I'm looking to buy some hypercoil/eibach linear springs for the rear. I want a 1-1.5" drop. The spring rate will be either 450 or 500#'s. I'm just not sure how tall the springs should be to give me that drop.

 

What rear arms or adjusters are you using or are you running a true coilover?

 

I have kw v3 shocks, spl rear camber arms, stock 06 springs on cut(.5") spring mounts.

 

Bump for answers

 

Measure the distance the spring needs to fit, you don't have an adjustable shock body so your stuck with what length you need. You nay need to run SPL spring buckets and helper springs to get the proper drop.

 

measure the height of you current springs deloaded and subtract your desired drop distance. The new spring rates will also be a factor since they are stiffer than what you currently have and therefore will not compress as much under the same load. The math below is just an idea of what kind of difference you could see. I don't know what percentage of the curb weight is unsprung, so I'm just going to say it is all sprung for this example:

The curb weight of a 2006 is ~3,400 lbs with a 53/47% (front/rear) weight distribution. 3,400 lbs * 47% = ~1,598 lbs on rear end. Divide by two to estimate load on each spring = ~800 lbs vertical load on each spring.

'06 OEM rear spring rate = 427 lb/in so, so a 800 lb vertical load would compress the spring ~1.87"

If you bought a 500 lb/in spring, under the same 800 lb load it would only compress ~1.6"

Again, this is just a theoretical example and is not meant to give you a precise answer. However, you will need to consider this. You have adjustable height shocks so you don't need to be super precise because you can make adjustments with them also.