Ray was also surprised by the results. He felt he had been faster in the ZR1—and he was, at least in terms of the speeds he reached between corners. As a result, the ZR1 demanded more of its brakes, suspension and tires in the corners. For example, while the Z07 got a little unsettled through Turn 7, the ZR1 threatened to become completely unglued. “I had a tail wag like I’ve never had there,” exclaimed Ray. While having the ZR1’s sophisticated Performance Traction Management engaged might have helped him carry more speed through this section—Corvette test drivers are faster with it on around the Milford Road Course—Ray felt more drastic measures were in order. “This car needs a wing!” he declared.
Apparently it also needs some work in the braking department: Ray experienced serious fade when hot on the binders coming into Turn 14. He was able to quickly get the pedal back, but this momentary lapse no doubt affected Ray’s confidence, and possibly the lap times he posted. (Ravel had recently had the car’s master cylinder replaced, after experiencing some braking irregularities. However, he and the dealer were confident that the problem had been resolved.)
Without the aid of full instrumentation and speed traps on the track, it is difficult to quantify the differences between these two Corvettes. From a seat-of-the pants perspective, however, Ray was able to succinctly differentiate the cars: “The Z07 was an easier 2:01.” With that in mind, he was quick to point out that more time behind the ZR1’s wheel would result in faster times. By contrast, he believes he didn’t leave much on the table with the Z07.
We were interested to find out Chevrolet’s take on the results of our comparison test, and contacted David Caldwell with GM Communications. “I’m not surprised to read of your experience,” he replied. “For lap times, yes, the Z07 approaches the ZR1. The margin really depends on the conditions, the driver and the sort of course; you guys had a bit smaller margin then we would expect.”
In his response, Caldwell also provided a rather revealing bit of information about the Z07/CFZ-equipped Z06. “It’s three seconds faster than a ‘normal’ Z06 at Milford, but a touch off the ZR1’s pace,” he explained. Three seconds is a huge chunk of time, especially considering the 2.9-mile Milford track is nearly the same length as Thunderhill. No wonder the Z07 posted such fast times.
On the road, it may be hard to justify the expense of adding a Z07 package to a standard Z06 (see sidebar), but on track, it is worth every cent of its $9,495 price tag. It would be hard to imagine leaving the CFZ Carbon Fiber Package off the order form. Its spoilers reduce aerodynamic lift and its lightweight roof panel offsets the added mass of the larger ZR1 wheels and brakes. Perhaps just as importantly, this options group imbues the Z06 with a racetrack-honed appearance we find irresistible.
How many customers will find this ultimate Z06 irresistible is another question. The hardcore track-day afficionados at which it is targeted will no doubt be tempted by the Z07, but their ranks are not legion. Ultimately, the decision will come down to a numbers game. In addition to coming very close to the ZR1 on track, our heavily optioned Z06 test car was hot on the heels of the supercharged Corvette in terms of its sticker price: $98,010. When faced with such a sum, we wouldn’t blame anybody for ponying up the extra ten grand or so required to buy a ZR1. After all, 638 is just plain more than 505.