Hyperco 5.5" single pigtail rear spring test

[Loren]

Simple math here. One rear corner = 2300 x .5 x 40% or about 460 pounds.

Your 123# spring is compressing approximately 460/123 or 3.75" to an installed length of about 8.25". (this is disregarding motion ratio just for simplicity)

Your 275# spring is only compressing 460/275 or about 1.75" to an installed length of 10.25"... a full 2" taller than stock.

Your actual results were about 3/4" more than that, but looking at the side-by-side photo, the old springs were maybe half an inch shorter than the new ones. That's part of it. The rest probably comes down to not considering the motion ratio, etc.

My point is that if you'd done a little math, you should have EXPECTED your new 275# spring to raise the car by at least 2" without question. Can you get 10" springs or 9" springs?

Very cool that "standard" race springs fit so well. How 'bout some photos of how they fit in the perches? This is neat stuff!