rushing23

I'm going to put Pagid S Type (AKA dark blues or RS4-2-1) pads on the front of my '02 C2 before my
next DE. My mechanic recommended that I put the
same compound on my rears as well--he said I might
get too much bite up front and cause more lift in
the back end as I brake. I kind of doubt that there is enough of a difference in the Pagid S Type (front) and the ATE Textar (rears) for it to be noticeable. Anyone here just change their front pads when doing DE's?? Any comments on how it affected (or didn't affect) the braking/balance of the car??

mark kibort

That's why he is the mechanic!!

generally, most cars are too biased to the rear anyway. Since most of the braking is from the front anyway, its sometimes a good idea to mix pads. I generally go 4 sets of front for every set of rears.
mk

Bill Gregory

Since 1984, Porsche has used a bias valve in 911's to limit braking to the rear, as they were concerned with premature rear wheel lockup. On the track, I found too much forward bias, so I went to a higher value bias valve from the Turbo, and that helped a bit sending more braking to the rear, which helped to even things out, and add some stability at the track. Others I know with 964's have done the same with the same result. As I recall, 964 Cup cars don't have a bias valve, either.

JC in NY

Where is the bias valve on the 964? I can check on the Cup car if it has one or not.

chris walrod

is this the same (bias valve) for the 993? I find that my fronts wear almost twice as fast as the rears. I also notice that I get front lock-up, while I have never noticed the rears locking, ever.

I wonder, as a percentage, how much does the turbo valve shift the bias?

Bill Gregory

Using Bill Verburg's brake compendium, it shows the following bias valve values:

40 bar 993 C2/C4
45 bar 964 C2 90-91
55 bar 964 C2 92-94, RS, 89-94 C4
60 bar 965 Turbo

Bias valve is about 2 inches long, tube-shaped, about 1 inch wide, sits under the black cover in the drivers side in the front trunk on LH drive. On 964's it's vertical with a rubber cushioned hose clamp around it, with a brake line in and out.

chris walrod

Thanks Bill for the info. Looks as though I have a few choices to play with. I may not want to go as high as the turbo spec, but somewhere in between.

Thanks again!