[s-cars] RE: Confessions

[Keith Maddock]

James,

It seems to me that you have too much rear brake bias.  What did you do to your rear brake bias valve when you upgraded your brakes?

When you lock the center diff, then the driveline is coupling the wheel speeds front and rear, therefore it acts to perfectly keep the amnout of wheel slip between front and rear the same.
This can easily mask the fact that your brake bias is too much to the rear.

However open up that rear center, and the over-biased rear brakes are simply  slipping the rear wheels more than the front, which means the rear tires have less lateral traction, and this gives the rear end the tendency to step out.

Time to install a adjustable bias valve perhaps, or play a bit more with the one you have.

Cheers,
Keith

Keith Maddock, TRW Automotive,  Koblenz, Germany
Slip Control Systems, Systems Design, Traction Control
+49 (0)261/ 895 2474    -   -   keith.maddock at trw.com


>>> James Bufkin <jbufkin at austin.rr.com> 16:35:01 23.10.2003 >>>
How would a car say with a locked or open center differential, 298mm vented
drilled rotors, race pads and 4 pot AP racing calipers on all 4 corners
handle a situation like this?

I have done some hard braking a few times and the back end does two things,
with the center unlocked there is a very noticable tendency for the back
end to step out.   Braking is good and strong with the center locked and
the rear step out tendency is reduced.

My car has no ABS as you know.

James