The World’s Most Powerful Production Four-Cylinder Is An Engine Everyone Loves To Hate
Did anyone else grow up feeling like AMG could do no wrong for the last quarter-century or so? It’s as if every time the performance wing of Mercedes-Benz set out to build something, it turned out to be a banger no matter what it was. Well, even the best have to slip up every once in a while, as if to remind the masses that, yes, indeed, they are still human. Even so, by the standards of a screw-up, what AMG managed to do just recently is up there with one of the worst this century.
The AMG Way: Building Engines Like Nobody Else Can
For as long as AMG’s been a dedicated manufacturer of high-performance Mercedes-Benz platforms, the firm had a very distinct and altogether unique way of building engines. In most engine assembly lines, the production process isn’t all that different from the car it’s bolted into. The bare block starts at one end of the line, and a slew of different workers assemble each component until it is ready for installation into the car.
To put it lightly, AMG found this method to be, well, a little lackluster. Instead, their philosophy involved a simple premise: one man, one engine. At one of their two main production hubs in Affalterbach and Kölleda, one master technician is responsible for the complete assembly of an engine from the bare block to the heads, the accessories, the ancillaries, and everything in between. This way, there’s no ambiguity between what one tech’s done to an engine five minutes ago versus what another one does right after their lunch break. Make no mistake, it takes far longer to get the job done this way, but the results really do speak for themselves.
That borderline obsessive dedication to craftsmanship resulted in some of the greatest engines built in the last half century. Icons like the M156 (the original all-AMG engine), the M113K V8 in the R230 SL55, the M113K supercharged V8 in the W211 E55 AMG, the naturally aspirated M159 V8 in the SLS AMG, and the M120 V12 in a whole range of Pagani supercars. In truth, AMG’s made more amazing engines than can be realistically listed in one place. Yet, so far as many are concerned, over three decades of excellence culminated with two engines in particular. Two so powerful, so happy to rev, and so joyous when you put your foot down, that replacing them seemed almost impossible.
The M177: Pretty Darn Close to Automotive Perfection
In truth, the 4.0-liter twin-turbo V8 in the W205 C63 AMG and a whole slew of other cars wasn’t the only engine replaced by something everybody hated. The 3.0-liter twin-turbo V6 you’d find in the SL 43, GT 43, and the GLC 43 AMGs also fit the bill. And yet, there was a certain magic, an inalienable feeling that AMG had stumbled upon perfection, that permeated every cubic centimeter of an M177’s construction. Its high-pressure direct-injection system, hot-V turbocharger arrangement situated inside the twin cylinder banks, and forged steel crankshaft came together to make 504 horsepower and 516 lb-ft of torque.
Sure, it doesn’t sound like all that much power by modern standards, outrageous as it would have sounded just 20 years ago. Yet, it was how the M177 delivered said power that people raved about. With an imperceptible level of turbo lag and a boisterous, smooth power delivery all the way up to the redline, the M177 was loud, mean, and embodied everything that made a well-sorted German sports car so desirable. Along with the C63 AMG, the larger W213 E63 and W222 S 63 also used the M177, as did the AMG GT Coupe (in dry-sump form as the M178), the Aston Martin DB11 and DBX, plus the Valhalla, heavily modified, in conjunction with an electric motor.
By all accounts, the M177 and its related variants were a historically brilliant family of engines. It’s exactly why the follow-up, by all accounts, made people’s blood boil at worst, or made people pity AMG’s engineers at best. Suffice it to say, even the world’s most powerful four-cylinder engine ever put in a road car wouldn’t suffice by a long shot.
The M139L: The World’s Most Powerful Four-Pot, But Who Cares?
Let’s set the scene. The year is 2022, global OEMs are scrambling to adapt to an all-electric revolution they were absolutely certain was imminent. In short, they all believed that sticking to big V8s was a surefire way to get fined or regulated out of existence. Around the same time AMG is gearing up to replace the W205 C63’s internals and generally refresh the entire car. Knowing the European Union was waiting just off-camera with a proverbial “piece” to AMG’s head, another V8 was pretty much out of the question.
Knowing this, the W206 C63 S E-Performance was born, and the public reaction was far from warm. Under its hood was an engine which, on paper, AMG had every reason to be proud of. With just two liters of displacement, AMG used clever technology, including an electrically assisted exhaust-gas turbocharger with an electric motor built into the turbo shaft, plus a rear-mounted PSM unit with a peak boost output of 201 hp, to combine for 671 hp in total. Combined with 752 lb-ft of near-instantaneous torque, it sounds like a formidable powertrain. It probably would have been, had the car it was mounted in been a Civic Type R or something comparable.
Under the hood of a form factor historically synonymous with a V8, seeing a hybrid four-cylinder under that same hood felt deeply incongruous. The point? It didn’t matter how amazing the M139L was, or how much faster the C63 S E-Performance was than its predecessors. With roughly 800 pounds more weight to contend with, the handling suffered, the power delivery felt clinical, and the whole package lacked anything close to a genuine soul. Journalists panned it, buyers grumbled, and Mercedes dealers the world over became impromptu holding pens for AMG-branded four-cylinders that, in all honesty, almost nobody wanted. It was a failure no amount of F1-derived engine tech could fix. Ultimately, eight cylinders in a V formation cannot be replaced by electric tinsel.
Where to Go From Here?
That electric revolution for which a four-cylinder hybrid was supposed to be a stepping stone never wound up materializing. At least it never came for sports cars the way AMG was sure it would just a few years ago. With this in mind, you won’t be surprised to know the firm is actively in the process of reversing course, promising to never again shove a hybrid four-cylinder under the hood of its flagship vehicles. A strong focus is being placed on six-cylinder engines in non-V8 models, likely with twin turbos, and with only the mildest hybrid systems assisting them.
Better still, in May 2026, AMG CEO Michael Schiebe confirmed in an interview with carmagazine.co.uk that a new 4.0-liter twin-turbo V8 was in the works, au naturel, and it’s expected to remain in production from launch until at least 2035. That’s a full five years past when most folks figured European roads would be fully electrified. It’s a disappointment for the environmentally conscious, but a welcome sign for those who would rather make lifestyle concessions for the environment than trade in their beloved V8s.
Source: carmagazine.co.uk, Mercedes-Benz
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