I had a set of IMP Z-Pro Series lowering springs installed today along with CC plates and Koni struts. The front of the car sits fine, about 1.5" lower. The rear however is about 2.5" taller. My question is what the heck could have happened? I have attached some before and after pics.

 

just give it time, take about 2 weeks for springs to settle, just be patient

 

Wow springs need time to settle but i never saw anything like that. thats really high.

 

You put the rears in the front and the fronts in the rear?

 

holy crap. Springs should NEVER be like that. But I'd wait for r3dn3ck or blake to chime in. They know their stuff

 

I could see setteling in about 1/2" or so but lifting it 2.5" when it should be dropping it 1.6" means it would have to settle about 4".

I did check to see if the shop did swap them but the springs with the smaller coil are on the rear and the open end of that coil is pointing to the drivers side of the car.

CHRIS

 

Springs take less than a day of driving to settle back in. Mine was on jackstands for two months and they settled in after driving for several minutes.
Lifting it is a problem.......i don't think it's possible to accidently mix the fronts with the backs. you should take them back out and check them out, it's not hard.


yes i replied.

 

lol looks like you have hydraulics... yeah dude, something is not right somewhere lol

 

Wow!!!

There is something not right there for sure.They did'nt put some Rancho shocks on there did they?? LOL

 

4 X 4

 

It should only take about 24 hours for them to settle, but that is way too high. On the rear you have to index the spring, seat the bottom correct or it will ride high, it says this in the install instructions that come with all the ones I've put in. The bottom end of the spring should face forward and be in the middle of the pearch. If you had install done at a shop take it back and have them check...also check the part # on the spring box and springs them selves...I had a set of FRPP mispacked once (3 Bs and one C). I say that's way too "jacked up".

 

Me The Next Day....

 

I took one of the springs out to compare it to the old ones. I also took some pics of how they are installed. The springs did not come with instructions, just wrapped in paper in the box. I did measure from the wheel center to the top of the wheel opening and got 17" in the rear 15" in the front. I am not sure what the factory spacing is though so if someone knows or is still sitting stock and can measure it would be appreciated.

CHRIS

 

No rubber on the bottom seat? Should have one. This makes no dif with the hight tho. They look ok, shorter that is. May just need to wait. I note your end face outward, I was instructed to make them face front?

 

Just took another pic of the car in about the same position as an older pic I have so that you can see the difference (before springs has the bra on the front). As you can see the front looks like it came down but the back looks taller.

CHRIS

 

Well I loosened the shocks and spun the springs around so that they faced forward to see what it would do, nothing, didnt move it a bit.

CHRIS

 

Try sitting on or pushing down the back bumper. Does it spring up and down or is it stiff like it is binding up somewhere??

 

Do you still have the factory pinion snubber on there? that will make it set high, I just installed some h&r super sports on my 96gt and it set high in the back till I removed the factory pinion snubber, put the h&r pinion snubber in there and everything set perfect

 

I checked the "bounce" and it was normal, not stiff. I will check the bump stop.

CHRIS

 

You're not the only one having this problem. I was literally the first one to get a set of these springs and I've had them on for over a month now and the back end is still way up in the air, my neighbor even asked me yesterday what the hell I did to my car. It's the exact same on my car, the front came down nicely but the back end looks awful and now I have a fairly loud creaking noise coming from the back end. I can't figure out exactly where the noise is coming from but having it jacked up like that is seriously messing with something. I figured I would give it 2-3 weeks and it would be fine and it's going on 5 weeks or so now and I'm really not happy with it......

 

You guys need to contact the company and raise hell, include pictures of your cars also. That's 2 people who have the same problem.

 

The rear springs should NOT cause the car to sit that high even during the settling period. There's a problem. Give me a few to try and figure it out.

Do you have a part number for the springs or any spring-rate info on them? How tall are they when they're not installed?

If nothing else, I've got a set of Mach1 rear springs for cheap. They sit about .75" lower than stockers and will sit perfect if you cut 1/2 coil.

 

ok... I think I've got it nailed.

The new rears look like they're a HELLUVA lot higher spring rate (based on coil size and design) than stock or even most lowering springs that I've seen.

Step 1: remove the springs
step 2: determine the spring rate of the rears. If it's above 200 lb/in it's almost certainly too high.
step 3: if the springs are too stiff you must not use them. You'll be loose as a goose in corners and spinning out could be a real concern. Trim 1/2 coil from your stockers to lower ~1", or trim 1 full coil from the top of the new springs and check ride height. If it's too high trim 1 more coil. DO NOT cut coils from the bottom of the orange springs.

Looks like the rear springs are the wrong height and rate to me though. Rear spring rates don't change much from stock to lowered unless there's a torque arm in the mix.

 

r3dn3ck, The springs are from Mustangtuning.com http://www.mustangtuning.com/imp-z-p...s-springs.html To your concern about the rear being loose, it feels very loose compared to stock. The specs from mustang tuning are:

Specifications:

* Compatibility: Fits all 1996-2004 Mustangs Except 1999+ Cobra
* Spring Rate:
o Front: 700-760 lb/in
o Rear: 275-300 lb/in
* Approximate Amount Lowered (V8):
o 1996-2004 Coupe:
+ Front: 1.75”
+ Rear: 1.6”
o 1996-2004 Convertible:
+ Front: 1.9”
+ Rear: 1.5”
* Finish: Orange Powder Coated

 

haha those are horrible!

 

This is why you never by off-brand springs. CALL MT AND ASK FOR A ****ING REFUND.

 

That's a really really high initial rate. I would look for a better set of rears with a more progressive rate like 170-310. You can cut a coil off what you have and it'll be better. It's gunna ride kinda harsh but that's what you've got. You're really loose right now partly because of the springs but also because your car is at a noticable rake and the weight is leaning forward. Getting it back down where it belongs will help reign that back in.

You can also cut half a coil off your stock springs and see how you like it. If it's not low enough cut off another 1/4 but no more than that. Trust me. The pinion snubber is kind of a shock.

Your fronts are pretty bloody aggressive too. I'd expect you to have a heavier than normal motor. It's gunna be a lively ride.

 

I just double checked the pics and in my opinion, even cutting 1 full coil from your new rears will not drop it enough. I wouldn't cut more than 1 coil though since they're at the pitch they are. The initial rate is what's holding the car up in the air. Cut your stockers or buy my machs or send back the new ones and get a spring with a lower initial rate.

In any case it looks like you read the ad and wanted just a max effort part without having done the homework. When it says max, it means max. Max is rarely any use on the street. Most people are well satisfied with sport level suspension. Choosing the right parts is really a science when it comes to things like spring rates and attachment points and materials.

You have stock LCA's and probably stock UCA's so you've got a really aggressive spring on a so-so suspension system. If you're going to keep the springs, hopefully you have beefier shocks and struts already and you should think about stronger control arms and maybe a panhard bar.

DISCLAIMER: I am not a mechanic. I'm an enthusiast and I've been there and done that on suspension so take ^ for what you will. You should really consider a more streetable set and sell those for what you can. Try FRPP B or C springs. C is pretty stout but street friendly. B is lots less bumpy but not up to C level performance potential.

 

r3dn3ck, I am waiting on a call from MT today. After reading the forums over at corner-carvers.com I was under the impression that these springs would give me streetable performance. I do have Koni yellow single adjustable struts up front, looking to get matching shocks in the near future. Speaking of shocks, what is your opinion on the quad shocks? I have had a bunch of people try to tell me that they do nothing for the car. I know they help with wheel hop at launch when I go to the strip. Thanks for all the help, I will post after I get my call back.

CHRIS