1965 911 caliper upgrades for FIA race car project - help needed

[redrobin911]

HI

I'm building a FIA '65 911 and want to know what the correct brake calipers I should be using - and from what porsche they came from?

Front calipers
the std caliper has a 3" bolt spacing with a pad size of 62mm x 42mm but the homologation regulations allow for 77mm x 54mm -piston size of 48mm in both cases. I have an ATE caliper that fits this spec but it seems to be branded BMW? did ATE make a calpier this size for Porsche?

Rear calipers
the standard caliper has a 2 1/4" bolt spacing with a pad size of 55mm x 37mm - homologation allows for 62mm x 42mm - piston size seems to be 35mm but there is a reference to 38mm.

The pad size for the upgraded rear calipers is the same as the smaller (original) fronts but wont fit because of the bolt spacing!

Any ideas / help would be appreciated.

[Neunelfer]

Fronts - That is a BMW caliper however, it should simply be branded ATE with no BMW markings on it. It depends on how you want to play the came. If it's "by the rules" then bolt them on. No Porsche ever came with these calipers.

Here's a set we sold a couple weeks ago:


Rears - This is a tough one. There's a variety of ATE calipers with 38mm pistons and the 2 1/4" spacing. I've yet to find one that takes the larger AP31 (62mm x 42mm) pad size. AlanUK here has a vented rotor kit based upon an ATE caliper as such but, I believe it has the smaller AP30 pad size (same as your stock L-Caliper, wide L-Caliper and 914-4 rear caliper). Alfa 105 cars use a variety of the 2 1/4" calipers with everything from a 30mm piston to a 38mm piston... again, pad size remains small.

Wide L-Calipers (shown below) or Alfa calipers (similar but without the compensating line) may be the only choice. ATE may not have put that large a pad on the 2 1/4" mounts... We recently built a pair of Wide L-Calipers for a customer who wanted the 38mm pistons for a rally car. They requested we remove the spacers so they could comply with the solid rotor rules.

[davep]

Just to add a little to what Eric has stated, the caliper type (L / M / S) pretty much designates the pad size. The M calipers come in many piston sizes and configurations, but all take the same pad size (although pad thickness and pin holes can change). For example, there are spaced (for vented rotor) and non-spaced versions, 48mm (front), 38mm (rear) and 42mm (914 front) piston sizes, and a variety of inlet configurations. The two 914 front caliper versions are not fully interchangeable, the later version takes a thicker pad. The 914/6 rear caliper has the parking brake mechanism built in, and the pad pin holes are two different sizes.