Foxbody springs question on rears

[lt1 kenobi]

So I took a suggestion off of here to lower the rear with fox body mustang springs... I cut a coil off to get the ride height I want.. I took the exact same amount off .. they measure the same but when I put them in the pass side sits 1/4" lower.... Now I placed the pigtails on the rear both facing out of the drivers side.... is that correct??? I could cut more off the pass side spring but they are cut the same right now... I don't get it?

 

[Anonymous]

First, I know nothing about using Fox Body springs in a G-Body. Don't even know what the spring rates are.

But, 1/4" isn't much. So, I'd ask if one side might have the rubber insulator still in and the other doesn't, or maybe the rubber is in both sides and one is wore thinner than the other.

Or, do you have a battery mounted on that side of your trunk or some other something on that side?

If none of those, I'm sure you have bounced the *ss-end up and down, and that didn't help. How about if you unhook the shocks? Does that cure it? Maybe it is in the shocks?

If it were me, I'd check the above, and before I'd cut any further, I'd drive it a bit and see what settles/happens.

 

[lt1 kenobi]

Thanks for the advice I'll try that first.... I'm thinking it could be in the shocks as well...

Thanks

 

[BMR Sales]

they measure the same but when I put them in the pass side sits 1/4" lower....

Did you take measurements with something in the drivers seat to make up for driver weight? If not that might be your 1/4"

 

[James Bond]

was that difference present before the spring swap? maybe a body mount issue? i'd measure to a some frame pts.

 

[Norm Peterson]

Shocks won't affect the ride height unless you replace non-gas pressure shocks with gas pressure shocks (raises it a little) or vice versa (drops a tad).

Order of magnitude, Fox Mustang rear springs should be somewhere between 50% and 100% stiffer than G-body rear springs. In the Fox chassis, the springs sit on the rear LCA about 70% of the way from the chassis pivot to the axle pivot. That's a motion ratio of 0.7, so the effect on wheel rate (what you're ultimately looking for) is 0.7 (squared) or 0.5. So you double the spring rate in order to cover for the way it is being installed. The Fox is a little lighter than a G, hence the springs are likely a little less than double the G springs' rate. Until I can get at my paper Moog catalog, figure 200-ish lb/in.

It doesn't take much to create only a quarter of an inch in ride height, and it's even possible that preloaded sta-bars could cause this to happen. But other things can cause this as well. Springs that aren't quite the same rate to begin with, or not exactly the same free length.

Try swapping them left to right and see what happens.


Norm

 

[kyhunter89]

Try swapping them left to right and see what happens.


Norm

smart and simple man Mr. Norm

 

[soultron]

Is this even a viable idea for a g body? I've never heard of such a thing.

 

[Norm Peterson]

Is this even a viable idea for a g body? I've never heard of such a thing.

Fox-body springs? The springs don't particularly care what car they're on, as long as the ends will work with the spring seat style(s) and the spring has the desired rate and loaded height. I'd at least run the numbers. No, I haven't and don't know of anybody who has done this.


Norm

 

[soultron]

Is this even a viable idea for a g body? I've never heard of such a thing.

Fox-body springs? The springs don't particularly care what car they're on, as long as the ends will work with the spring seat style(s) and the spring has the desired rate and loaded height. I'd at least run the numbers. No, I haven't and don't know of anybody who has done this.


Norm

And here I figured the spring was a bit more intelligent. dancin_banana.gif