Looking to finally get my 91 firebird lowered.
Want to get some opinions on lowering springs options that will work with the swapped engine.
It has an aluminum LS1 and 4L60E. Also has tubular k-member up front and 4th gen rear out back. v6 springs all the way around currently.

What lowering springs would work with my setup and what modifications if any (like cutting a coil) would be needs?

Thanks in advance.

 

Im currently on eibach pro springs. Bought them when my car was also still a 2.8. I like the way they sit, wish the back was a bit lower though. Heater hose isolator mod was done on the back springs. My car had an iron block 5.3 though, not sure how much that will affect height over an aluminum ls1.

 

I'm in the same boat, I was thinking new lowering springs or ground control jack kit.

 

V6 springs worked well for me with LS1/T56 w/AC.

I cut half a coil from V8 springs for LS1/4L60E w/o AC.

Both ended up pretty much stock ride height.

If your goal is lowering, you'll need to do something else.

 

How about weight jacks.You can adjust the height to suit you.

 

Curious. Has anyone ever cut a whole coil? I got the same prob. But I got old V8 Eibac's. still sits high. Car's not on the road yet, but still.

 

I'm going to try the Moog 5660 springs for the front. I have an '84 Trans Am, and the 5660 springs are for the 1991 and 1992 Z28, standard transmission, without A/C. I suspect that's the 1LE springs.


Moog 5660 installation height: 10.75"...load: 1538 lbs...spring rate in lbs per inch: 598


That's 150 lbs lighter than my stock springs. Maybe I'll get the height I'm looking for.

 

The Moog 5598 springs are for the V6. Installation height 11"...load: 1520 lbs...spring rate in lbs per inch: 347

 

Thanks for the replies so far. As it sits right now with v6 springs it is pretty even. But definitely want to go lower.

I had forgot that you had mentioned that to me. I will have to look into it.

 

They came in handy when I made my swap to LS.

 

I have a LS1/4l60e in my car and installed Eibach Sportlines during the LS Swap. I like the height that it sits at, it's lower than stock so it looks good but not so low that I have issues scraping during normal driving.

The ultimate solution is weight jacks or air ride for adjustability. For me and how I use the car, it wouldn't be worth it. Plus I got lucky and found some new in the box Eibach springs on craigslist for $50.

 

Used the weight jacks on my setup and am supremely happy with them.

 

Ground control jack system.... they suggested a spring rate for my ls1/stiffness I wanted. If unhappy they will sell just a different spring rate in the future.

 

I put in Eibach Pro-Kit in mine

LS1/T56
UMI Tubular Kmember/AArms

The ride height is a little tall for my liking

https://i.imgur.com/aA2IfVh.jpg

 

My 91 RS has LS1/T56 swap, chrome moly k member w/arms, AC delete, fiber glass hood etc.

The before the swap ride height was perfect with Eibach Sport lines with the 1.6 inch drop in front & 1.3 inch in rear.

Afterwards the RS looked like an airplane taking off with the front an inch or so higher than the rear. Cutting half a coil was close but we cut another half make it a full coil removed from the front springs. The look was perfect but this resulted in about a 2 inch drop in front. Scraping on bad roads happens. Down south the better roads it's good but up north on the rougher roads there are lots of issues.

3/4 of a coil would probably have been about right. Heater hose might and more weight reduction might salvage the springs but I think it will take new springs with a slight cut.