Foxbody Irs Alignment

[FoxMustangLvr]

Before you cut anything you might want to install and check. I was given stock rear coils that still had the ford labels on them and my car is lowered. There must be a height variation in the upper spring mounting point between my old fox chassis and the cobra chassis. My fox is a 1985 station wagon... so there’s that. But you might want to check first.

I wonder if the back of your car is just a little heavier than my Mustang 5.0?

 

[nelzfoxes]

I wonder if the back of your car is just a little heavier than my Mustang 5.0?

I honestly don’t think the difference is all that much. But... maybe.

 

[90sickfox]

My IRS has the stock spring height...

 

[nelzfoxes]

My IRS has the stock spring height...

Wow! There must be a difference with between early fox chassis and later! Truthfully it bothered me at first that my car was low at the rear. Up front are ford b or c springs. I can’t recall which. When I had the 302 in there occasionally it looked nose high. Now it has a 351. The stance looks perfect and has grown on me. The car handles well. IRS foxes are awesome!

 

[FoxMustangLvr]

My IRS has the stock spring height...

I cut this much spring....

for this much ride height....

I have 245/40/18's in the back which I believe is a 25.7" tire

 

[90sickfox]

Looks good FoxMustangLvr

 

[bird_dog0347]

I drove mine with cut factory springs in the rear and Proline's up front... I didn't like it at all. The ride was way too stiff up front and way to bouncy in the back, plus it wasn't level. I cut a full coil and was lower in the rear. Now with coil overs all around it's very well balanced and level.

Before:

After:

 

[FoxMustangLvr]

I drove mine with cut factory springs in the rear and Proline's up front... I didn't like it at all. The ride was way too stiff up front and way to bouncy in the back, plus it wasn't level. I cut a full coil and was lower in the rear. Now with coil overs all around it's very well balanced and level.

Before:

Sounds like you cut too much off of the rear springs and the bouncy indicates bad or incorrect rear shocks. Aside from that, I bet your new setup is pretty dang sweet. If where I lived had better roads I'd go for a stiffer (more sporty) setup. The winter here kills the roads and all the patch work makes for a bumpy ride so that dictated my suspension design first and foremost. I still have suspension tuning to do on car my like adjusting my rear end links to eliminate rear steer and adjusting my sway bar end links correctly. Hopefully I'll get that done this summer.

 

[bird_dog0347]

Sounds like you cut too much off of the rear springs and the bouncy indicates bad or incorrect rear shocks. Aside from that, I bet your new setup is pretty dang sweet. If where I lived had better roads I'd go for a stiffer (more sporty) setup. The winter here kills the roads and all the patch work makes for a bumpy ride so that dictated my suspension design first and foremost. I still have suspension tuning to do on car my like adjusting my rear end links to eliminate rear steer and adjusting my sway bar end links correctly. Hopefully I'll get that done this summer.

That was with factory 04 Cobra bilstiens in good condition, the problem was the spring rates (thus the wheel rate) were grossly mismatched front to back with good dampers at all 4 corners.

 

[LarsD]

This is making my want an IRS for my hatch again.