I tow alot with my Lumina, and recently the rear struts have bitten the dust. The rear leaf spring is starting to devolop some sag from towing also (currently about 1-1.5"). I'm going to build a coilover kit to use as helper springs in the rear of my car.
I'm planning on keeping the monoleaf, and adapting the struts to coilovers. I'm looking into getting a low springrate (I'm thinking 110, 130 or 150) since these will be used as "helper springs" to eliminate sag and sway when towing a trailer. (I'm also thinking about pulling a swaybar off a Euro to help stiffen up the rear a bit more also.) Most guys seem to run 250lb springs when doing a full monoleaf delete, but since I'm keeping the [saggy] monoleaf I'm thinking I should go with softer coilovers.
These are the parts I'm looking at:
Just looking for some input on what rate springs would be best for my application. I don't want to go too soft and defeat the whole purpose of doing this, or go to hard and have to swap to something softer.