FS: 914 Rear Race Calipers, ***No Handbrake Option*** Options

[Eric_Shea]

Every now and again we get a pair of late 912 rear calipers in-house. These rare calipers share the 38mm piston diameter with the 914-6 and all 911's (for practical purposes) through 1983. These also have the same #31 pad size associated with the 914-6 and 911 calipers. So... larger pistons and larger pad size.

What are these good for? If you've moved to 5-lug up front and you're now using anything from an M-Caliper (stock 914-6), an S-Caliper (911S, RS, 930), an A-Caliper (911SC through 1983) or a Wide A-Caliper (911 Carrera) these would be a bolt on caliper that would retain the braking bias those cars were set up with (48mm pistons up front and 38mm pistons in the rear).

These are true late 912 calipers vs. 911 rear M-Calipers. What's the difference? They don't have the 10mm spacers. They have the same Ribe R6 cap head fasteners just in the shorter length to accomodate the spacerless application. Because there's no spacers, these fit over a solid 914 or 914-6 rotor (keeps weight down). With the 3" mounting ear spacing, these bolt right on to a 914 rear control arm.

***There is no handbrake option if you install these. This is why they are recommended as race calipers only*** You can add a spot caliper or, install the early 911 handbrake assembly to your arms but, these are really a great solution for the track car that needs proper rear bias and a larger pad without worrying about the DMV and their rules and regulations. You'll probably want a 19mm MC as well.

Comes with everything you need (pins springs and bleeders) with the exception of pads (we can help there too...)

Our normal restoration price is $249.00 plus cores. These will sell fo $199.00 for the pair with no core required. Shipping is $9.85 Flat Rate to anywhere in the US. Ask for International shipping. Crappy picture below:

[Eric_Shea]

You can also bias brakes with pad compound. ie: stickier pads up front and not so sticky in the rear... .

That's not a great idea. It takes a LOT of hit or miss and experience with pad compounds to play this game. Dan is the only guy I know that has done this successfully and he races his 914 regularly in wheel to wheel competition. Do me (yourself) a favor, make a quick list of all the brake pads you know of for our 914's. Now list them, in order, from stickier to not so sticky. Ready... go! (IMG:style_emoticons/default/wink.gif)

The question is; why? When the proper caliper with the proper piston size for best biasing, made off the same casting, with the same pad size is available to bolt on to the same mounting location; why put an irregularly large pistoned caliper back there?

With any or all of the calaper combinations you discussed....do any of the combinations ALLOW the removal of the stock... brake bias/brake pressure requlator?...or do to a specific combination,is the B.B. P.requlator... removed to achieve maximum breaking ability?

Not on my car. Removing it does not acheive maximum braking ability.

The pressure regulator is SO WAY MISUNDERSTOOD by the 914 crowd. One day, back when we were smashing rocks together for fire sparks, someone said; "If you take the proportioning valve out you'll have better brakes." I bought into it for a while as well, until I did some further reading. There's a page dedicated to it in the factory manual and it's a great read. The funny thing is, the Alfa boys have the exact same valve and if you cruise posts on their board regarding the subject, they would think you were crazy if you wanted to take this out.

That said; the pressure regulator is not a proportioning valve or a bias valve of any sort so it stands to reason it has a purpose beyond balancing our braking bias (which the factory did extremely well with piston sizes... hence the chatting herein). There are two things that you should read to help you put this together in your own mind. They helped make it click for me and I've never gone back to recommending a "T" fitting or an aftermarket bias valve to anyone ever again. Those two things are:

1. Vic Elfords book on Porsche Handling. There's a section about "mid-Engine" and it touches on 914's. We get all pumped up when we tell others our cars are "mid-engine" and superior to God in handling. Vic points out that they are rather good but, the 924-944-968 package is better because, polar moment inertia can cause our little 914's to spin like a top once they get started. Having the weight at the ends (engine in front, tranny in the rear) is much more predictable and controllable. It's a good book to have and a great read when learning all that you can about your Porsche.

2. The page from the manual explaining what this little bugger really is. As stated before, it's not a proportioning valve or a bias control. It (as you rightfully stated) regulates pressure. It ONLY does this when it experiences a panic stop of 535lbs. of line pressure. It shuts the rear circuit down and slowly brings it back in to prevent the rear wheels from locking up. This keeps as much control as possible in the rear of the car in such an instance (no screaching, locked up tires back there).

Bottom line; the pressure regulator sits there and acts just like a "T" fitting, passing all the fluid you can deliver to the rear calipers unless there's an emergency where they may lock up. Then it springs into action.

The only problem is, it sucks to bleed. But it sucks even harder if you're the one bleeding.

I hope that helps someone.