Mercedes-AMG details 416-hp turbo four

It will power the firm's next-generation 45-badged compacts.

Mercedes-AMG has detailed the turbocharged, 2.0-liter four-cylinder engine that will power its next round of high-performance compact models. Called M139 internally, it will be manufactured in Affalterbach, Germany, following the firm's "one man, one engine" philosophy.

The M139 will power the upcoming 45-badged variants of the, the A-Class, the GLA, and, possibly, the GLB. It makes 382 horsepower at 6,500 rpm and 354 pound-feet of torque from 4,750 to 5,000 rpm in its standard state of tune, but the firm will offer a variant of it with 416 horsepower and 369 pound-feet of torque on tap. The high-output version boasts 208 horsepower per liter of displacement, and it reaches its red line at 7,200 rpm.

AMG promises its new turbo four delivers immediate response; it feels like a naturally-aspirated engine, the firm brazenly wrote in a statement. The turbocharger delivers up to 2.1 bars of boost, and it spins at up to 169,000 rpm. It's not all about forced induction, though. The crankcase is made out of aluminum to save weight, for example, and the engine is tilted by 180 degrees towards the firewall to make the intake and exhaust systems as direct as possible.

Reliably squeezing 416 horsepower from a four-cylinder engine requires a sophisticated cooling system. It consists of a main radiator up front, a second, smaller radiator in one of the front wheel arches, and an electric water pump.

We expect to see the first 45-badged AMG model powered by the M139 engine during the 2019 Frankfurt auto show. It will likely be the A-Class hatchback sold in Europe, though we may see the A-Class sedan available in America and/or the hot-rodded CLA there, too. Sales will begin before the end of the year. Buyers will be able to choose between the 382-horsepower A45, and the 416-horsepower A45 S, a strategy that mirrors how AMG sells its V8-powered 63 models.