Spring change or Aero

[Lawineer]

Did the OP check his alignment?
Fwiw I have acr spring rate and not much aero (side skirts, chin spoiler, ta spoiler) and it’s fine. Keep in mind, the gts is a good bit more sprung mass than the acr iirc so that probably helps a little, too.

[13COBRA]

I wonder if the OP can see the model number on the springs on his car. They are on Eibach's and H&R's etc. If my car had 1480's it would be undrivable for me. The stock 1300's are ridiculous, I'm running 1200 now to not bottom out, but my car would be much faster with 900-1000 and some kind of setup to not bottom out.

Why not run 900s and a spring stop?

[TKO MOTORSPORTS TEAM]

Since it was brought up, does the TKO bump steer kit help? I've never heard anyone talk about this kit but I can't be the only one that is annoyed by the bump steer in these cars. I hate the fact my wheels sit nearly 2" inside the the wheel well but I know putting wheel spacers on will only make the bump steer worse.

Our bump steer correction kit does help. Some customers who install see 1-3 second lap time improvements; We love our customers but we think 1-3 seconds maybe a bit generous and is probably really just driver confidence is improved and it feels like 1-3 seconds.
Wheel spacers wont really change bump steer to much and the general rule is dont use wheel spacers unless you absolutely have to. Spacers will change scrub radius and of course front track. Widening the front track is not a bad thing in most cases to a certain point. Changing your scrub radius because your using wheel spacers can cause problems like slow turn in , increased tire wear, and a heavy feel in the steering

[Arizona Vipers]

Why not run 900s and a spring stop?

Hey dude! Can you send me a link to exactly what you are talking about?

[13COBRA]

Hey dude! Can you send me a link to exactly what you are talking about?

Tons of options. It's not meant to act as suspension, basically just a bump stop to keep it from bottoming out.

https://grandprixauto.com/bump-stop-spring-2000lb

https://pitstopusa.com/i-23901183-la...ref=brand:4818

[TKO MOTORSPORTS TEAM]

Tons of options. It's not meant to act as suspension, basically just a bump stop to keep it from bottoming out.

https://grandprixauto.com/bump-stop-spring-2000lb

https://pitstopusa.com/i-23901183-la...ref=brand:4818

Just a heads up. Bump stop springs are really hard to work with and have alot of down sides to them in road race applications. You will also need to machine some parts so they dont destroy the shock body , cap and shaft. Only place we have ever used bump springs is offroad applications.

[13COBRA]

Just a heads up. Bump stop springs are really hard to work with and have alot of down sides to them in road race applications. You will also need to machine some parts so they dont destroy the shock body , cap and shaft. Only place we have ever used bump springs is offroad applications.

Correct, machine caps for above the shock and below the mount. Ideally, I'd like to try about 20 different sets of shocks in order to fine tune it to nearly bottoming out, but not haha I just don't have the time nor patience for that.

[TKO MOTORSPORTS TEAM]

Correct, machine caps for above the shock and below the mount. Ideally, I'd like to try about 20 different sets of shocks in order to fine tune it to nearly bottoming out, but not haha I just don't have the time nor patience for that.

Bump rubbers and packers is what all of us use. Super easy to work with, quick changes, limitless combos and cheap

[13COBRA]

Bump rubbers and packers is what all of us use. Super easy to work with, quick changes, limitless combos and cheap

I like the idea of bump rubbers, except they just become a wear item. I'm not 100% sold on spring stops either...still in the process of weighing my options.

Should be finally getting the measurements on my frame today, and will hopefully be ordering that pan.

[TKO MOTORSPORTS TEAM]

I like the idea of bump rubbers, except they just become a wear item. I'm not 100% sold on spring stops either...still in the process of weighing my options.

Should be finally getting the measurements on my frame today, and will hopefully be ordering that pan.

Since your a TKO customer you have access to all our support. Which includes race engineers, product engineers, install help, set up info , track data, etc. If you have questions, need trouble shooting or you just want to discuss an idea you can email or call we are always glad to help.

[13COBRA]

Since your a TKO customer you have access to all our support. Which includes race engineers, product engineers, install help, set up info , track data, etc. If you have questions, need trouble shooting or you just want to discuss an idea you can email or call we are always glad to help.

You guys are top notch.

[White Snake]

I wonder if the OP can see the model number on the springs on his car. They are on Eibach's and H&R's etc. If my car had 1480's it would be undrivable for me. The stock 1300's are ridiculous, I'm running 1200 now to not bottom out, but my car would be much faster with 900-1000 and some kind of setup to not bottom out.

Sorry for the long departure, my world had caught on fire since my last post...I will try to answer previous questions as best I can.
Shock assembly KW part # 95181595A. I am not sure if these are Gen 4 ACR-X or not and I am not really sure how to read the spring rates on the springs themselves.
The shock assemblies have upper and lower adjustable knobs (I assumed for rebound and dampening), initially we set them all to 0 or the lowest setting assuming that this would result in the softest setting...it appears that this assumption is vastly incorrect. So after playing around with some of these adjustments that has been some improvement in drive characteristics. I am still a bit hesitant to really push these tests.
No alignment check as of yet but it is on the agenda...like I said, it has been nuts over here lately!

[Lawineer]

I'd definitely start with an alignment.

[chiromikey]

Obviously you should perform an alignment any time you change suspension parts but I’m not sure why so many are suggesting this as a fix to what seems to be an obvious shock problem. Did you have the shocks tested before installing? Shocks are a wear item and buying used can be sketchy, especially if they were on a car that was run hard. I wouldn’t be surprised if these have an internal failure or aren’t valved properly for your spring rates.

Good luck and please keep us updated.

[Lawineer]

Obviously you should perform an alignment any time you change suspension parts but I’m not sure why so many are suggesting this as a fix to what seems to be an obvious shock problem. Did you have the shocks tested before installing? Shocks are a wear item and buying used can be sketchy, especially if they were on a car that was run hard. I wouldn’t be surprised if these have an internal failure or aren’t valved properly for your spring rates.

Good luck and please keep us updated.

What makes you say it's an obvious shock problem?

[chiromikey]

What makes you say it's an obvious shock problem?

His initial post with the description of symptoms. He talked about unpredictable and sudden weight transfers and the feeling of getting launched up a ramp over high speed bumps. This sounds more in line with uncontrolled damping. I’d expect alignment to be described as unpredictable in a lateral sense instead of weight transfers or getting launched upward.

I know others have far more suspension knowledge than I do and I’m hoping he figures this out and lets us know. My opinion is only based on my own experiences and the limited amount of information that we have from an internet post so right or wrong, I’m willing to learn something here.

[TKO MOTORSPORTS TEAM]

His initial post with the description of symptoms. He talked about unpredictable and sudden weight transfers and the feeling of getting launched up a ramp over high speed bumps. This sounds more in line with uncontrolled damping. I’d expect alignment to be described as unpredictable in a lateral sense instead of weight transfers or getting launched upward.

I know others have far more suspension knowledge than I do and I’m hoping he figures this out and lets us know. My opinion is only based on my own experiences and the limited amount of information that we have from an internet post so right or wrong, I’m willing to learn something here.

Un-controlled/incorrect dampening or damaged shock is definitely a possibility so your on the right track but just a little ahead. Dyno shocks prior to install is also a great idea.

[GTS Dean]

If you have shocks properly sprung and valved for aero loading control, then put them on a car with no aero, I'd opine that you're about guaranteed to be oversprung and overdamped. My guess is that the springs are too stiff to start with and the valving - particularly rebound - is too harsh. If you are unloading on the backside of a bump and the tires are going light because the shafts are not moving fast enough to follow the road, you will have daylight underneath the tires and zero control. It could also be bad bump steer at full droop. Not good Goose.

[Lawineer]

His initial post with the description of symptoms. He talked about unpredictable and sudden weight transfers and the feeling of getting launched up a ramp over high speed bumps. This sounds more in line with uncontrolled damping. I’d expect alignment to be described as unpredictable in a lateral sense instead of weight transfers or getting launched upward.

I know others have far more suspension knowledge than I do and I’m hoping he figures this out and lets us know. My opinion is only based on my own experiences and the limited amount of information that we have from an internet post so right or wrong, I’m willing to learn something here.

Under load, the suspension moves and if it's not aligned properly, it will likely move into a direction you don't want it to move into. My car was perfect example. When I frist got it it, under heavy braking, it JERKED HARD to the right, despite driving dead straight on a flat road. Now, that COULD have been suspension in one corner being busted, but it could also be alignment.

[TKO MOTORSPORTS TEAM]

Under load, the suspension moves and if it's not aligned properly, it will likely move into a direction you don't want it to move into. My car was perfect example. When I frist got it it, under heavy braking, it JERKED HARD to the right, despite driving dead straight on a flat road. Now, that COULD have been suspension in one corner being busted, but it could also be alignment.

Broken or warn out suspension for sure you nailed it. Most likely warn out front aft control arm bushing. This is great example of correcting the basic mechanical foundation of the car before going after the more complex problems like shock valving, spring rates, aero , etc