advice for suspension setup

c.moser

Member
Apr 29, 2008
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I have a 1990 GT convertible that is basically stock other than exhaust. I want to do some work to the suspension and need some advice on what direction to take. The car will never see a drag strip. My goal for the car is for it to be a nice weekend cruiser that sits nice and handles nice.

So far I have a strut tower brace and a set of H&R springs for the front. My question is what else should I get. I was thinking about possibly getting a set of bullit springs for the rear (I love the raked look) but would it be smarter to go with a set of rear coilovers or try to find a set of H&R springs for the rear? I know I should get subframe connectors, but what kind/brand should I go with? I'm also thinking i should get some control arms. Should I do upper and lower? What brand should I get? I am on a budget so I'm not looking to spend an arm and a leg. Just looking to do some quality upgrades but not spend a fortune if possible. Thanks for any advice
 
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I'm going the same direction as you. Get subframes first, standard length is fine. The car drives and feels so much better:D

Edit: Not sure about standard length for convertables, you may want full length SFC's. Do some research on the forum.
 
I have Kenny Brown subs, I feel they are the best. I would get the rear springs that match the fronts. A nice set of struts and shocks to complement them will do wonders. I have Koni "reds", while they are pricey, they are lifetime warranted. Tightening up the chassis on a vert is paramount. Lower "G" brace in the front helps. If the car is lowered, you're probably going to need a bumpsteer kit. I balked at first, but after adding them, my steering is perfect.
 
I wouldn't mix and match springs. Get rid of the H&R springs you have and buy a matching set of 4. Springs aren't too terribly expensive. Besides, do you even know exactly what rate or type the H&R springs are?

As for a suggestion, I run FRPP progressive rate springs, they used to call them "B" springs, but I'm not sure they go by that anymore. They have a "raked" look, if you're into that. Handling is OK, ride is a little rough, but it's supposed to be softer than the specific rate springs ("C").

That said, reputable companies like Eibach, Steeda, and Maximum Motorsports offer good quality springs.

If you put lowering springs on the car, you HAVE to replace the original shocks/struts. These can get a little expensive. Again, Eibach, Tokico, Koni, Bilstein are all reputable companies. I run Strange adjustable shocks and struts, which are more reasonably priced and I'm happy with the quality so far.

If you lower the car, you also have to consider front end alignment. I'm talking caster/camber plates. I run a set of Hotchkis CC plates, but again- Steeda and Maximum Motorsports sell good stuff.

Subframe connectors? This is where you definitely shouldn't cheap out. This stuff gets permanently attached to your car, so you can't go replacing it all that easily if you end up unhappy with it. I have a set of MM standard length SFCs, and the car is so rigid, I can put a jackstand at 3 corners and leave the 4th hanging, and the car doesn't twist the slightest. Note: WELD in your SFCs, do NOT drill holes and bolt them in.

For control arms, general consensus is that if you're sticking with stock geometry, use pliable rubber bushing upper control arms. Going to solid bushing upper control arms doesn't allow the suspension to go through its natural range of motion without binding and causing unpredictable handling. For the lowers, again, you don't want to go cheap. High-end poly bushings and/or spherical bushings are a good idea. Cheap LCAs have been shown to fail time and time again. Make sure you don't get anything "drag race specific", some of that stuff isn't designed to go around corners. For the uppers, I use Steeda's modified stock Ford UCAs, which have a welded in reinforcement and use better bushing materials. For the lowers, I use Steeda's aluminum 4600 series LCAs, which are supposed to be tough as hell.

I think that pretty much covers it...
 
My recipe for success for what you're looking to do would be the following:

- Weld-in subframe connectors
- 2-point K-member brace
- New struts and shocks all around. Bilstein or Koni preferred.
- A set of coilovers for the front, with 275-lb springs, and you can adjust the height to your hearts content. You can also change spring length/rate way cheaper and easier than with conventional springs if the need arises
- FRPP Cobra front control arms so you have new, upgraded bushings and new balljoints. Huge difference over aging stockers
- Adjustable-height rear lower control arms, which will keep you from tearing your hair out trying to get the correct ride height out of your springs
- Stock replacement SN95 rear upper control arms and new axle-side bushings, which are slightly stiffer than what you have but not too stiff to make things unpredictable.
 
I must say that coil over in the fronts made the biggest impact over the slew of components my mustang has seen over the past 10 years. I must also state that making the chassis more rigid will get rid of alot and I mean ALOT of the play in the suspension and overall feel of the car. So SFC's and even if your not drag racing the car but plan on making a few good hard pulls in its future, install some LCA torque box reinforcements. I've seen cars blow their boxes on stock power like a hot knife through butter.
 
I have a 1990 GT convertible that is basically stock other than exhaust. I want to do some work to the suspension and need some advice on what direction to take. The car will never see a drag strip. My goal for the car is for it to be a nice weekend cruiser that sits nice and handles nice. Just looking to do some quality upgrades but not spend a fortune if possible. Thanks for any advice

Consider just putting some new wheels + low profile tires.

JCPony has a nice collection of 17" and 18" 4 bolt wheels and/or tires that you won't have to worry about fitment on a stock car.

Consider the wheel/tire diameter/width before lowering the car at all.

Low profile tires ride harder than stock combos and will totally change the look of the car.
 
I wouldn't mix and match springs. Get rid of the H&R springs you have and buy a matching set of 4. Springs aren't too terribly expensive. Besides, do you even know exactly what rate or type the H&R springs are?

As for a suggestion, I run FRPP progressive rate springs, they used to call them "B" springs, but I'm not sure they go by that anymore. They have a "raked" look, if you're into that. Handling is OK, ride is a little rough, but it's supposed to be softer than the specific rate springs ("C").

That said, reputable companies like Eibach, Steeda, and Maximum Motorsports offer good quality springs.

If you put lowering springs on the car, you HAVE to replace the original shocks/struts. These can get a little expensive. Again, Eibach, Tokico, Koni, Bilstein are all reputable companies. I run Strange adjustable shocks and struts, which are more reasonably priced and I'm happy with the quality so far.

If you lower the car, you also have to consider front end alignment. I'm talking caster/camber plates. I run a set of Hotchkis CC plates, but again- Steeda and Maximum Motorsports sell good stuff.

Subframe connectors? This is where you definitely shouldn't cheap out. This stuff gets permanently attached to your car, so you can't go replacing it all that easily if you end up unhappy with it. I have a set of MM standard length SFCs, and the car is so rigid, I can put a jackstand at 3 corners and leave the 4th hanging, and the car doesn't twist the slightest. Note: WELD in your SFCs, do NOT drill holes and bolt them in.

For control arms, general consensus is that if you're sticking with stock geometry, use pliable rubber bushing upper control arms. Going to solid bushing upper control arms doesn't allow the suspension to go through its natural range of motion without binding and causing unpredictable handling. For the lowers, again, you don't want to go cheap. High-end poly bushings and/or spherical bushings are a good idea. Cheap LCAs have been shown to fail time and time again. Make sure you don't get anything "drag race specific", some of that stuff isn't designed to go around corners. For the uppers, I use Steeda's modified stock Ford UCAs, which have a welded in reinforcement and use better bushing materials. For the lowers, I use Steeda's aluminum 4600 series LCAs, which are supposed to be tough as hell.

I think that pretty much covers it...

I agree with almost everything but this^^^
Solid bushings will not bind. Just cant work like that, there is 100% more motion with a solid bushing, it will be better in terms of handling over any rubber polly bushing available. The problem with bind happens with having a polly bushing on both sides of the control arm. Thats what doesnt allow the arm to articulate properly, thats why all aftermarket control arms have a spherical bearing on one end and polly on the other (if they dont they are **** and you should stay away from them) The downside to spherical bearings on both ends is you're risking ripping out your torque boxes and thats not fun, so if you plan on running solid bearing control arms inves in some battle boxes or something similar.
 
I agree with almost everything but this^^^
Solid bushings will not bind. Just cant work like that, there is 100% more motion with a solid bushing, it will be better in terms of handling over any rubber polly bushing available. The problem with bind happens with having a polly bushing on both sides of the control arm. Thats what doesnt allow the arm to articulate properly, thats why all aftermarket control arms have a spherical bearing on one end and polly on the other (if they dont they are **** and you should stay away from them) The downside to spherical bearings on both ends is you're risking ripping out your torque boxes and thats not fun, so if you plan on running solid bearing control arms inves in some battle boxes or something similar.

You're right, I should have also said urethane bushings. It's my understanding that the UCAs need to be pliable in all directions, including length-wise (they need to be able to stretch and compress) a certain extent, and anything more rigid than rubber doesn't allow that. The way I see it, if you're serious enough about handling to be interested in running spherical bushings in the UCAs, you should just be looking into a panhard bar/torque arm setup, and eliminate the UCAs entirely.
 
You're right, I should have also said urethane bushings. It's my understanding that the UCAs need to be pliable in all directions, including length-wise (they need to be able to stretch and compress) a certain extent, and anything more rigid than rubber doesn't allow that. The way I see it, if you're serious enough about handling to be interested in running spherical bushings in the UCAs, you should just be looking into a panhard bar/torque arm setup, and eliminate the UCAs entirely.

Compression and extension messes with the instant center/pinion angle. So I would imagine eliminating it all together would only benefit handling and traction as there is limited axle wind up, But being they are spherical they will still allow regular and normal articulation of the suspension in all other movements. Lots of SCCA/NASA classes prohibit things like PHB's and TA's so handling can be done with UCA's its just more difficult.
 
I doubt the op will ever need to get that extreme.

He can stick with rubber uppers, just get a nice set of lowers. My car rides the tits with max motorsports lowers and oem ford rubber uppers. Rear is silent and transitions nicely from lefts to right.

Of course, knowing the ops budget would help too...otherwise we can suggest coil overs and pan hard bars and other expesove stuff
 
I doubt the op will ever need to get that extreme.

He can stick with rubber uppers, just get a nice set of lowers. My car rides the tits with max motorsports lowers and oem ford rubber uppers. Rear is silent and transitions nicely from lefts to right.

Of course, knowing the ops budget would help too...otherwise we can suggest coil overs and pan hard bars and other expesove stuff

I agree, i was "going on the record" :p
 
Thanks for all the info guys. I guess it would make sense just to get a full set of springs instead of mixing and matching. I don't really have an exact number as far as a budget goes. I have around $2,500 burning a hole in my pocket from selling a 96 Cobra I had. I like to to do my mods in segments I guess. For example I want to tackle the suspension first then maybe the exterior next summer, and then maybe the engine after that. As of right now my plan is to get the following:

-full length subframes
-FMS "B" Springs
-Strange Adjustable Shocks and Struts
-Adjustable lower control arms
-CC plates

Anybody have any reviews on KYB shocks and struts? Anything that I'm missing that should be done right away when upgrading the suspension? Thanks for the help guys
 
Thanks for all the info guys. I guess it would make sense just to get a full set of springs instead of mixing and matching. I don't really have an exact number as far as a budget goes. I have around $2,500 burning a hole in my pocket from selling a 96 Cobra I had. I like to to do my mods in segments I guess. For example I want to tackle the suspension first then maybe the exterior next summer, and then maybe the engine after that. As of right now my plan is to get the following:

-full length subframes
-FMS "B" Springs
-Strange Adjustable Shocks and Struts
-Adjustable lower control arms
-CC plates

Anybody have any reviews on KYB shocks and struts? Anything that I'm missing that should be done right away when upgrading the suspension? Thanks for the help guys

Sounds like you're interested in my combo, eh? :D

Summit offers a package with some of those components at a reasonable price, which is partly why I went that direction. They may not be ultra-hardcore race stuff, but I'm pretty happy with the way the car looks and handles. If anything, I might be inclined to change the springs some day, but they are OK for now. The shocks/struts and CC plates have been great so far.

Summit Racing 15-0076 - Summit Racing® Suspension Lowering Kit Pro Packs - Overview - SummitRacing.com

cmb-15-0076_w.jpg
 
Ha yeah I'm interested. I'm not looking for hardcore race stuff anyway, just a nice weekend driver that looks/handles nice. I was looking to see if there were any good packages available anywhere and didn't see that one so thank you for the link