Like the first generation C5-R, the new chassis is built around production C5 Corvette framerails and suspension cradles that come straight off the Bowling Green assembly line. Unlike the first design, however, the new one utilizes fabricated control arms rather than stock production arms. The custom arms are similar to the stock units except they are 1.5-inches longer, giving the new car a 3-inch wider track. The broadened stance improves handling by decreasing roll and lowering the center of gravity. It also increases the tires' contact area and decreases the loads the tires must sustain, both of which lead to better handling and longer tire life.
A final advantage of the widened track is increased aerodynamic downforce. The widened body, necessitated by the wider track, benefits from a wider splitter and diffuser. The splitter and diffuser are parts of the underside of the body that direct the flow of air between the car and the track surface to increase downforce. In addition to improving the C5-R's handling, the second generation chassis also offers the benefit of reduced weight. The two new race cars tip the scales at about 110-pounds less than the initial pair.
As with engine size, weight is carefully governed by the series rules. Each class has a minimum weight that cars must meet, and formulas that try to even the performance potential of cars that weigh in differently. A smaller engine air restrictor hampers lighter cars while heavier cars benefit from a larger one.
So, why build a lighter car if that will only lead to a smaller restrictor and less engine power, or that will require the addition of weight to meet the minimum number dictated by the rules? The first reason is that all weight is not created equal. By building a car that's too light to begin with, engineers can specify exactly where the required extra weight is to be placed. They actually ballast the cars by adding bars of a heavy metal alloy to very specific areas. By directing where the weight goes they can improve handling by optimizing balance and lowering the center of gravity.
Also, reduced weight, at the cost of some engine power, is desirable at certain tracks but not so at others. For the '99 season, and until the Mosport race this last August, the team could not take advantage of this because they could not get the first generation C5-Rs below 1,200 kg. In contrast, the new chassis can be pared down to the next weight break, 1,150 kg. On tight tracks like Laguna Seca and Mosport, which place a premium on handling over raw power, the C5-Rs will turn better lap times at 1,150 kg, even with less power. At high-speed tracks like Daytona and Road Atlanta, the higher weight (and reduced handling and braking performance) are more than made up for by the increased engine power. Besides with the wider, lighter chassis and improved power, thanks to the 7-liter LS1, the Corvette team gained ground in another area this past season.
At the level where the Corvettes and Vipers are competing, every race, including the 10-, 12-, and 24-hour endurance contests, is an all out sprint to the checkered flag. With that kind of intensity, even the smallest problem, mistake, or simple bad luck can separate the winner from the losers. And with that kind of intensity the skill and dedication of the crew can make all the difference in the world. Like an engine as it gets broken in or racing slicks as they get warmed up, the crew became more disciplined, more unified, and better in every measurement as they got more experience.