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      07-02-2011, 08:09 PM   #1
SlamMan
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DIY: Ground Control Coilover Conversion Kit Install

Disclaimer: I make no guarantees that this guide is accurate and that you won't break your car or hurt yourself doing it. Proceed and follow this guide at your own risk.

This kit isn't actually on the www.ground-control-store.com website. To get it you need to call Ground Control at 530-667-8600 and ask for Jay. If you tell Jay how you'll be using the car he'll be able to put together a custom kit to suit your needs. He set me up with some relatively soft springs and I haven't noticed the car to be much stiffer than stock.

I've never actually done any suspension work before this but I'm a glutton for punishment so I figured I'd give it a shot and take a lot of pictures as I went. I called Ground Control whenever I had questions and they were more than happy to provide answers. Now that I've done this job once I think I could do it again in about 6 hours. I think with this DIY and the right tools, most handy people could do it in about the same time. Maybe less if your experienced and have a friend helping. Maybe more if you get in a jam.

The guys at Ground Control have looked at this DIY write up and were happy with it. I might go so far as to say it's got an unofficial seal of approval.

If you have any experience with this or similar suspension work and have something to add, please do so. I'm more than open to updating this DIY. Particularly if I've used any incorrect or inconsistent terms that you can correct me on.

I got most of the basic info on how to do this from rldzhao's DIY: Aftermarket Spring Install thread.

Here's where I got the torque specs: rldzhao's Torque Spec Thread

To do this you'll need a pair of spring compressors and a 21mm and 22mm strut nut socket pictured below. I picked up a www.Metalnerd.com strut nut socket from www.europarts.com per another members suggestion but you can find various strut nut sockets on eBay too.

You'll also need sockets AND wrenches up to 22mm, a few SAE sockets and wrenches as some of the hardware on the kit is not SAE, and a torque wrench. Obviously you'll need a jack and jack stands. Two jacks are nice but not necessary. Air tools are also nice to have but not necessary.



Important! Before you do anything be sure to measure your ride height of all four corners and write it down.

We'll start with the front. After you jack the car up and remove the wheel, start by marking the vertical position of the sway bar link bracket/spring seat. Mark all the way around this bracket so you'll be able to line it back up if you go back to stock. Ask me how I know this is important...

Then you can undo the sway bar link at the lower point and the brake line bracket/steering knuckle bolt. If your working on the drivers side you need to disconnect the headlight level sensor so you don't damage it with the suspension hanging on it.





If you have ESC, and chances are you do if you purchased this kit, next you'll need to remove the plastic cover on top of the shock perch and reach under that cover with your fingers and pop the connector off the top of the shock rod. Just get a finger on each side of the connector and pull it straight up.





After this you can jack up the suspension to compress the spring and put the spring compressors on. This is much easier than trying to just tightening them down to compress the springs.

Then you can remove the top shock rod nut. To remove it, you'll need either the shock rod nut socket and 10mm socket, an open end wrench and a 10mm socket, or an impact wrench.

As an alternative, you can also unbolt the 3 nuts of the perch before taking off the shock rod nut and lower the entire assembly with the perch attached. I did one side each way and didn't find much advantage one way or another. If you do it the second way just be sure to be aware that there may be some tension on the spring when you remove the shock rod nut.

Either way, carefully lower the strut assembly. It helps to lower and let everything rest on the jack so it's not hanging on the brake line.

Remove the stock perch if you didn't leave it assembled. Then you can install the slotted Ground Control perch.




Next you'll need to pull the strut assembly out, mark the position of the sway bar link and take off all the unnecessary bits. I don't know if there's a trick to pulling the damper out of, what I think is called the steering knuckle, because I had to knock it out with a hammer.

You can see in the next few pics that I've used a sharpie to also mark on the damper body where the center of the sway bar link joint is located so when you remove the stock bracket you can put the GC bracket on and the joint will be in nearly the same position. To remove the stock bracket you'll have to hammer it off. Just be sure to mark the joint and bracket position first! Then you can put on the GC link bracket and line the joint up with where you marked the stock joint and the bracket at or just a hair below the vertical line you made a while back.





Now you can reassemble the everything according to the provided diagram. According to GC, the threaded red sleeve will rest on the damper body where it tapers out.






Now you can put the entire assembly back in the steering knuckle, run the shock rod up through the perch and attach the top shock rod nut. To tighten it down, this is where you really need that the shock rod nut socket and a 10mm deep socket to tighten down the shock rod nut without spinning the shock rod.

According to Ground Control, the correct way to adjust and attach the sway bar links is with the vehicle on its wheels and the suspension under the compression from the weight of the car. So you just put the wheels back on and take the car off the jacks so it's setting and compressing the suspension in a ready to drive state. Make sure the wheels are set straight forward too. Then you just have to squeeze under the car and twist the links to set the length so the bottom end of the link slides easily into the sway bar. The idea is that the links/sway bar don't have any load as the car is sitting static. Once you get the nuts tightened up just jack the car back up, take the wheels off and tighten all the link nuts up to spec.

Here's what it looks like all buttoned up and a pic of all the parts that came off the front and didn't get reused.




That's pretty much it for the front. Now on to the back...

Jack up the back, pull off the wheels and remove the trunk liner. The trunk liner comes out of the E90 fairly easily once you pull out the middle section and all the black plugs. Then you just need to remove the 2 bolts on the lower suspension arm and the top shock rod nut. On the lower arm, remove the smaller damper bolt first then the larger bolt. Don't for get to unbolt the headlight level sensor when your working on the drivers side too!





To remove the spring and damper you have to push down on the lower suspension arm. Everything came out fairly easily.



Important update! Aleks of www.alekshop.com was sharp enough to notice a stock part that should have been removed. The black cup circled in the next picture should be removed. It can be knocked out with a hammer. This should let the threaded cylinder to sit up into the frame a little more. I will take pics and add them to the DIY as soon as possible.



Once everything is out just take all the unused bits off the damper and the upper bushings from the frame. Then reassemble per the GC diagram. The bushings included with the kit sandwich on top (in the trunk) and on bottom (in the wheel well) of the upper mount.

Important! When you reassemble the two bolts in the lower suspension arm be sure to get the outside bolt for the wheel carrier and arm lined up and assembled first before tightening the damper bolt. If you tighten the damper bolt first you may not be able to get the wheel carrier back in the arm as it will be too tight.

Be careful when you're lining up the wheel carrier and arm not to let wheel carrier fall behind and below where it connects to the arm. It's tough to explain but it happened to me and I spent at least an hour trying to get it unstuck and back out front so I could get it aligned and reassembled. As per the spring swap DIY, you can jack up the lower arm and use a wrench as a lever to line up the carrier and arm holes.





Here are the pieces that were replaced on the rear.



Once you get everything back together just make sure everything is torqued to spec and you're done. If you found this useful you can buy me a beer next time you come through Denver.
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Last edited by SlamMan; 03-06-2012 at 04:24 PM.
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      07-02-2011, 08:26 PM   #2
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What kind of beer do you like? This was awesome, I'm thinking of doing this to mine, but scared that the ride will be a little bumpy and harsh.
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      07-02-2011, 08:37 PM   #3
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I like all kinds of beer as long as it's cold! Ha!

I asked my girlfriend what she thought of the ride quality and she said it wasn't much different now. I honestly didn't ask what spring rates Jay gave me but my invoice has part numbers 0700.250.0325 and 0800.250.0600 for the springs. Maybe someone can tell me what the spring specs are from those numbers.
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      07-08-2011, 12:40 AM   #4
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Quote:
Originally Posted by SlamMan View Post
I like all kinds of beer as long as it's cold! Ha!

I asked my girlfriend what she thought of the ride quality and she said it wasn't much different now. I honestly didn't ask what spring rates Jay gave me but my invoice has part numbers 0700.250.0325 and 0800.250.0600 for the springs. Maybe someone can tell me what the spring specs are from those numbers.
you got soft spring rates...its 325 for front and 600 for rear...those numbers at the end signify the spring rates....btw, great DIY...wish the guy I paid to do mine would have had it!....
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      07-09-2011, 09:53 PM   #5
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great write up... The rear where the perch sits into the car, that top black piece should be removed. You can take a mallet and hammer that off.
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      07-10-2011, 01:40 AM   #6
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I'm not 100 % sure what part your referencing. The bushing where the top of the shock meets the frame? Unfortunately I didn't get any pictures of them on the car.
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      09-26-2012, 03:25 PM   #7
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I just want to add two points for the install or for troubleshoooting after install:

1. Ensure that the Sway bar brackets that attach to the damper are tight enough. It should be tightened to ensure that the sway bar link has no excess clearance when fully assembled. If there is clearance, the link will move laterally along the bolt and cause a "clunking or knocking" noise over any bump even as small as an expansion joint. It will sound like something is loose in the front end. This could be mis-diagnosed for a worn link(s) as the sway bar link assembly will seem like it has play coming from the link area when the vehicle is off the hoist and in ground position (provided the sway bar has not been adjusted for preload).

2. Watch the rear headlight self leveling assembly arm orientation on removal and ensure that the orientation is duplicated on install. If it is installed incorrectly your headlights will aim high. There are lots of posts on this elsewhere on the forum.

If the kit is installed correctly, it does not produce any noise and you should not be blinding anyone with your headlights while driving. It seems like there are a number of areas that are suseptable to poor install and consequently poor performance in the vehicle.

If the kit is installed correctly, it peforms well.
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      10-10-2012, 09:05 AM   #8
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Where did you source your suspension boots from? Why didn't you reuse the rear over sleeve for the shock?

Great thread BTW!
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      10-10-2012, 09:17 AM   #9
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The bump stops with the boots came with the kit.
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      01-01-2013, 01:24 PM   #10
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Excellent write up. I bookmarked it for future use
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      01-01-2013, 02:44 PM   #11
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Thanks for the detailed install.
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      05-08-2013, 09:46 PM   #12
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I attempted this install at a shop, but stopped when the mechanic advised me that the rears had a good chance of flying off if my ride caught air. Said they were not long enough even maxed out. Did you have any drivability issues once installed?
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      05-08-2013, 11:57 PM   #13
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I had no issues and the setup saw a couple track days. Might want to call GC and ask them for input on what your shop said.
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      05-09-2013, 09:13 PM   #14
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Quote:
Originally Posted by Tomz_M3 View Post
I attempted this install at a shop, but stopped when the mechanic advised me that the rears had a good chance of flying off if my ride caught air. Said they were not long enough even maxed out. Did you have any drivability issues once installed?
Do you have the height adjusters for the rear?
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      05-09-2013, 10:29 PM   #15
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Do you have the height adjusters for the rear?
Yeah. Even at the tallest setting, there was still some play in there, the tech thought it might have a chance to fly off in a turn. I saw it myself, and when I called Ground Control, the mechanic was assured it wasnt an issue.

Bottom line was that he refused to install it, citing safety issues.
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      05-10-2013, 05:08 PM   #16
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And the shock and lower spring bucket was all hooked up? Pics please!
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      05-20-2013, 08:59 PM   #17
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I have another shop taking another crack at it tomorrow. Will post pics.
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      05-21-2013, 08:28 PM   #18
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Went to the shop and it turns out the previous owner didnt include the bump stops. Can I use E36 bump stops on this application??
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      12-11-2013, 01:24 AM   #19
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how has the suspension been treating you? I'm thinking about pulling the trigger on these my car has Edc does it function the same?
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      12-11-2013, 05:26 PM   #20
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I've had this kit since 2010 and like it a lot, even though I no longer track my E90. I've been thinking about getting the next level softer of springs though since the roads here tend to be craptacular. The thing that tipped me into this setup was the camber adjustment - I was plowing through tires at the track.

Yes, EDC still functions without any issues.

What other questions do you have? Not sure if he's still there, but Jay at Ground Control was an AWESOME resource for me and the shop I had install it (who had no idea what they were doing and I'll never go back to).
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      06-21-2014, 11:21 PM   #21
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i bought a used set on here, but it didn't come with the rear shock dust overs. Would the stock ones be fine?
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      06-27-2014, 10:56 PM   #22
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Hi guys -

Not sure if you would be able to pitch in your opinion but I have already searched online as much as I can and I am really down to my last resource which is this thread I came across.

I purchased the same exact kit for my M3 E92. After the installation was done, the alignment was next and everything was ran to spec. Here are some details:


Left Front:

Camber: -1.7
Caster: 7.5
Toe: .42

Right Front:

Camber: -1.7
Caster: 7.3
Toe: -.24


Left Rear:

Camber: -1.6
Toe: .06

Right Rear:

Camber: -1.7
Toe: -.09

Thrust Angle: -.01

I get in the car and the steering wheel pulls a sharp right just rolling at 5 mph. The alignment is spot on, however I am not sure where to even start to look for issues. Anyone ever had this problem???

thanks in advance,
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