Ground Control Suspension Upgrade

I've been looking at upgrading the Z3 suspension for some time now. Any time I ran into someone who'd upgraded their suspension, I'd pick their brain about what they liked and what they didn't like. During my last trip to Laguna Seca, I talked with Lester regarding his M-Roadster. He opted to go with a Ground Control set up, and he's been very happy with it. He said it offered a lot more adjustability than other packages he'd considered

When I got back home, I looked up Ground Control (GC) and studied their offerings. Once I'd decided on what I wanted (singly-adjustable front and rear), I called them up and arranged to visit their facility (just a few miles from home). They were very helpful, showing me the parts they manufacture, and all what comprises one of their packages. They asked me what sort of driving I'm interested in, and based on that they selected the appropriate spring rates for the front and rear.

Typically, when upgrading the front struts, you'll reuse the stock housing. I was interested in being able to revert back to stock though. Luckily, GC manufactures strut housings, so no parts are permanently modified. Additionally, they could provide a anti-roll bar link mount that would allow me to use a bar designed for an M-Roadster or M-Coupe if I so desired. An extra bonus with their package... the ride height is adjustable. Again, there are so many options with this package.

I eventually placed my order for a package with their strut housing and doubley- adjustable front/rear. They were out of the rear shocks that I'd need, but they offered to fill the order with singly-adjustables in the rear and then I could upgrade later if I was still interested.

So, today I drove up to the GC shop and picked up the package. Initial impressions: very, very nice! The rear shock mounts, coil seats and ride-height adjustment fixtures are beautifully machined. The aluminum parts are tastefully anodized, and the strut housings are painted to match the Koni shocks. They provide an allen wrench for ride-height adjustment and a knob for adjusting the shocks. The strut and strut cartridge were pre-assembled, and some assemblies bundled together to help avoid confusion during installation. Finally, they preset the adjustments on all four corners based on our discussions.

The works! (fronts/rears)

Rear shocks (Konis) with GC rear mounts

The rear coil assemblies

Close-up of the spring seat and ride-height adjustment. It's not visible in the picture, but the adjustment collar has a locking bolt.

Front strut assemblies

Close-up of front strut ride-height adjustment. Here you can see the lock bolt on the adjustment ring.

End view close-ups of the front struts (note adjustment controls).
  • Front spring-rate: 250
  • Rear spring-rate: 425

Installation Details: Front, Rear

Questions or Comments
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