Bias valve

[powaw]

I just installed a set of cup IIs (7" front/ 9" rear) on the 87 na. The car is used for autox. They came with 205 front and 255 rear tires installed. I'm going to use up the rest of the tires before putting more rubber under the front and maybe taking some out of the back. I immediately noticed that it locks the fronts up now under hard braking. Car has new ss flex lines, rotors, pads, and fluid. I need to be able to move some braking force to the rear. What options are out there besides changing to different pad compounds end to end? Looking for an adjustable bias valve. Thanks for the help.

[nynor]

you can adjust the rear ride height so that it is equal to the front. this is supposed to make a great deal of difference in the braking. and it is easy to do.

[flash968]

the offset of the particular set of your 993 Cup wheels (as there are a few different ones out there) could also affect how it brakes

agreed that ride height affects braking - a lot more than you think too

not sure if they cross over to the 944, but they do for the 968 - we generally swap from the 5/18 to the 5/33 - it comes with some touchy braking in the wet, but works well in the dry - some part numbers for factory bias valves numbers are:

5/18bar 951 355 305 01
5/33bar 928 355 305 01
5/45bar 964 355 305 00
5/55bar 930 355 305 01
5/60bar 965 355 305 01

[powaw]

thanks. I didn't mention the car has full delrin, koni coil overs, 250# springs, 27mm t bars, 968 m030 sways, lowered and leveled. The suspension is there and working great, the addition of all the rubber out back has really changed the braking. I will soon be moving to the third set of tires for the season (to get more rubber in the front) and want the flexability of adjustable bias.

[nynor]

ah, more info.