Hanson and his bushing machine...
Hanson and his bushing machine also attacked the rear suspension. As in the front, we used polyurethane bushings for improved performance.
Since the front control arms needed nothing more than ball joints, bushings, and cleaning to be perfectly serviceable, the adjustable upper control-arm shafts from VB&P are another "extravagance." They're designed to allow a wider range of caster adjustment, so that desired camber settings can be implemented without having to compromise caster settings.
Although the frames of most C4s don't distort enough to make desired caster and camber settings difficult or impossible to achieve, there is the occasional car that is a problem child. An extreme change in ride height, a damaged frame, a suspension component alteration, or some combination thereof can create alignment issues. Establishing the settings recommended for daily transportation is rarely a major challenge, but the aggressive caster and camber settings typically used for autocross and race track adventures are a different matter. With adjustable shafts, future experiments with caster/camber settings will be easy to perform.
The third part of our suspension upgrade is a new wheel-and-tire combination. We selected Sport Edition V6 wheels and Dunlop Sport 9000 tires from the Tire Rack. The Sport Edition V6 wheels are obviously a "tribute" to original equipment C6 wheels, and that fits in nicely with our high-tech update theme. As for the tires, we've had nothing but excellent experiences with Dunlops in the past, so we selected 275/40ZR17s mounted on 17x9.5-inch wheels for the front and 285/35ZR18's mounted on 18x10.5-inch wheels for the rear.
Now all we have to do is get the powertrain finished so we can go for a test ride. That won't happen for a few months, but in the meantime, we have plenty of other things to keep us off the streets and out of trouble. Stay tuned.
| Difficulty Index - 5 Wrenches |
| Anyone's Project: no tools required | 1 Wrench |
| Beginner: basic tools | 2 Wrenches |
| Experienced: special tools | 3 Wrenches |
| Accomplished: special tools and outside help | 4 Wrenches |
| Professionals Only: send this work out | 5 Wrenches |
 Depending on how deeply you...  Depending on how deeply you want to get into "reconstructive surgery," you may want to consider removal of the bat-wing assembly. In addition to facilitating cleaning, having the bat-wing out of the car simplifies clean-up and repair of any brackets that have deteriorated or been damaged. It also makes replacement of the bushing mounts a lot easier. |  The rear spring was in excellent...  The rear spring was in excellent physical condition and performed properly when the car was last driven, so we simply bolted it back in place after the bat-wing was reinstalled. |  One issue we found with the...  One issue we found with the QA1 rear shocks is the top eyelet and bushings aren't the proper width to fit a C4. |
 A pair of fender washers on...  A pair of fender washers on each side is the easiest fix. We're currently looking into having spacers of the proper width manufactured to our specs. |  The suspension is now ready...  The suspension is now ready for wheels. We didn't have enough time to derust the hub, but that will be taken care of shortly. Even with the car up in the air, you can tell the polyurethane bushings removed a lot of play from the suspension. |  Nothing sets off a clean frame...  Nothing sets off a clean frame and new brake calipers and rotors like a Dunlop Sport 9000 tire mounted on a Sport Edition V6 wheel. Unfortunately, we can't show you a better view because the hood and many of the panels have been removed pending installation of the engine. |
 These adjustable upper control-arm...  These adjustable upper control-arm shafts from VB&P are preproduction models. We're testing them on Project C4orce prior to their general release. | | |