Mercedes-AMG to boost in-line sixes with electric turbos

MERCEDES-AMG is readying a potent new in-line six-cylinder performance engine that will usher in the ‘53’ moniker to replace models such as the C43 and E43.

Based on the M256 3.0-litre in-line six-cylinder that arrives in the updated S-Class later this year, the AMG-fettled version will boost outputs to about 330kW, a healthy advance on the 295kW peak of the recently released, twin-turbo V6 E43 AMG.

Key to the new engine is an electric compressor, or turbocharger, which Mercedes-Benz dubs with the German acronym eZV.

Described as an ‘auxiliary’ compressor, the electric turbo seems certain to mzimic the operation of the unit fitted to the 4.0-litre V8 diesel in the Audi SQ7 and Bentley Bentayga, boosting airflow at low speeds, therefore eliminating turbo lag while a conventional exhaust-gas-driven turbo reaches its optimal operating speed.

As well as engine management software and the exhaust system, AMG is likely to focus its efforts on that gas-driven turbo as a means to boost outputs over the regular engine.

As for the name for models fitted with the M256 six-cylinder, AMG boss Tobias Moers is refusing to say – “we’re going to continue with 43s, but I don’t talk about nomenclature right now” – but Wheels has learnt Mercedes-AMG will replace its 43s with 53s, not only separating the basic layout but also the fact the new engine has more power than the V6 it will replace.

Crucially, it also positions the in-line six used in the larger vehicles with a longitudinal engine layout ahead of the four-cylinders that utilise the ‘45 AMG’ moniker.

Moers said even as AMG prepared itself for electrification, there would be big investments made in developing the internal-combustion engines that are a crucial component of a hybrid system.

“Chasing more efficiency out of combustion engines is mandatory,” said Moers.

As for a hybrid version of the six-cylinder, Moers is refusing to go into details, except to say AMG is prepared.

“We are well prepared regarding both our strategy and volume.”

Next Mercedes-AMG A45 to have more than 300kW

He added that the AMG hybrid strategy would utilise the electric motors all the time.

“When we have an electrified powertrain it should be always functioning … especially regarding performance.”

The move to an in-line six-cylinder engine has little to do with heritage and a lot to do with saving money.

Utilising the architecture of the next-generation M264 four-cylinder engine, the M256 has an identical cylinder design and even shares a modular exhaust system.

It means one of the most expensive components of an exhaust – the catalytic converter – can be amortised across the four- and
six-cylinder models.

It also means engineers only need to create one perfect 0.5-litre combustion chamber, which is then replicated across the configurations.