GTS Suspension Question

[Bootstrap]

I have a 2013 GTS that’s been lowered with eibach springs only (no lowering caps) - bought the car like this. Original wheels, yet I’m struggling with tires rubbing. My options I see are:

- Go back to original springs and maybe add lowering caps - hopefully that lowers the car less than eibachs
- Buy some coil overs and get height adjustability

Question - if I go with the coil overs will I get a warning light in the car when I remove the original shocks seeing they are street/track adjustable from inside the car?

Thanks

[TheMadMachinist]

I too have a 2013 GTS that I addd lowering caps too. I believe it dropped the car about 3/4' of an inch all around. On big bumps my driver side rear rubs at times. After measuring the fender clearance it was clear that the spacing of the tire to fender "side to side" was off I bit. I believe when they hang the body work on these cars this is often the case.

My Gen 4 is the same way.

[Bootstrap]

Thanks - yes, the driver side front is worse for me… ☹️

[TheMadMachinist]

Thanks - yes, the driver side front is worse for me… ☹️

That's interesting I have .430 wide spacers on the front of mine. Never rubbed once.

It kind of makes me wonder what they use for tolerances at the factory.lol

[Bootstrap]

It did have spacers and rubbed ALL the time, now it’s more on full lock on the front.

Really interested to know if putting coil overs if I would get a warning light that the factory shock was missing or just that the street/track buttons would no longer work

[Meteoro]

I have Eibach lowering springs on mine with wider aftermarket wheels, never had a rubbing issue.

[Lawineer]

I bought a 13 GTS with eibach lowering springs too. Without wheel spacers it never rubbed. That's odd. With the spacers it did, a lot. Do you have spacers?

I converted it all to a tractive coilover setup because I am going to full ACR-E level downforce. Otherwise, I thought they were nice on the street. The tractive uses the factory plug so you can have a street and track setting (or whatever you want since it's completely tunable). The remote reservoirs fit perfectly too :)
My driver's side was lower than my passenger side too. Not sure why.

You shouldn't rub. Check for wheel spacers. You'll probably have a hard time finding factory springs for a decent price. Just get a custom set of springs made for you. Got a tiny bit stiffer than GTS and however much shorter you want.

[Bootstrap]

I bought a 13 GTS with eibach lowering springs too. Without wheel spacers it never rubbed. That's odd. With the spacers it did, a lot. Do you have spacers?

I converted it all to a tractive coilover setup because I am going to full ACR-E level downforce. Otherwise, I thought they were nice on the street. The tractive uses the factory plug so you can have a street and track setting (or whatever you want since it's completely tunable). The remote reservoirs fit perfectly too :)
My driver's side was lower than my passenger side too. Not sure why.

You shouldn't rub. Check for wheel spacers. You'll probably have a hard time finding factory springs for a decent price. Just get a custom set of springs made for you. Got a tiny bit stiffer than GTS and however much shorter you want.

Yes, I did have spacers and it rubbed like crazy, almost un-drivable, removed the spacers now it only rubs on the fronts at full lock like turning into my drive. Not sure I want to go full tractive coil overs, also some big $$. Honestly trying to get the easiest way or raising the car 1/2 max without spending huge $$ and not having a warning message about missing controls… maybe it is the custom spring option…

[Whiskey]

I have stock spring with spring Capps and no spacers on my GTS. It never rubs. it's perfect for the street as it doesn't scrape.

[Bootstrap]

So here’s the height plus the rubbing on the front, you can also see when the spacers were in something (I think a wheel well clip) cut the tread to shreds, doesn’t rub in the rear now. Afraid the dealership I bought it from “didn’t want to know” as soon as I got it home ☹️. Love the car and this is the ONLY minor fault I’m trying to resolve.

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[Steve M]

Are those 315s up front?

If so, that may be part of your problem.

[Bootstrap]

Are those 315s up front?

If so, that may be part of your problem.

305 - I’m going to try to go back to stock 295s maybe that few mm will stop it rubbing, but I have heard people run 305 without rubbing. I’d love to put coilovers on and get that adjustability, I’m just worried about getting annoying warning lights on the dash…

[Steve M]

305 - I’m going to try to go back to stock 295s maybe that few mm will stop it rubbing, but I have heard people run 305 without rubbing. I’d love to put coilovers on and get that adjustability, I’m just worried about getting annoying warning lights on the dash…

It's not just the extra width - it is also a substantially taller tire. The combination is likely what is causing your issue.

The R888R in 295/30-18 (OEM Gen 5 front size) is a 25" diameter tire.

The R888R in 305/35-18 is a 26.4" tire.

[Bootstrap]

It's not just the extra width - it is also a substantially taller tire. The combination is likely what is causing your issue.

The R888R in 295/30-18 (OEM Gen 5 front size) is a 25" diameter tire.

The R888R in 305/35-18 is a 26.4" tire.

I saw that, and fingers crossed that fixes the rubbing. Was just looking at all options if it’s still rubs and was a little nervous that I would ruin another set of front tires if it does rub… maybe I’m being too paranoid… thanks for the help, tires it is first.

Still interested to know about the coilover option if I didn’t go with the adaptive coil over would I get an error?

[Steve M]

This thread, while old, seems to indicate you wouldn't have any issues:

https://driveviper.com/forums/threads/2269-MCS-suspension-on-the-GTS

I'm sure there are other threads out there, but I haven't taken the time to do a thorough search.

[Bootstrap]

This thread, while old, seems to indicate you wouldn't have any issues:

https://driveviper.com/forums/threads/2269-MCS-suspension-on-the-GTS

I'm sure there are other threads out there, but I haven't taken the time to do a thorough search.

That’s awesome info - huge thanks.

[Hawk]

Bootstrap
Can you get under the car and measure the frame height to the ground at the rear of the pan under the engine and or what it the height of the bottom of the front fender off the ground (mine is 25 5/8”) ? I have MCS adjustable suspension and have my font ride height set at 4 ¼” and I run the Hoosier R7 315 and only have slight rubbing when the wheel is at a full turn over (turning into a garage or parking space). By looking at the marks on my car it appears that the tire is rubbing the inner fender well lining. Check and make sure one of the fender lining screws have not backed out. Place the car on a flat surface and turn the wheel full over in both directions and check the clearance. The only lights that will flash after changing the coil overs will be for a few seconds at start up In the main gauge it will show “shocks set at race mode” or something like that for a couple seconds. One notable observation. My car has the ride height set the same, the front splitter is the same measurement on both side and if I measure the height of the fenders off the floor they are almost 3/8” different. There is a little variation considering most of the body panels are attached to each other and the chassis with fender clips(or my garage floor is slightly out of whack).

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[Hawk]

In the write up I did on my conversion I detailed the MCS coil over installation (page 4)that may give you some insight
https://driveviper.com/forums/threads/27797-TA-to-ACR-conversion

[Bootstrap]

Bootstrap
Can you get under the car and measure the frame height to the ground at the rear of the pan under the engine and or what it the height of the bottom of the front fender off the ground (mine is 25 5/8”) ? I have MCS adjustable suspension and have my font ride height set at 4 ¼” and I run the Hoosier R7 315 and only have slight rubbing when the wheel is at a full turn over (turning into a garage or parking space). By looking at the marks on my car it appears that the tire is rubbing the inner fender well lining. Check and make sure one of the fender lining screws have not backed out. Place the car on a flat surface and turn the wheel full over in both directions and check the clearance. The only lights that will flash after changing the coil overs will be for a few seconds at start up In the main gauge it will show “shocks set at race mode” or something like that for a couple seconds. One notable observation. My car has the ride height set the same, the front splitter is the same measurement on both side and if I measure the height of the fenders off the floor they are almost 3/8” different. There is a little variation considering most of the body panels are attached to each other and the chassis with fender clips(or my garage floor is slightly out of whack).

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I’m exactly 25 3/4 driver side and 25 5/8 passenger. It’s definitely the inner fender liner that’s rubbing at full lock or in a very tight turn under compression. I’m going to try going back to original size tires that should give 1/4 inch more clearance, that may fix the issue.

Thanks for looking at this for me - very appreciated

[Bootstrap]

In the write up I did on my conversion I detailed the MCS coil over installation (page 4)that may give you some insight
https://driveviper.com/forums/threads/27797-TA-to-ACR-conversion

Wow - awesome write up, all of it…. Many thanks.

[Jack B]

My car is also lowered, my autox tires (fronts) are 315 Hoosiers, no rubbing

[Sniper]

If it's just your fender liner that's rubbing, why don't you try a heat gun and push out the part that's rubbing?
I did this with my Jeep Trailhawk when I went with bigger tires and spacers.

[98intrigue]

To confirm as a couple other articles have mentioned, you will not have a light on your dash for the aftermarket coilovers - your shock setting on the dash will just default to "Race" although it will have no affect on the ride.

Remove the fender clip at 12 o'clock on the rear fenders - that will help with the clip digging into the sidewall on dips.

[Bootstrap]

If it's just your fender liner that's rubbing, why don't you try a heat gun and push out the part that's rubbing?
I did this with my Jeep Trailhawk when I went with bigger tires and spacers.

great idea - thanks

[Bootstrap]

To confirm as a couple other articles have mentioned, you will not have a light on your dash for the aftermarket coilovers - your shock setting on the dash will just default to "Race" although it will have no affect on the ride.

Remove the fender clip at 12 o'clock on the rear fenders - that will help with the clip digging into the sidewall on dips.

I found the clip, and managed to push it as flush to the body as possible, next time I have the wheels off I'll remove it and see if I can grind it down a little.

I'm assuming that everyone is talking about MCS coil overs with the adaptive setting - not the cheaper option of BCS without the remote reservoir?

[Hawk]

I have the MCS 2 way valving, if you’re not tracking the car I would think the BCS should be fine. The problem with the BCS would be finding the appropriate spring rate for the coil over .
Here is the spring chart

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[Bootstrap]

I have the MCS 2 way valving, if you’re not tracking the car I would think the BCS should be fine. The problem with the BCS would be finding the appropriate spring rate for the coil over .
Here is the spring chart

48963

Maybe I missed something, I gather that you plugged the 2 way into the factory electronics so at least the car sees that there is something there (as you say controllable from within the car). If nothing is plugged in as in BCS Coil overs, with nothing plugged in, will the car display an error?

[Steve M]

Maybe I missed something, I gather that you plugged the 2 way into the factory electronics so at least the car sees that there is something there (as you say controllable from within the car). If nothing is plugged in as in BCS Coil overs, with nothing plugged in, will the car display an error?

The MCS shocks do not plug in to anything. All adjustments have to be made manually. Just like BC Racing shocks.

[Bootstrap]

The MCS shocks do not plug in to anything. All adjustments have to be made manually. Just like BC Racing shocks.


aha! That's what I missed. Huge thanks

[No hemi]

My last gen 5 did not have the active suspension but I had lowering caps and 3/8 spacers and it would only rub in the biggest bumps, other than that it was ok, also you need to eliminate the clip as mentioned before, I also had r888r's on SW2's.

[Bootstrap]

My last gen 5 did not have the active suspension but I had lowering caps and 3/8 spacers and it would only rub in the biggest bumps, other than that it was ok, also you need to eliminate the clip as mentioned before, I also had r888r's on SW2's.

perfect - thanks!

[GTS Dean]

After measuring the fender clearance it was clear that the spacing of the tire to fender "side to side" was off I bit. I believe when they hang the body work on these cars this is often the case.

My Gen 4 is the same way.

This is why all true measurements should be frame to ground. Further, you should jounce the car several times, then measure this at the tram gauge holes in the bottom wall even with the axle center lines at both ends. (obviously not many folks can or will do this, but it's the right way) Bodywork is notoriously unreliable.

[TheMadMachinist]

GTS Dean, Point well taken.

Any and all suspension geometry measurements must be taken from the frame . The point I was trying to make is that the body is just kind of bolted on after the fact. Then add the size of the generous tolerances the factory states for the body panels. This can lead to problems with clearance between the fenders and tires. Both in height and laterally.

The very last thing a person would want to do is add a set of adjustable coil overs and try and set the ride hight by measuring the distance between the fender and the ground.

[Hawk]

You defiantly need to measure it at the frame (in the center of the axles) and corner balance it after the initial adjustment. I was just asking fender height as reference as I assumed he did not have the car on a lift. The stock frame height on my TA was 4 9/16” front and 5 11/16” rear, difference of 1 ½” for reference

[SilveRT8]

You defiantly need to measure it at the frame (in the center of the axles) and corner balance it after the initial adjustment. I was just asking fender height as reference as I assumed he did not have the car on a lift. The stock frame height on my TA was 4 9/16” front and 5 11/16” rear, difference of 1 ½” for reference

Thanks for the info.
When adjusting height with different shocks, should we keep the 1 1/2'' difference front to rear or can we vary this ?

[Hawk]

Thanks for the info.
When adjusting height with different shocks, should we keep the 1 1/2'' difference front to rear or can we vary this ?

With the rake angle of the car it would depend what Aero package you have as well as how you are using it (track, spirited street driving or cruising). It looks like you have the 2.0 ,the faster you are going the further it is pushing the ass of the car down and lighting up the front ,it will affecting the cornering at higher speeds. If you like to drive it hard I would keep at least 1” of rake angle, it makes a big difference with the ACR Aero, this is just my opinion perhaps someone with better knowledge about the effect of the rake angle could provide some information.

Don’t forget, if you change the diameter of the front tires it will be changing the rake ,make your adjustments with the tires you intend on using.

[GTS Dean]

I have no experience with aero effects, other than to clearly understand that suspension deflection increases with speed. But, that's why rear spring rates are typically substantially higher with winged cars than non-winged. I try to keep the rake in my chassis around 0.5". 1.5" seems extreme to me under any circumstances, but I would defer to whatever the factory service manual suggests.

[Hawk]

With the ACR Aero the street measurement on the frame is 6” rear and 5” front and the track 5 ½” rear and 4” front (according to Dodge) if you change the spring rate you will need to compensate the rake heights based on an estimate of spring rate and speed. With mine I have stiffer rear springs than stock so I went with only 1 ¼” difference however I did need to play around with the compression and rebound on the coil overs to find the sweet spot.

[GTS Dean]

I guess the diffuser strakes need some extra clearance when it's all working at high speed.