Mercedes-AMG to return to V8 power with upcoming CLE 63

Mercedes-AMG will return to V8 power, confirming an all-new mild-hybrid petrol engine will debut in the upcoming CLE 63 later this year.

The move marks a shift away from the controversial four-cylinder plug-in hybrid drivetrain introduced in the current C63, which failed to gain traction with customers, leading to a significant drop in sales for one of AMG’s best-selling models. 

Sources within the German brand have told Autocar that following the CLE 63, the V8 will be rolled out to other models, including a revised C63 due in 2026.

Full details of the new engine remain under wraps, but it's rumoured to lean heavily on AMG's existing twin-turbocharged 4.0-litre V8 architecture. 

While the V8’s previously mooted return has been confirmed, it comes with a significant engineering change: AMG has abandoned the traditional cross-plane crankshaft in favour of a flat-plane design.

This promises to improve throttle response but will sacrifice the deep, burbling soundtrack traditionally associated with AMG V8s.

This layout, first adopted by AMG on the GT Black Series’ M178 LS2 engine in 2021, also enables a more compact crankcase design, allowing AMG to package the new engine into models that weren't originally engineered for a V8, including the fifth-generation C-Class.

It also provides the scope for a higher redline and ignition cut-out.

In its ultimate form, the new V8 is expected to receive a mild-hybrid system with an integrated starter-motor within the gearbox for added power boosting and greater efficiency.

The current C63's electronically turbocharged 2.0-litre four-cylinder engine, in combination with a rear-mounted electric motor and a 6.1kWh lithium-ion battery, produces 671bhp and 752lb ft of torque.

Despite those impressive figures, the shift from a traditional V8 to a four-cylinder PHEV drivetrain was widely criticised, particularly for the lack of acoustic character. 

By comparison, the previous-generation C63 S, equipped with AMG’s cross-plane twin-turbocharged 4.0-litre V8 in M177 specification, delivered 503bhp and 516lb ft of torque - less outright power but a far more engaging experience.

To compensate for the higher-pitched, more aggressive sound of the flat-plane crank V8, AMG plans to provide future models with an artificial sound generator to simulate the burbling soundtrack of its most celebrated models.

Beyond the new V8, AMG is set to introduce greater design differentiation between its lower-end and top-of-the-line models within each market segment.