Spring rate for rear coilovers

[piledriver]

Hate to bump an ancient thread, but there needs to be some clarification from the 935 specs and how those might translate to a beetle or 944T rear suspension.

If the shock/spring motion ratios and weights are all known, you can actually reasonably translate the springs/damping.

I'm currently trying to pull some reasonable numbers out of the available calculators for spring rate and damping.

The trailing arm length on a 911 and its children are IIRC much longer, so a given dia torsion would effectively be softer.
The shock//coil over attaches out BEHIND the axle.
The motion ratios for the rear shocks/coil overs is thus >1.0

The motion ratio of a 944T is supposedly ~.94 up front and .42 out back (pulled from Rennlist etc)
(I suspect similar for the early steel T1/T3 arms)

The front rates ~match up as the strut angle is close.

The rear spring rate and damper rates on a T1 or 944 suspension will have to be >2,5 X the 935 rates to have the same effect at the wheel.

Also, at least for the 934 (assuming same trailing arms), the published rear damping specs are more like 2200/1200.

Note that the base recommended Bilstein damping settings for a baja bug prerunner/race app are almost EXACTLY what is spec'd in the previous post for the 935 (including a 2x motion ratio correction for the rear, again, the weights are about the same, the front ratio corrected damping would be softer on the baja by about 30%)

Note Bilstein makes small body coil over-ready shocks in 6" stroke length, 17" overall (S6G) that take 1 7/8" springs, <100 for the shocks and $40 for the slip on coil over kit. (+ springs) They can be bought in 21 std digressive valvings or custom valved when built for only a little more.
Too long if the car is slammed, but about right if the stock shock length still works.