Back in the days of the C5, the late John Lingenfelter was able to get a Corvette up to 225 mph with “only” 650 horsepower. By the time the C6 ZR1 rolled into production, it was able to achieve “only” 205 mph with 638 horsepower. With cars that are pumping out similar power figures, why the top speed discrepancy?
It comes down to aerodynamics. The 2000 Lingenfelter Twin-Turbo Corvette Stage II had “no external changes” as the video below says. From the outside, at least, this was a stock C5, which means this car benefitted from the stock C5’s exceptionally slippery 0.29 drag coefficient. The C6 ZR1, with its fancy ground effects and greater appetite for cool air, achieves a drag coefficient of 0.36; in other words, it’s the brick in this comparison.
In a rough sense, that’s the difference a cd of 0.07 can have on top speed. Of course, gearing is also an important factor in top speed. No information is given about the gear ratios of the Lingenfelter car, but my money says it wasn’t running a stock setup — a standard C5 is rated for 285 mph in sixth gear; a 2009 ZR1 is rated for 224 mph in sixth. It’s likely Lingenfelter’s car was running ratios similar to the ZR1 in order to blow 25 mph past 200.
Going into the discussion of which car is more stable above 200 mph, hands down, it’s the C6 ZR1, but as we can see from the difference in top speeds, more stability costs mph, which is worth it when you are traveling fast enough to vaporize on impact.