Hi All,
Been back through all this and came to the conclusion that as I'm E36 based I'll follow mperman's suggestion and go for these as a first attempt
http://www.merlinmotorsport.co.uk/p5...duct_info.html
They are close to the
REAR
MR = 0.63
WR = 90lbs (220lb spring, freelength 8")
Freq = 1.24 cps (softer than front)
he quoted being 225lb, 2.25" ID 6" length
Only difference is that the free length is 6" not 8". Does this affect the calculation. I can't see the free length figuring in any of the equations directly but I may have missunderstood.
I've gone for 6" as that's the maximum travel my dampers allow so any extra length is just more hard work compressing them in the first place.
When the half shafts are almost horizontal (just sloping diff to hub slightly) the length with the top adjuster at a low point (40mm of lowering left on the thread) is 5".
I suppose another way of looking at it is if I go for the 8" at the lowest ride setting then there is no chance of them popping off where as with the 6", if I adjust to the lowest they could just about slip out of position, not that I plan spending much time shooting through the air dukes of hazzard style.
In this case the best option is
http://www.merlinmotorsport.co.uk/p5...duct_info.html