Monday, May 21, 2018
DriveWerks

[Project 328is e36] Full Circle Suspension Fail

Sometimes what seems to be a good deal is in fact too good to be true. For several years I had wanted to upgrade the suspension on the e36 to a true adjustable coilover setup. Rather than send Ground Control two consecutive bills decorated with the face of Grover Cleveland (unlike his terms at 1600 Pennsylvania Avenue), I thought I could get away with buying a used setup and still reap the benefits. Not this time.

I Saw a Shimmering Light

Like most of my shenanigans, it started on Craigslist late one night. I came across a listing that was barely an hour old, so I emailed the seller asking when I could purchase the Ground Control e36 suspension they had for sale. Unlike Milton’s suspension with all the bells-and-whistles we previously installed, the kit I purchased is a conversion kit that doesn’t utilize as many custom parts. It’s made to use off-the-shelf Koni shocks and can be used with stock mounts (as opposed to camber plates). Still present are the adjustable ride height collars, but the ability to lower the ride height is limited by their placement in the stock strut housings. I personally didn’t need to lower the car more than it sat, but those who wish to slam their cars may need shorter springs or to chop the stock spring perches.

My primary reason for wanting an adjustable coilover setup was to increase the spring rate. The 328 has been riding on H&R Sport springs for five years, and they aren’t as stiff as I’d like for my tastes. For a starter suspension they work fine, but the progressive nature of the springs makes turn-in response more sluggish than it needs to be. Unfortunately there aren’t any other drop-in replacement springs with the rates I would need.

Enter the Ground Control kit with Eibach Racing Springs: Using the same style of Koni Sport currently installed on the car, one can switch to the linear rate springs that are both stiffer and quicker to respond. The reason the springs are quicker to respond is because the actual spring rate is instantly exerted once the suspension is loaded, as opposed to a progressive rate spring which has to hit its initial (usually softer) rate before the final spring rate can be achieved. That’s not to say progressive rate springs aren’t as good, but they are designed with a compromise performance in the name of comfort.

Boomerang

For an aggressive street car, the spring rates I went with were 440lb and 550lb for the front and rear respectively. I’m not going to go over installing the suspension as it’s no different than what I performed to Milton’s car. It took me a couple days working in-between rain showers to finally get everything installed. Once the work was completed, the car felt great…for the time being.

The new springs made the car quicker on its feet. Whether is was around town over humps and bumps, or cloverleaf on-ramps, the 270k mile chassis was very poised with its suspension movements. Other contributors to the equation were the M3 style sway bar links and 95’ M3 strut mounts, which made high speed stability feel very reassuring. Contrary to popular belief, the increased spring rate didn’t cause a harsh ride either. Within a couple of hours, I was laughing that Milton had spent over 3x what I paid and I was getting the same thrills. The smug look on my face was going to fade away soon enough.

The next morning, I was headed to work when I encountered some clunks and pops that weren’t what I wanted to hear leaving the driveway. I assumed the suspension had to settle, so I carried on with my day. After a week of attempting to diagnose the unwelcome binding noises by checking torque settings and greasing components, I knew very well I had got what I paid for: a mismatched collection of parts that resembled a suspension. Reluctantly, I decided to remove the Ground Control coils and swap in my old suspension. The battle was fought, and I had lost.

It’s Alright Now, In Fact It’s a Gas

Another weekend passed reinstalling my old parts and I was back to where I started. So what went wrong with all of this? Since this was a used suspension, there were a lot of variables at play, but I’m led to believe I didn’t use the correct diameter front springs which didn’t seat properly and rotated on their perches. There are a few different styles available from Ground Control, and it’s best to get everything as a complete package so you know it fits correctly. Also, the coilover springs are much shorter in length, so anytime the suspension would unload itself, the springs could freely move around. This phenomenon occurs when lowering the car off the jack, or going over uneven pavement, usually followed by a loud popping noise.  To be fair, a set of helper springs to take up the slack would have probably solved this, but that was more money that would be better used towards a properly engineered solution.

There’s always the possibility of user installation error (What do you mean I’m not perfect?), but by this point I was too frustrated and too exhausted to deal with trying to fix the various issues. The cash I “saved” was not worth the time and headaches this project caused me.

Despite the time and frustration, this adventure wasn’t a total loss. I was able to salvage the new strut mounts with better alignment settings. More importantly I learned firsthand what separates a cobbled together suspension from a properly designed one, even if they use similar components. One of these days I’ll bite the bullet and get the real deal, but for now I’ll let Milton revel in the endless comments of how I don’t like to spend money. The best one was a picture of two birds in a nest shrieking, “Cheap-Cheap.” On the bright side, at least I don’t have to remove the H&R sticker from my rear window.

-JC

 

If you’re up for piecing together your own e36 coilover suspension here’s what I tried:

Ground Control Street Conversion Kit

Otherwise this is setup I should have purchased in the first place:

Ground Control Street/Touring Complete Coilover Kit

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