On the rear Koni SA again note the extreme non-linearity of the damper to
changes in the rebound adjustment. In this case backing off on the adjustment
from full-stiff to only a 1/4 turn off softens the rebound response to almost
half way between full-stiff and full-soft. Since the dampers have about two
full turns of adjustment then the change from the red curve to the blue curve
represents only about 12% of the total adjustment.
Also, the change in rebound damping due to an adjustment is not even across
the range of damper velocities. Softening the shock initially has a bigger
effect at low shaft velocities. As the adjustment continues to be turned toward
the soft end, the change in rebound damping is more evenly distributed across
the range of shaft velocities.
As with the front Koni SA, note that the compression curves collapse onto
each other indicating that adjusting the shock has no effect on compression
damping. Also observe that the damping forces in compression are very small.
This confirms the rumor that Koni shock offer little (close to zero)
resistance in compression. On the rear this is probably a good thing with an
E30 M3 as it probably helps prevent a loose condition on fast transitions.