed screw port.

To perform the test, run the engine so that the power braking / anti lock system are operating. Apply pedal load progressively until the driver believes maximum load has been achieved i.e. emergency braking. A second person needs to record the pressure gauge readings. You should see at least 1500 to 2000psi on the front with probably only 2/3rds this on the rear due to the front brake bias.

We don’t do a cylinder for the Nissan installation; this would be a Skyline only part.

Pete

pete.collen@apracing.co.uk

Hope that may save you some time and effort.