Mercedes’ mad new turbo-four can make even more power than we thought

We recently went into great detail about Mercedes’ new M 139 2.0-liter four-cylinder engine, the power plant that will make the new 2020 Mercedes-AMG A45S the fastest and maddest hot hatchback ever created. The automaker has announced the engine makes 415 horsepower (421 PS), or around 40 horsepower more than the similar unit it replaces. However, a new report has surfaced suggesting this crazy force-fed four-banger has even more to give and Mercedes has every intention of getting it to achieve its full potential.

Wait, can the Mercedes-AMG M 139 engine pack even more grunt?

Because apparently 208 horsepower (211 PS) per liter just isn’t enough, Australian outlet Carsales.com tells us it has information there’s even more power to be extracted from the M 139. It points to a press event held by Mercedes for US, British, and Aussie journalists where the boss of AMG’s engine development program, Ralph Illenberger apparently confirmed there was “room for improvement” regarding the power output of the M 139, even though “421hp is really quite a high number, especially when it’s also street-legal.”

Think 416 Horsepower From AMG's M 139 Four-Banger is Crazy? Mercedes Says It Can Do Better
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The most powerful 2.0-liter ever fitted to a production car (albeit a very limited production model) was the four-pot that powered the 2014 Mitsubishi Lancer Evolution X MR FQ440. As you can tell by its exceedingly lengthy name, it was a limited edition special version affair and while it did make the advertised 440 horsepower, it really was a bit too laggy to be enjoyable to use as a daily driver, plus its 4,500-mile (around 7,200 km) service interval made it a bit of a chore to own and maintain.

That’s why even the current 415 horsepower output is no mean feat on Mercedes’ part. The M 139 should be able to take 250,000 km (155,000 miles) without requiring a rebuild, according to the manufacturer, and that is an impressive feat given the level of boost that’s being pumped through it in order to achieve its mad performance numbers.

Mercedes-AMG M 139 2.0 litre turbocharged four-cylinder engine specifications
Displacement 1991 cc
Bore x stroke 83.0 x 92.0 mm
Output 310 kW (421 hp) at 6750 rpm (S-model) 285 kW (387 hp) at 6500 rpm (basic version)
Peak torque 500 Nm at 5000-5250 rpm (S-model) 480 Nm at 4750-5000 rpm (basic version)
Max. engine speed 7200 rpm
Compression ratio 9.0:1
Turbocharging One twinscroll turbocharger with roller-bearing compressor and turbine wheels
Max. charge pressure 2.1 bar (S-model) 1.9 bar (basic version)
Mixture formation Combined direct and manifold injection. 1.) Third-generation multiple direct injection. Fast and precise piezo injectors spray the fuel into the combustion chambers at high pressure 2.) Additional intake manifold injection with solenoid valves
Cylinder head Two overhead camshafts, 16 valves, adjustable intake and exhaust camshafts, CAMTRONIC valve timing adjustment for the exhaust camshaft
Max. air mass throughput 1,200 kg/h (S-model) 1,100 kg/h (basic version)
Engine weight (wet) 160.5 kg

But what would Mercedes power with this even more powerful version of the M 139? Well, maybe something along the lines of a Mercedes-AMG A45 R (in current Merc lingo, a model that is branded “R” is even faster than one that bears an “S” badge which in turn is faster than the base model that has no additional letters after its model designation).

Think 416 Horsepower From AMG's M 139 Four-Banger is Crazy? Mercedes Says It Can Do Better
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An even more powerful Mercedes-AMG M 139 engine could suit the C-Class

Think 416 Horsepower From AMG's M 139 Four-Banger is Crazy? Mercedes Says It Can Do Better
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It would also make sense to use such an engine to power a rear-wheel drive car, like the C-Class. Its main benefit would obviously be its lighter weight compared to the six- and eight-cylinder engines of larger displacement that are usually required to make close to 450 horsepower. This should not only make the car fast in a straight line, but also help improve its agility and cornering capability. I think that even if Mercedes doesn’t have such a model planned for the current generation C-Class, there’s no reason why this M139 engine (or a future development of it) couldn’t make its way under the hood of a future C45S, based on the next-gen C-Class due around the year 2022 - 2023.

Further reading

2019 Mercedes-AMG A35 Exterior
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Read our full review on the 2019 Mercedes-AMG A35.

2018 Mercedes-Benz A-Class Exterior
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Read our full review on the next generation 2018 Mercedes-Benz A-Class.

2014 Mercedes-Benz A45 AMG High Resolution Exterior
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Read our full review on the previous 2014 Mercedes-Benz A45 AMG.

Source: Car Sales

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