With most modern European makes fitting their cars with 2.0-litre turbocharged 4-cylinder engines these days, the crown for the most powerful unit in series production goes to Mercedes-AMG.
Its new M 139 2.0-litre turbocharged 4-cylinder engine, destined for the AMG 45 models, makes 416 hp (up 40 hp) and 500 Nm (up 26 Nm) of torque. Those are the figures for the “S models”, the base model makes 382 hp and 479 Nm instead.
Maximum boost pressure is set at 2.1 bar (1.9 for the base model), while engine speed is capped at the 7,200 rpm.
Unlike the old M 133 engines, the new power plant is now rotated by 180 degrees in the engine bay which means the turbocharged and exhaust manifold is positioned at the back of the engine bay, with the intake system sitting behind the front grille.
This allows for improved air flow with shorter distances and fewer diversions – both on the intake and exhaust side. The new engine position also allows engineers to design the flattest and most aerodynamic front end.
The new twin scroll turbocharger incorporates roller bearings for the first time for the turbine’s shafts – reducing mechanical friction – allowing it to build boost quicker which in turn improves acceleration.
With more power comes more heat so fresh air is now also used, in addition to water and oil, to cool the turbocharger with fresh air directed to the turbine through the radiator grille.
Along with an electric water pump that works independently regardless of engine speed, there’s also an additional radiator in the wheel arch that supplements the larger unit by the front grille.
Assembled by hand, the new engine is built on a newly designed production line that’s been improved for better ergonomics and efficiency.
Each assembly technician is followed by a driverless transport system. Its shopping cart has precisely the components needed to complete the engine being assembled.