OMNI Power Coilover Install Question
 

I'm going to be installing my Omni Power Coilovers this weekend and I have one question with regards to the preloading and initial settings of them.

It says in the instructions to loosen the top nut all the way until it's flush with the end of the shock and have the bottom shock mount adjusted so that the overall shock length is about 2" shorter than the length of the stock shocks. Then install, adjust ride height by turning the shock body, and then finally tighten the top nut once the desired ride height has been achieved.

But where should I set the lower spring perch to? Should it be adjusted so that it is as loose as it goes while still holding the spring firmly in place? If the height adjustment is made through the lower part of the shock body, then why is the spring perch even ajustable? This never really crossed my mind until i had bought them and got them into my hands...

Here's a pic to help illustrate my question. I hope this makes sense. Thanks in advance for any help.

http://img.photobucket.com/albums/v2...mnisEdited.jpg

Well, after a few hours of researching, I figured out the proper way to preload the coilovers.

1. The top nut gets loosened until flush with the end of the shock rod.
2. Push the spring and top hat up until they sit against the nut.
3. Adjust the lower spring perch to hold the spring firmly in place (this is the step in which 'preloading' takes place).
4. Once you have the suspension installed and your ride height figured out you then tighten the top nut to spec. DO NOT DRIVE YOUR CAR WITHOUT THE TOP NUT TIGHTENED.

NOTE: How tight you set the lower spring perch will determine the amount of preload you place on the suspension. If you tighten it a lot, then you get more preload. By leaving it looser (but no less than enough to hold the spring firmly in place) will result in less preload.
Preloading determines the amount of sag (or droop) that the suspension will encounter once the car is sitting on flat ground. The amount of sag in the suspension will have a direct influence on the travel of the shock. I.E. if the shocks have 6" of travel and the sag at a dead stop is 2" then that leaves 4" of travel in the suspension. So if you adjust to have less sag you will have more travel (but you will also have a spring that is compressed more before you evn begin to drive). It's a toss up and a matter of preference.

I will be installing my coilovers with about 1/2" of preload. This means that I will tighten the lower spring perch until firm and then proceed to tighten it another 1/2" up the shock body.

The rest of the height adjustment is made using the bottom of the shock body (the lower bronze part in the picture) as it is independent of preload and shock travel.

Please feel free to add comments as I am new to this and want to make sure the concept of preloading is correctly portrayed.

yeah i'm pretty sure you described it correctly, i didn't preload too much because my coils have an incredibly high spring rate, so i didn't want it any stiffer..

it's sort of like adjusting the dampening, except you're adjusting the spring instead of the shock, but you're right it will result in less travel and a tad stiffer ride because you don't have as far to go...

Yep - at 600lbs front and 331lbs rear you can expect a stiff ride:nods: