Low 964

So the fronts I have on my 90 C2 will be 36/40????? NOT CHECKED and the rears I have bought to fit are, 28/30, I assume this is a good combo, should I change the bias valve, will I have braking issues?

Bill Verburg

No that's standard 964. Some guys that track a lot like that setup w/o the p/v.

While I don't particularly care for p/v(actually they are line pressure limiters) they do get the back to take some of the load off the fronts, w/ some cars(like 964) this is mostly helpful

ghhally

Paid 90£ for piston and dust seals for 2 calipers ( 8 sets ) delivered to my doorstep.

Low 964

Bill just to clarify..
I am fitting 28/30 C4 4 pots to replace my 90 C2 2 pot rears, as you say that is a standerd fit, do I need to change the bias valve...what is p/v....not sure on some of your abreaviating!!!!


ghhally...I got quoted £60 for just seals, dust and piston, and £40 for delivery from that place

Computamedic

Pete,

If you click here you'll get a summary of Bill's detailed brake specs which show the standard C4 has a 55 bar proportioning valve (Bill's p/v abbreviation) whereas the C2 with the 2 pot rears has a 45 bar valve. Logic says you should change it - I know others who have made the change did.

Steve Brookes' "How-To" here may prove helpful.

Regards

Dave

Low 964

Thanks Dave, guess Bill is still asleep!

DK

There is some great info here, which was accurate for my porsche calipers:
http://www.zeckhausen.com/How_to_Measure_Pistons.htm