Deep Dive: The V8 in the 2023 Chevrolet Corvette Z06 is the most powerful naturally aspirated production V8 engine ever built

The 2023 Chevrolet Corvette Z06 debuted earlier this week with some impressive features, including its most powerful naturally aspirated V-8 engine to date. Engineer Jason Fenske takes a deep dive into this 5.5-liter V-8 engine and compares it to the supercharged engine in the previous Z06. [Codenamed LT6, the C8 Z06 engine produces 670 hp at 8,400 rpm and 460 lb-ft of torque at 6,300 rpm. It features double overhead cams, dry sump lubrication, and a flat-plane crankshaft. It can also rev to 8,600 rpm, at which point it roars more like an Italian supercar than an American muscle car.

The horsepower figure is notable because it surpasses the 6.2-liter supercharged LT4 V-8 engine found in the previous generation C7 Z06. This engine was larger and boasted forced induction, but had a maximum output of 650 hp at 6,400 rpm.

No top speed figures have been confirmed, but Chevrolet spokesman Trevor Tompkins told Motor Authority that the 0-60 mph time would be 2.6 seconds.

Indeed, the LT4 has 650 lb-ft of torque at 3,600 rpm, but Fenske noted in the comments section of the video that the difference is made up by the gearing: the final drive ratio of the 2023 Z06 is 5.56:1, compared to 2.41:1 for the conventional Z06.

Regardless, the LT6 V-8 engine is a great engineering feat. Horsepower is largely limited by the amount of air that can be packed into the engine, but this engine can only take in air at atmospheric pressure, Fenske noted.

Fenske also points out some interesting details, such as the hollow camshaft (to reduce inertia) and dual valve springs (for more precise valve control). Cam lobes also act directly on the finger follower without hydraulic pressure, providing more direct valve motion. The lack of hydraulics usually requires periodic valve lash adjustments (the gap between the rocker arms and the top of the valve stem), but Chevrolet has eliminated the need for such adjustments by installing precision-engineered shims at the factory, Fenske says.

Chevrolet also placed the direct fuel injectors on the exhaust side rather than the intake side. The intake manifold was designed with Hemholtz resonance in mind. The term describes a wave of air pressure that produces a grating sound when the car windows are opened, or in this case, maximizes torque output.

The entire video is definitely worth watching as there is a helpful explanation of the engineering terminology in more detail.