180 lbs Progressive Springs... Heads Up or Down, Sorry, Stupid Question Time Again Options

[dbledsoe]

I'm installing Bilstein shocks (rear) on my 914 Buick V6 conversion. I bought 180 lbs progressive springs from PP (which were actually shipped from GPR). My question is, does it make a difference how the progressively wound coils of the spring are positioned i.e., close spaced coils should be at the top, or should they be at the bottom?

I apologize for what is probably a very basic question, but doing a search turned up nothing (that I could find to address the question) and I don't have any experience with progressively wound springs.

More photos tomorrow on my slowly advancing Buick V6 into P914 project (this is/was my first 914 [I have two of them now] and my first engine conversion... other than putting a Volvo B1800 engine in a Sunbeam Alpine 28 years ago... and yes I still have it but that was a lot simpler... or maybe I was less hesitant).


Thanks for your help!

Don

[Thorshammer]

I hate to differ, and I am unsure of how you came to this conclusion. But the real answer is, You always run the close wound side of the spring to the sprung mass. or to the car side. because the spring has more weight in the tighter wound section it will add to unsprung weight if it is run with the tightly wound coils towards the trailing arm. There is no compressive difference with the spring either way. Andy may have encountered some very odd natural frequecy which made his react differently with the spring mounted different, but in my experience with suspension, there is no difference. The spring will still reach a steady rate once the softer coils are compressed, this does not change with mounting.

As you compress the spring the closely wound spring sections will compress more quickly, but at a point, they will slow in their compression (or cease if they are coil bound) and the load will be carried by the coils that are spaced further apart. No load changes will occur if the spring is turned around. If Andy did get a significant change, I would look at upper and lower spring seats being different and the spring not resting properly on the spring seats, or a very odd frequency induced issue, but I can not speculate on how that may happen . Maybe I am missing something , but I don't think so.

Erik Madsen