2023 Corvette Z06 arrives, packing world’s most powerful naturally aspirated V-8

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The rumors were true. The 2023 Chevrolet Corvette Z06 has finally been revealed at an event at the Petersen Automotive Museum, and it is indeed powered by a 5.5-liter flat-plane-crank V-8, a configuration shared with its C8.R brethren. The high-revving engine, teased over the course of the last several months, and then very prominently last week, revs to 8600 rpm and does so in quite a hurry. That fact really left no doubt as to the engine’s architecture, but we didn’t quite expect the new LT6 engine to crank out an absolutely gobsmacking 670 hp, making it the most powerful production naturally aspirated V-8 the world has ever seen. At this point, it may be the most powerful one we’ll ever see.

The 2023 Chevrolet Corvette Z06 is powered by the 5.5-liter LT6 engine, the highest horsepower naturally aspirated production V-8 to hit the market. Brandan Gillogly

Like previous iterations of the Z06, the track-focused package that dates back to 1963, it’s not all about power. The 2023 Z06 rides on the same chassis that the C8.R has used since its inception, giving the production car a head start when it came to tuning.

“Racing was the reason the Z06 was developed in 1963, and it continues to support development of the road models that make them better on the street and the track,” says Tadge Juechter, the Corvette’s executive chief engineer. “It also means we’ve tested the Z06 on the best tracks around the world, from Circuit of the Americas here in the United States to the Nürburgring in Germany.”

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To give the Z06 the added road grip necessary to make use of its 670-hp V-8, Corvette engineers added 3.6 inches to the track width compared to the Stingray, making it possible to fit steamroller-like 345-series rear tires. Michelin Pilot Sport 4S ZP tires are standard. The fronts measure 275/30ZR20 and are mounted to 20×10-inch wheels. The 345/25ZR21 rears are mounted to 21×13-inch wheels. Standard rims are an attractive set made from forged aluminum, with optional carbon-fiber wheels available only with the Z07 package. The carbon-fiber five-spokes shed 41 pounds of weight where it matters most, helping the suspension to plant the tires for optimum grip. The Z07 package also comes with Sport Cup 2 R ZP tires and a host of track-focused additions to make the most of every lap. They include a carbon-fiber aero package with a front splitter, front dive planes, a rear wing, and underbody strakes; FE7 suspension with Magnetic Ride Control 4.0; and Brembo carbon-ceramic brakes with 15.7-inch front rotors and 15.4-inch rear rotors. The aero package creates an impressive 734 pounds of downforce at 186 mph to glue the Z06 to the track surface and enable an absolutely astonishing 1.22 g of lateral grip.

“Virtually every component that distinguishes the Z06 was developed to support or enhance its capability,” says Juechter. “By leveraging the mid-engine architecture’s inherent advantages, we are able to achieve six percent more downforce than a seventh-gen ZR1 at eight percent lower drag.”

The standard Z06 uses a front splitter and a unique rear spoiler to provide 365 pounds of downforce at 186 mph. The optional Z07 package, shown here, offers just more than double, at 734 pounds. Chevrolet

Getting the Z06 back to its naturally aspirated roots is an all-new 5.5-liter DOHC LT6 V-8 engine that promises to be incredibly responsive and engaging. At its core is a unique aluminum block shared with no other production engine. The only thing it has in common with its small-block predecessors is its 4.4-inch bore spacing which was necessary to accommodate its rather large 4.1-inch bores. It uses lightweight forged pistons, a fairly short 3.1-inch stroke, and forged titanium connecting rods—something we haven’t seen on a Corvette since the C6 Z06’s LS7—to achieve a redline of 8600 rpm.

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Corvette’s engineers didn’t want to have a new Z06 that was less powerful than its predecessor and the 650-hp LT4 in the C7 Z06 set a high bar. To get maximum airflow from the four-valve heads, both the ports and the combustion chambers are CNC-machined. Intake valves are made from titanium, while the exhaust valves are sodium-filled to help deal with the extreme heat. The large twin plenums of the intake manifold use a pair of 87mm throttle bodies that operate in unison. There’s also a valve between the plenums, with three butterflies, that allows the two plenums to operate as one to help broaden the torque curve. Careful tuning of both the intake and the stainless steel tri-Y exhaust manifold allow the LT6 to make an impressive 460 lb-ft of torque at 6300 rpm and 670 hp at 8400 rpm. That broad powerband, combined with an eight-gear range, should make the Z06 an absolute monster on the track.

 

Like the C8 Stingray, the Z06 is available only with an eight-speed dual-clutch transmission. In this application, however, the final drive ratio is 5.56:1, up from the 5.2:1 available on Z51 Stingrays. That helps the Z06 get its LT6 into the kind of engine speeds where it’s happiest and spin up to launch from 0 to 60 mph in just 2.6 seconds. Don’t fret, though—at 5.5 liters, the LT6 still produces an ample reserve of low-end torque.

Like a road-going version of the C8.R, the C8 Z06 sets itself apart from the Stingray with almost entirely new body panels, though it does use the same roof as the Stingray. From the side, the most noticeable change is the wishbone-shaped trim that highlights the larger side air scoop. Aside from making it look purposeful, the extra width afforded by Z06-specific front and rear fascias and flared fenders also allow for more cooling air to enter the front and the side air vents. In the back, the four center-mounted exhaust tips are an immediate giveaway. Chevrolet noted that the tips are tuned to send engine noises forward to the driver. There’s no fake piped-in engine note here.

Inside the cockpit, Z06 drivers can opt for several leather, aluminum, and carbon-fiber trim options. The carbon-fiber interior trim package level 2 will include a carbon-fiber-wrapped steering wheel console, shift paddles, and console. When paired with the Adrenaline Red leather interior, shown above, the carbon fiber makes for a great contrast. All told, Z06 buyers will have 12 exterior colors, seven interior colors, seven wheel packages, six brake caliper colors, six seatbelt options, and two seat designs to choose from. The combinations should be more enough to make any crossed-flags aficionado—or first-time buyer—happy.

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With a bespoke mid-engine powerplant and a wider body, the Z06 erases whatever smudge of a line existed between Corvette and supercar. All signs point to this being the greatest driver’s car Chevrolet has ever produced and possibly the greatest production V-8 ever made.

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