When Dave Hill and his merry band of Corvette engineers designed the C5 suspension, their goal was to deliver slot-car cornering without the bone-jarring ride that usually accompanies tighter hardware. There's no question that they did a superb job with the base models, and the Z51 suspension option was even better. The arrival of the Z06 in '01 set new standards of cornering and handling for the Corvette, and did it without any significant compromise in ride comfort. Yeah, it's a little stiff, but if you want something softer, you drive a Lexus, right?
Since our goal with the C5 on a Shoestring project has been to upgrade the '97's all-around performance, we felt it was time to improve the car's suspension in preparation for our upcoming engine modifications. All that power is useless if you can't translate it into carving up canyon roads or ripping through corners under full control.
Keep in mind that depending on how extensive a suspension upgrade is, there may be changes that cause an increase in tire wear and interior noise. Ride quality may also suffer. With that said, there's still no better adrenaline rush than cutting the apex of a corner harder and powering out faster.
We went to the folks at Vette Brakes and Products (VBP) in St. Petersburg, Florida, and laid out our suspension-upgrade goals. VBP has been around for more than 30 years and has mastered the science of Corvette handling, both on the street and at the track. For our application, the company suggested its Extreme Touring System.
This system includes VBP's own composite monosprings, which are engineered to perform on the street or in competition use. Bilstein Sport Shocks and VBP front and rear tie-rod ends are included in the package, along with adjustable stabilizer-bar end links, eight-inch specialty spring bolts, and graphite-impregnated polyurethane bushings.
Since the VBP Extreme Touring System did not include stabilizer bars, we decided to see how the original bars performed in concert with the suspension upgrade. The base '97 Corvette suspension utilizes a 24mm front bar and a 19.1mm rear bar. Adjusting the end links resulted in an improvement, but we didn't feel we were getting the most out the new suspension. We needed bigger bars.
The '97 Z51 suspension used 30mm bars in the front and 21.7mm units in the rear. While that's a hefty increase, the '03 Z06 used an even bigger, 23.6mm rear bar. For our tastes, that's even better. VBP sells a 32mm front bar and a 24mm rear bar. We decided to add both to the previously installed Extreme Touring System. These bars require polyurethane bushings and increase ride harshness and vibrations, so they probably aren't the best choice for most Corvette owners.
Suspension work usually requires the use of a lift and power tools, but it is possible to do the job with the car supported on heavy-duty, six-ton jackstands. (Remember: Never crawl under a car that's not supported by high-quality jackstands!) You'll still need air tools, regardless of whether you're doing the work standing up or on your back.
If you've never done suspension work before, you may be better off enlisting the services of an experienced shop. In our case, we asked John Wilson of Auto XTC in Clearwater, Florida, to handle the installation.
Once our new underpinnings were in place, we took the Shoestring C5 to an alignment shop to set up the new hardware. This is a critical step in any suspension upgrade, since the new suspension's altered geometry will drastically affect the handling of the car. Give yourself a chance to become acclimated to the car's revised handling feel before taking a nice, slow drive to the alignment shop. If you have access to a trailer, that's even better.
We took the Shoestring C5 to 1 Stop Car & Truck Repair in Venice, Florida, for its alignment. 1 Stop's techs had no problem getting the car realigned using their state-of-the-art Hunter alignment and balancing equipment. They did an excellent job of setting up the suspension, and soon we were on our way.
It didn't take more than a few miles and a handful of corners for us to feel the difference VBP's Extreme Touring System had made in our C5's handling dynamics. The car felt glued to the pavement, without any sacrifice in ride quality. And with the adjustable stabilizer-bar end links, we'll be able to fine-tune response to our liking.
Next month we'll take the first step in extracting more horsepower from the stock LS1 with an SLP headers-to-tips exhaust system. That should put our new suspension to work!
Although the Corvette's alignment range allows a chassis setup appropriate for racing, we chose to go with the stock alignment specs. If you're willing to accept the compromises in tire wear and driveability an aggressive alignment brings, we suggest resetting camber to -1.0 degrees at all four wheels as a (conservative) starting point. For racing, set the camber adjusters for the maximum negative camber, with no more than a 0.25-0.50 degree difference front to rear.