Chevrolet teases Z06, glorious flat-plane V-8 noises ensue

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Chevrolet

We’ve seen spy photos and heard the sound of the upcoming Corvette Z06’s exotic new engine, courtesy of third parties, but today we got our first taste directly from Chevrolet.

The short video doesn’t give us much, just a few revs of the rumored 5.5-liter flat-plane-crank V-8 that’s supposed to be based on the C8.R’s high-revving mill of the same displacement. The video shows a race track from the car’s perspective as it transitions to the street, highlighting that race-developed powertrain.

There are still plenty of questions remaining about this elusive powertrain, though. Chevrolet kept the C8.R’s engine under cover during its race debut at the 24 Hours of Daytona in 2020, and 18 months later there’s still little known about the race engine—or its production counterpart.

chevrolet c8 corvette z06 front three-quarter camo spy shot
Spy shot of the Z06, which could arrive for the 2023 model year. SpiedBilde/Brian Williams

Aside from recent news of the Corvette’s LT2 getting a fuel injection update for 2022, powertrain information from team Corvette has been sparse. The LT2, still producing 490 horsepower in standard configuration and 495 hp with the performance exhaust, will get higher-pressure direct injectors to clean up emissions and improve fuel economy slightly. Perhaps that was something learned from the C8.R that has trickled down into the production Stingray before we see a similar fuel system in the Z06?

As of now, the Ford Mustang GT350’s 5.2-liter Voodoo engine is the largest-displacement flat-plane-crank V-8 that made it to a production car. Unlike traditional V-8s that use a cross-plane design, flat-plane V-8s experience secondary vibrations that can literally shake fasteners loose. The benefit of a flat-plane crank is that it allows for a firing order that is evenly distributed between the two banks of cylinders, with 180 degrees of crank rotation between power strokes on a given bank. That makes it possible for each exhaust manifold to be carefully tuned to increase scavenging and boost volumetric efficiency. In contrast, a cross-plane V-8 will always have two cylinders from each bank firing just 90 degrees apart. That arrangement gives the wonderful burble loved by small-block and big-block fans alike, but it’s not quite as efficient unless you get really creative with the exhaust primary routing. Ford’s GT40, shown below, used the infamous “bundle of snakes” exhaust to move exhaust primaries from one side to another in order to get four-into-one collectors each with four cylinders that were 180 degrees apart in the firing order.

Ford GT40 Mk II Engineer at work
Ford

Chevrolet says it will reveal the details of the Z06 this fall, which hopefully include a deep dive into the engine and an explanation of how Chevrolet managed to build a production flat-plane crank V-8 with such a large displacement. Does it use exotic materials? Or perhaps a new type of balance shaft? Until we get the real details we’ll be speculating and bench-racing this new track-focused Corvette against all sorts of its exotic mid-engine competition, which in just about every instance should cost several times as much as the Z06. Once again, America’s sports car is shaping up to be an outrageous performance bargain.

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