V8 could return to Mercedes-AMG C63, next E63 – report

Twin-turbo V8 power could return to the Mercedes-AMG C63 and next-generation E63 within three years amid backlash towards the planned move to downsized four- and six-cylinder engines, according to an overseas report.

According to respected European journalist Georg Kacher writing for US magazine Car and Driver, Mercedes-AMG is "considering" a backflip on the move to drop V8 engines from the C63 and E63 in favour of plug-in hybrid systems based on smaller engines.

The new C63 in Australian showrooms imminently is based around the 2.0-litre four-cylinder from the A45 hot hatch – to much controversy – while the report claims the next E63 will use an inline six-cylinder engine.

"Two independent sources" cited by Car and Driver claim the return of the 4.0-litre ‘M177’ twin-turbocharged V8 used in the outgoing C63 and E63 is under consideration for 2026 – possibly with plug-in hybrid assistance.

Mercedes-Benz is said to be developing a version of the engine compatible with Euro 7 emissions standards – billed as some of the strictest new-car emissions rules ever devised globally – due to come into force in Europe in 2025 or 2026.

The V8 is currently offered with plug-in hybrid power in the AMG S63 E Performance and GT63 S E Performance super sedans, where they produce up to 620kW with the engine and electric motor combined.

Car and Driver – citing “senior engineers directly involved in the matter” – claims the C-Class and E-Class need “only minor bodywork changes” to fit the larger V8 engine, plug-in hybrid battery and electric motor, and “auxiliary equipment”.

The publication speculates the new V8-powered AMG versions could remain in production “well into the next decade” if plans to extend the life cycle of the current C-Class and E-Class – which would typically have a seven-year lifespan, and be due for replacement in 2028 and 2030 respectively – are green-lit internally.

Some sources online have cast doubt over the ability for the latest C-Class to house a V8 as it has been developed exclusively for a four-cylinder – and a wider ‘V’ engine may be too large to fit.

Meanwhile the new E-Class has been engineered to fit both an inline four-cylinder, and a V6 engine from launch in non-AMG form.

The claim that there will even be a new E63 – irrespective of what is under the bonnet – has caught some industry analysts by surprise.

Reports from German publications over the past six months have claimed there are no plans for such a vehicle, and the new flagship AMG performance version of the latest ‘W214’ E-Class may become the E53 – powered by an inline-six engine with mild-hybrid, or modest plug-in hybrid assistance.

The first prototypes for the new four-cylinder hybrid C63 were photographed testing in production-ready bodywork in Europe in October 2020, about two years before the vehicle was unveiled last September.

No images have been captured of an AMG E63 testing – distinguished by the squared-off quad exhaust tips synonymous with top-of-the-range AMG ‘45’ and ’63’ cars – even though the regular E-Class has been unveiled.

This timing would suggest a new E63 – if the Car and Driver report is accurate, and such a vehicle is planned – is at least two years away, particularly if it is testing a new inline-six plug-in hybrid system that has not been applied to any previous AMG vehicle, and therefore may require additional on-road development time.

It is unclear where this report leaves the CLE – the new coupe and convertible intended to succeed both the previous-generation C-Class and E-Class two-doors – which is slated to use a mild-hybrid turbo inline-six in the CLE53, and a plug-in hybrid with four or six cylinders in the CLE63.

Car and Driver claims the decision to revive the V8 in the C63 and E63 is intended to better fight its German rivals.

BMW has committed to larger engines in its performance cars – the current M3 uses a twin-turbo inline-six with no hybrid technology, while the next M5 is set to be a twin-turbo V8 plug-in hybrid – while the report claims Audi is planning a “V6 hybrid” with up to 477kW for the next RS5 and RS7.

Today’s Audi RS5 and RS7 are exclusively five-door ‘Sportbacks’ (liftbacks) but the new models will add wagon body styles, as the new name for the models known currently as the RS4 and RS6.

It would not be the first time a Mercedes-Benz E-Class has been re-engineered to fit a larger, eight-cylinder engine.

In 1989 Mercedes-Benz commissioned Porsche to rework the chassis and suspension of the then-current ‘W124’ E-Class to fit the 5.0-litre V8 from the SL roadster, to create the now-iconic 500E.

It was found the car’s new wheel arches were too wide to fit down the Mercedes-Benz production line in Sindelfingen, Germany, so Porsche – which was facing declining sales and financial challenges at the time – was commissioned to build the vehicle, from 1990 to 1995.