Suspension mods to plant the car at higher speeds

[fcarpio]

The symptom I am trying to fix is the feel of instability at higher speeds. The car does not give me confidence at all. The only suspension mods so far are Eibach SportLine springs. The car felt much better before the springs. At high speeds it feels as it sways a little from side to side. It does not feel stable at all. I have been told that this is just the way the car is, but that is not good enough.

What can I do to make the car feel more stable?

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[NoVaGT]

Suspension "mods" made the car worse........go figure. And thanks for confirming my suspicions.

Well, first I'd return the suspension to stock, then I'd go from there.

Springs, shocks, links, geometry, alignment......it all works together to make the car stable. Evidently lowering it messed something up.

Have you checked the alignment? And how old are your tires?

 

[BmacIL]

1. Alignment - you will probably need camber plates or bolts to get to the proper specs
2. Cradle Lockout Kit
3. Dampers (I am assuming you're on stock ones)

 

[G-Rell]

The symptom I am trying to fix is the feel of instability at higher speeds. The car does not give me confidence at all. The only suspension mods so far are Eibach SportLine springs. The car felt much better before the springs. At high speeds it feels as it sways a little from side to side. It does not feel stable at all. I have been told that this is just the way the car is, but that is not good enough.

What can I do to make the car feel more stable?

Did you align after springs... - camber will "ride" the groves/ruts in the road more than a squarer stance IIRC.

 

[jasonstang]

You need aerodynamic mod.

 

[c-rizzle]

Are you talking about 100+mph speeds? If so then the problem is aero.

You need something like this:

 

[TheReaper]

The symptom I am trying to fix is the feel of instability at higher speeds. The car does not give me confidence at all. The only suspension mods so far are Eibach SportLine springs. The car felt much better before the springs. At high speeds it feels as it sways a little from side to side. It does not feel stable at all. I have been told that this is just the way the car is, but that is not good enough.

What can I do to make the car feel more stable?

What do you consider high speed and what are you doing to make you think the car feels unstable ?

 

[fcarpio]

Suspension "mods" made the car worse........go figure. And thanks for confirming my suspicions.

Well, first I'd return the suspension to stock, then I'd go from there.

Springs, shocks, links, geometry, alignment......it all works together to make the car stable. Evidently lowering it messed something up.

Have you checked the alignment? And how old are your tires?

Alignment is fine, I had the Ford dealership take care of it and it checks out. The rear tires are pretty new and the fronts have maybe 20% life left.

 

[fcarpio]

Did you align after springs... - camber will "ride" the groves/ruts in the road more than a squarer stance IIRC.

I did have the car aligned after the springs but what you are saying seems like what I may be experiencing. I have to pay more attention...

 

[fcarpio]

You need aerodynamic mod.

Huh? Please elaborate.

 

[fcarpio]

Are you talking about 100+mph speeds? If so then the problem is aero.

You need something like this:

You have to be kidding me. Really?

 

[fcarpio]

What do you consider high speed and what are you doing to make you think the car feels unstable ?

100+ is pretty high to me.

Have you ever been in an airboat? It feels very little like that. When you turn the steering a little is not very responsive, like there is a tiny delay. Hard to explain, the car feels more like it is floating rather than on rails like I want it.

I come from a G37s and that car was planted at all times, it gave me a lot of confidence to drive it at high speeds. The Mustang feels like at any moment I could lose control. Kind of like driving a big Pickup truck at high speeds. Not nice at all and the Mustang isn't nearly as heavy as PU. I would like to fix this issue.

 

[sigintel]

context?
Post your alignment specs?
Spring rates?
Stick dampers are setup for stock spring rates.

Tire pressures and temps?
Tire specs, wheels w offsets?
You tracking it?
S550 chassis stock is very stable and you should go run an HPDE weekend.
Death star is fully operational out of the box.

Sidewal transmits force, it needs either preload or higher tire pressure to be tight on center.
Try set pressures at 36/35 cold.
If you get pressures up to 39/38 then drop them back down.

 

[fcarpio]

context?
Post your alignment specs?
Spring rates?
Stick dampers are setup for stock spring rates.

Tire pressures and temps?
Tire specs, wheels w offsets?
You tracking it?
S550 chassis stock is very stable and you should go run an HPDE weekend.
Death star is fully operational out of the box.

Sidewal transmits force, it needs either preload or higher tire pressure to be tight on center.
Try set pressures at 36/35 cold.
If you get pressures up to 39/38 then drop them back down.

Alignment, I lost the paper I got from the dealership but it was all on the green, Fronts were dead on center and rears were either +1.5 or -1.5, I think it was +1.5.

The springs are the Eibach Sportlines, don't know the rates. Stock shocks and struts.

Stick dampers, you lost me. Please be patient, I am learning.

The tires are Nitto nt555 g2 in the rear, pretty new and I am still running the factory PZeroes in the front. Will change those soon. I am using the factory PP wheels. The pressures I think are 32/36 (will change to 35/36) and they do get up to 38/39 when warm.

I am not tracking the car yet.

Definitely not trying to be trollish, I need to see what I can do about this issue.

 

[fcarpio]

OK, I apologize if I came up a little trollish, definitely not intended. I have a sense of humor that I forget some people don't like too much.

Turning humor knob down...

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