If you have a keen eye, you may have noticed that some of the suspension components shown in the photos covering our brake upgrade looked much like some 70-plus-year-old actors and actresses-much too good considering their age and mileage accumulation. That's because work on a vehicle often progresses at a different pace than the editorial covering that work. It obviously makes little sense to remove the brakes, install replacements, and then remove them again to work on the suspension. So while he was doing the brake upgrade, Trey Hanson (of SpeedHound Performance) also cleaned up some suspension components and replaced others. It's obvious from the Project C4orce photos that the entire car is currently a work in progress. Furthermore, these photos were shot over an extended time period, so the state of cleanliness, or the lack thereof, may be inconsistent.
After any vehicle has been driven 100,000-plus miles, the condition of various suspension components is suspect at best. Obviously, mileage takes its toll, but sometimes that isn't entirely apparent. All components don't wear at the same rate, and band-aids applied by a previous owner can often mask or disguise a failure that's just waiting to happen. Unless the previous owner kept records and passed them along with the vehicle, the most sensible approach is to simply replace all the normal "wear items" in the suspension. On the other hand, if you have documentation that some of the components were replaced in the not-too-distant past, it doesn't make a lot of sense to replace them again.
For Project C4orce, we started our suspension shopping list with tie-rod ends, and added upper and lower ball joints, control arm and sway bar bushings, shock absorbers, and plenty of degreaser. Although we'd do much of the cleaning after removing individual components, wrench turning is much more pleasurable when you don't have to continually wipe a grease/brake dust/road grime stew from your hands. Hanson chose to avoid use of harsh "industrial strength" engine degreasers, which often remove more than grease, and leave a residual odor that hangs around longer than grandma's perfume. Instead, he used more environmentally friendly cleaners and (water) hose pressure to remove the bulk of the grease stew. Then, he bead blasted or solvent washed the individual components.
After completing the clean-up work, Hanson, who is now known as Mr. Clean, replaced the ball joints, tie-rod ends, and control arm bushings with new parts from Vette Brakes and Products (VB&P). We elected to upgrade to polyurethane bushings rather than stock rubber replacements. Although they're slightly more expensive, they offer superior performance and durability.
Like VB&P, most Corvette parts suppliers offer suspension kits as well as individual components. If you're planning to do a complete suspension rebuild, compare the prices of kits and the individual components included. Sometimes complete kits offer an attractive cost savings.
To complement the suspension rebuild, we added a set of QA1 double adjustable shock absorbers and VB&P adjustable upper control-arm shafts. These parts will not figure in our $15,000 total build budget because they're considerably more expensive than a number of perfectly acceptable alternatives. That doesn't mean we've scrapped the original premise for Project C4orce, only that we have other plans for the car after the original project is completed. Another consideration is that in addition to generating a cost blueprint for a high-tech C4, our plan is to use the project to develop and highlight a variety of unique products. So even if you have no plans to alter your C4's powertrain, Project C4orce will still have some items of interest.
The QA1 shocks are of particular interest to anyone with a race-oriented or true dual-purpose C4. The capability of adjusting both compression and rebound allows the shocks to be optimized for virtually any type of driving environment and road condition. And since adjustments are made by rotating easily accessible external knobs, shock settings can be quickly altered to suit widely different driving conditions. Switching from optimum race to optimum street settings can literally be accomplished in a matter of minutes.