Does the SC have a Brake proportioning valve

[jabb]

I have SC front brakes on my 914. I am going to upgrade the rears to SC brakes also. When I added the SC brakes to the front I removed the PV form the 914. Now I am putting SC brakes on the rear and I am not sure if the SC has a proportioning valve.

If it does can I just put the 914 valve back or do I need to get the SC valve...

[masraum]

No, a valve was added to the 3.2L cars because the caliper piston sizes were changed, but before that there wasn't a valve.

[MotoSook]

This is from Bill Verburg's brake page:

For the front, the 282.5x24 mm rotors and calipers used on '84-'89 Carrera 3.2 models(as described above), for the rear 290x24 mm rotors and wide M(~53cm2/caliper pad area) calipers from the same cars. These calipers used 2x48mm front pistons and 2x42mm rear pistons. The front calipers are widened versions of the earlier SC A calipers. The width was obtained by inserting ~4mm spacers between the caliper halves. The rear calipers are the widest versions of the previous series M caliper, also widened via ~6mm spacers inserted between the caliper halves. These wide M calipers also have larger pistons, 2x42mm(rather than SC 2x38) and are used with 290x24mm rear rotors. The decrease in the front to rear hydraulic bias ratio necessitates a 33 bar proportioning valve with a .46 reduction factor be used on the rear circuit(this is the stock '84-89 Carrera p/v). Both front and rear pad areas are the same as used on the SCs. The benefit of this combination is the marginal increase in thermal reserves for track use. Auto-Crossers also often like this setup with the bias valve removed, this enables the rear of the car to turn better under braking, it however will also cause the rears to prematurely lock under extreme conditions, this is generally not desirable.

[jabb]

Thanks... Quick reply