Drivers of the new Z06 will be enticed to screw the tachometer needle to a dizzying 8,600 rpm, courtesy of an all-new flat-plane crankshaft design utilised in the new Corvette Z06 engine. This new 5.5L DOHC V-8 engine for the 2023 Z06 signals a return to natural aspiration for Corvette’s track-ready performance vehicle. This new power unit replaces the C7 Z06’s 6.2 litre, supercharged LT4 powerplant.
Chevrolet Powertrain Engineering prioritised engine responsiveness and trackability, two hallmarks of naturally aspirated engines, in order to provide a compelling driving experience. As a consequence, it was decided that a completely new normally aspirated engine would be developed, with a target performance higher than any other naturally aspirated production V-8 engine ever built. This engine can turn to the high rpms required to generate the desired power due largely to a lightweight, flat-plane crank configuration.
The new Corvette Z06 engine is intended to complement all elements of the Z06’s track-focused performance experience, not just horsepower. This engine exudes a whole new and dramatic character, from its 8,600-rpm redline and full racing-style dry-sump oiling system to expertly tuned induction and exhaust systems. Engineers worked for two years to create a unique, rich exhaust tone unlike any other Corvette has ever produced.
The core to the LT6’s performance is a low-inertia rotating assembly based on an all-new flat-plane crankshaft that, along with a short stroke (the distance each piston assembly travels from the bottom to the top of its stroke), enables the engine to rev to its designed peak.
A variant of the LT6 has powered Corvette Racing’s C8.Rs since they started competing two years ago. The engine’s performance and durability have been tested and refined thanks to the demands of their involvement in endurance racing.
The LT6 engine has a bore & stroke of 4.104 x 3.150 inches / 104.25 x 80 mm, making a capacity of 5.5 litres, a compression ratio of 12.5:1, intake valve size of 1.654 inch / 42 mm and exhaust valve size of 1.378 inch / 35 mm, and has a firing order of 1-4-3-8-7-6-5-2.
The following are the other LT6 highlights as defined by Chevrolet:
- All-new aluminium cylinder block casting with the Small Block engine family’s signature 4.4-inch (111.76 mm) bore spacing
- All-new dual-overhead-camshaft cylinder head design with fully CNC-machined combustion chambers and intake ports, supporting a mechanical “finger follower” valvetrain
- Dual-coil valve springs to support titanium intake and sodium filled exhaust valves
- Four valves per cylinder – two intake and two exhaust
- Forged aluminium pistons and forged titanium connecting rods for low mass and high strength
- Distinctive Edge Red camshaft covers
- All-new active split intake manifold with twin 87 mm throttle bodies
- All-new six-stage dry-sump oiling system with individual crank bay scavenging
- Four-into-two-into-one stainless steel exhaust headers
- 670 hp (500 KW) at 8,400 rpm (GM tested per SAE J1349)
- 460 lb-ft (623 Nm) of torque @ 6300 rpm (GM tested per SAE J1349)
Specialist engine builders, at the Bowling Green Assembly Plant in Kentucky’s Performance Build Centre, individually hand-assemble each LT6 engine. To achieve Chevrolet’s exacting specs for the LT6, master engine builders utilize precision tooling and fixtures to manually install each engine component. To celebrate the builder there is a plaque on the intake manifold of each LT6 engine with the name and signature of the technician who completed the assembly.