Mercedes-Benz reveals 300kW-plus electric-turbo six

Mercedes-Benz has revealed a BMW-rivalling 3.0-litre in-line turbo six-cylinder with an Audi-challenging electric compressor to eliminate lag and make beyond 300kW/500Nm.

The potent straight six is part of a new modular engine family with 500cc capacity per cylinder, which will spawn a 200kW 2.0-litre twin-scroll turbo four likely for the next A250, and a 350kW/700Nm 4.0-litre twin-turbo V8 for larger sedans.

All utilise a 48-volt electrical system that uses brake energy regeneration and a mild-hybrid capacitor function to activate the alternator and water pump electrically, taking the load of the engine. But only the turbo-six provides a compressor that can electrically spool up its turbocharger to eliminate lag and provide instant boost, at least for now.

A similar system is used in the Audi SQ7, but it teams an electric turbo with a 4.0-litre V8 engine to make 320kW and 900Nm.

The Benz six is said to reduce CO2 emissions by 15 per cent compared with the outgoing twin-turbo V6 of the same capacity, which in the Mercedes-AMG C43 and E43 makes 295kW and 520Nm.

The in-line replacement will be more powerful and potentially torquier, and along with the new twin-turbo V8 that gets cylinder deactivation technology to save fuel, will debut in a facelifted S-Class limousine range later this year.

It will no doubt follow in C-Class and E-Class models to challenge BMW’s in-line six hegemony, the gruntiest of which develops 331kW and 550Nm in the BMW M3 and M4.

But it’s the 240kW/450Nm BMW 340i that Benz will target the new engine at, in addition to the Audi S4 makes 260kW/500Nm from its 3.0-litre turbo V6. And with beyond 300kW and over 500Nm, the new C-Class, E-Class and S-Class straight six should really make a mark.