Yahoo Autos Tested: 2023 Chevrolet Corvette Z06 Convertible
From the November 2022 issue of Car and Driver.
Around here, we sit through a lot of presentations about automotive trends. Charts and speeches detail the long-term march to electrification and how the move toward small-displacement, turbocharged engines is bridging the gap until we get there.
We hear boasts about platform sharing and production efficiencies realized. What no company ever says is, "You know what we decided to do? Draw up a big-ass V-8 that revs to a million and will only go in one version of one model. We'll build it by hand, and pretty much not a single part will be compatible with anything else. It'll have way less torque than its predecessor, and it'll get worse fuel economy. But nobody will care because it'll sound so righteous at 8500 rpm that you'll forget your own name." We might be paraphrasing a little, but that essentially is Chevy's pitch for the 2023 Corvette Z06 and its singular LT6 V-8. We can't believe General Motors actually built this thing, and maybe neither can GM.
Chevrolet could have powered the new Z06 with an evolution of its supercharged 6.2-liter V-8, which made as much as 755 horsepower in the previous-generation Corvette. That would have been easy and effective, the obvious move. Instead, engineers started from scratch on a naturally aspirated 5.5-liter screamer with a flat-plane crankshaft and 32 valves. At a heady 8400 rpm, the LT6 generates 670 horsepower the all-natural way, and it makes its 460 pound-feet of torque at 6300 rpm, nearly the redline in a regular Stingray.
From the moment the engine barks to life, it sounds impatient, its ragged flat-plane idle suggesting a pit stall at the Rolex 24 at Daytona or perhaps a pair of Suzuki Hayabusas sitting at a stoplight. While the Stingray's pushrod LT2 V-8 uses bimodal muffler valves—loud or quiet, a binary decision—the Z06's muffler valves can continually adjust in two-degree increments, fine-tuning the sound. Wide open, it sounds like a Ferrari 458 Italia that hit puberty. An engineer told us that during testing at the Nürburgring, the Z06's wail could be heard all the way around its lap. The Nürburgring, we should point out, is almost 13 miles long.
The LT6 was code-named Gemini during development, but not as an homage to the Chevy Gemini sold in South America in the 1980s and known hereabouts as the Chevrolet/Geo Spectrum. No, it's a reference to the moon-shot NASA program, because that's what this engine represents for the Corvette. There's a steep learning curve when your new V-8 is capable of 573 combustion events every second at the 8600-rpm fuel cut. If you're compiling a list of GM V-8 firsts, a lot of them from the past 30 years or so belong to the LT6. Dual throttle bodies and intake plenums. Fuel injectors on the exhaust side of the cylinders to aid high-speed air-fuel mixing. An 8500-rpm redline. The LT6 revs so fast that Chevy built in a mode to tranquilize the throttle when you're selecting the rpm for launch-control starts, lest you blow past your intended target by 1000 rpm. When we congratulated one GM engineer on the LT6, the response was, "Congratulate me if it still runs after 150,000 miles." Nevertheless, this engine has seen plenty of durability testing while powering the C8.R race car for two seasons.
We didn't put 150,000 miles on it, but we ran this Z06 70th Anniversary convertible plenty hard with nary a hiccup, and boy, did it put up some numbers. Its 2.7-second 60-mph time is a snapshot of a party that's just getting started, as evidenced by the Z06's 10.7-second quarter-mile at 129 mph. The Z06's short 5.56:1 final-drive ratio helps fire it off the line, but we'll be interested to see whether a car with the standard Aero package gets to, say, 160 mph quicker—this car wore the $8495 Carbon Aero package that helps generate 734 pounds of downforce at 186 mph, and those spoilers and underbody strakes exact a toll in drag at higher speeds. One clue on that front: Standard Z06s get a $2600 gas-guzzler tax, while cars with the Aero package are hit with a $3000 penalty. We averaged 12 mpg (the EPA city figure), making the 19-mpg EPA highway rating seem mighty optimistic.
Even though this particular car embodies a historically mellow Corvette spec—an automatic convertible—the Z06 structure is so stiff that the suspension calibrations match the coupe's. And on its Michelin Pilot Sport 4S ZP tires (275/30ZR-20 up front and comically monstrous 345/25ZR-21 in back), the Z06 pulled 1.12 g's on the skidpad and stopped from 70 mph in 144 feet. So go ahead and treat yourself to the droptop. You're not exactly trading performance for style, although you do miss out on gawking at the LT6. As with the Stingray, Z06 coupes display their engine under glass. Convertibles have a cover for the top mechanism that hides the engine, even with the convertible tonneau raised. As recompense, you're treated to an extra-loud serenade from the LT6 if you put the top up or down while the car is in motion (at up to 30 mph), since you're essentially driving with the hood open.
As with previous Z06s, this one is a holistic track-attack special, with plentiful chassis upgrades to take advantage of the newfound horsepower. The body is 3.6 inches wider than the Stingray's, making room for those huge tires and a wider track. The cooling system is upgraded with two extra heat exchangers, one of which is front and center and includes a removable grille panel to maximize airflow during track sessions. Six-piston brake calipers squeeze Brembo 14.6-inch rotors up front, and the rear end gets 15.0-inch rotors. The optional carbon-ceramic brakes ($8495) on our test car are even bigger—15.7 inches in front and 15.4 out back—and thoroughly indefatigable on a track. Put the car in Tour mode with the top down, gently blast some Gordon Lightfoot with the seat heaters blazing on a fresh fall evening, and it's easy to forget you're at the wheel of a hardcore track maniac, a car that can turn unapologetically sociopathic with the change of a couple of settings.
It recalibrates your expectations, the Z06. At first, 8500 rpm seems nutty, but soon enough you find yourself hitting the 8600-rpm rev limiter because it's pulling hard all the way there (the LT6 feels like it would be happy to visit the far side of 10,000 rpm, were it not for warranty considerations). There's so much lateral stick that you're almost surprised when it turns out to have limits, and the front and rear ends begin a dance to see who'll relinquish grip first. It's like the Z06 channels the high-winding spirit of the sixth-gen Z06, but with so much more sophistication. This is the Ferrari that Ferrari doesn't make anymore.
It's priced like it too, next to its Bowling Green brethren. This convertible carries a base price of $116,795, and options brought it to $162,510. The ceiling is higher if you care to explore the salutary effects of carbon-fiber wheels or treat yourself to the full Z07 Performance package. But what's the competition? An Audi R8 Spyder is probably the closest thing, and that costs even more and is down nearly 100 horsepower.
Corvette engineers could have built a forced-induction Z06 that was more powerful than this. That would have been easy. Instead, they chased a subjective experience, the howling mid-engine exotic fantasy we all carry in our heads. Against all odds, they made it real.
Counterpoints
Driving the new Z06 is a little like the scene in Talladega Nights when Will Ferrell shares the cockpit of his '69 Chevelle with a mountain lion. "If you're scared, that beautiful death machine will do what God made it to do—namely, eat you with a smile on its face." Leave the Z06 in Tour mode and it's almost as if there isn't a mountain lion in the car with you. Until you mash the accelerator. Then there are a dozen cougars roaring in the cockpit. —Jack Fitzgerald
It should be the fastest thing on earth, but it's only really, really fast. Then there's the ride quality: Do you need to pee? It's worse now. And, as in all eighth-gen Corvettes, the interior seems designed for divorcing couples—there's a wall between us emotionally, and also in the car. These days, most sports cars are grand tourers, but not the Z06. Wrestle it into submission. Let 'em hear you with the roar that precedes tornadoes. Every shift is a whip crack, like you're Indiana Jones. This is a bar fight on wheels. Your life has been too easy. Take on a challenge. —Elana Scherr
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