Mercedes' Inline-Six Makes the Rest of Its Impressive New Motors Look Like Mechanical Plebs

Matt Posky
by Matt Posky

Mercedes-Benz is introducing a host of new engines with clever shared modular components, including a standard 500cc cylinder displacement.

These new engines include a new AMG-developed twin-turbocharged V8 for the S-Class and one of the most encouraging mechanical additions to the automotive landscape seen in a while — a high-tech inline-six specifically designed to compete with, and outclass, larger motors.

While Mercedes wants to keep you interested with claims of vastly improved economy across platforms, enhanced efficiency is definitely not the most impressive bit of engineering on offer. For example, the aforementioned inline six-cylinder features 48-volt systematic electrification, so there’s no belt drive for ancillary components at the front of the engine. This reduces the overall length of what would normally be a fairly long motor and frees it up for packaging in areas that may have not worked otherwise.

Those 48 volts also work with the engine’s electric turbocharger. Mercedes claims that it only takes the e-turbo 0.3 second to reach 70,000 rpm, followed by the larger twin-scroll exhaust-driven turbo. The intended result is seamless linear power delivery without any turbo lag. The new inline-six is rated by the company to “at least” 408 horsepower and 369 lb-ft of torque and Mercedes says it’ll come in silky smooth with 15 percent better CO2 emissions than the current V6 being offered.

The other spec sheet darling is the slightly lower tech M176 twin-turbo 4.0-liter V8. Although, on paper, this engine looks very similar to the 4.0 biturbo that Mercedes-Benz is already producing, right down to the matching 17 pounds per square inch of boost pressure.

Mercedes says this V8 will output over 476 hp and 516 lb-ft in the upcoming 2017 S-Class with a 10 percent improvement in economy — partly due to cylinder deactivation. However, cylinder shutoff is only active in an engine-speed range of 900 to 3,250 rpm and only when the vehicle operator has selected one of two conservative driving modes. Otherwise, it’s a full-time V8.

In addition to two diesel engines that are somewhat less likely to show up in North America, Benz is also offering a practical 2.0-liter turbo four for next year’s more economic models. The package includes twin-scroll turbochargers that merge the exhaust gas ducts of cylinder pairs into a “flow-optimized” manifold. Mercedes says this setup aids in the production of low-rpm torque. The engine also has a belt-driven 48-volt starter-alternator that is responsible for for fuel-saving hybrid functions such as energy recovery, imperceptible on/off at stops, and boosting the engine-speed range up to 2,500 rpm.

[Images: Mercedes-Benz]

Matt Posky
Matt Posky

A staunch consumer advocate tracking industry trends and regulation. Before joining TTAC, Matt spent a decade working for marketing and research firms based in NYC. Clients included several of the world’s largest automakers, global tire brands, and aftermarket part suppliers. Dissatisfied with the corporate world and resentful of having to wear suits everyday, he pivoted to writing about cars. Since then, that man has become an ardent supporter of the right-to-repair movement, been interviewed on the auto industry by national radio broadcasts, driven more rental cars than anyone ever should, participated in amateur rallying events, and received the requisite minimum training as sanctioned by the SCCA. Handy with a wrench, Matt grew up surrounded by Detroit auto workers and managed to get a pizza delivery job before he was legally eligible. He later found himself driving box trucks through Manhattan, guaranteeing future sympathy for actual truckers. He continues to conduct research pertaining to the automotive sector as an independent contractor and has since moved back to his native Michigan, closer to where the cars are born. A contrarian, Matt claims to prefer understeer — stating that front and all-wheel drive vehicles cater best to his driving style.

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  • Noble713 Noble713 on Nov 01, 2016

    Hopefully Japan will follow Germany's lead, and this will convince Toyota and Nissan to make inline sixes again. I want a successor to the JZ, dammit!

    • Caboose Caboose on Nov 01, 2016

      3.6L I-6 Lexus RC, please, minus 300-400 pounds. -OR- 2.0 I-6 Miata at its current weight. -OR- 4.2L I-6 Lexus LS. -OR- Yay! I love mixing Japanese cars, I-6 lust, and lots of poppies!

  • Carl0s Carl0s on Nov 01, 2016

    It's just a shame Mercedes lag behind with their own gearboxes while everybody else uses ZF or Aisin. 48v will soon be the norm. Another manufacturer was saying it was becoming a necessity.

    • JimZ JimZ on Nov 02, 2016

      I see interior electronics staying 12 volt for a while. 42/48 volt systems have safety implications that 12 volt does not.

  • TCowner We've had a 64.5 Mustang in the family for the past 40 years. It is all original, Rangoon Red coupe with 289 (one of the first instead of the 260), Rally Pac, 4-speed, factory air, every option. Always gets smiles and thumbs ups.
  • ToolGuy This might be a good option for my spouse when it becomes available -- thought about reserving one but the $500 deposit is a little too serious. Oh sorry, that was the Volvo EX30, not the Mustang. Is Volvo part of Ford? Is the Mustang an EV? I'm so confused.
  • Mikey My late wife loved Mustangs ..We alway rented one while travelling . GM blood vetoed me purchasing one . 3 years after retirement bought an 08 rag top, followed by a 15 EB Hard top, In 18 i bought a low low mileage 05 GT rag with a stick.. The car had not been properly stored. That led to rodent issues !! Electrical nightmare. Lots of bucks !! The stick wasn't kind to my aging knees.. The 05 went to a long term dedicated Mustang guy. He loves it .. Today my garage tenant is a sweet 19 Camaro RS rag 6yl Auto. I just might take it out of hibernation this weekend. The Mustang will always hold a place in my heart.. Kudos to Ford for keeping it alive . I refuse to refer to the fake one by that storied name .
  • Ajla On the Mach-E, I still don't like it but my understanding is that it helps allow Ford to continue offering a V8 in the Mustang and F-150. Considering Dodge and Ram jumped off a cliff into 6-cylinder land there's probably some credibility to that story.
  • Ajla If I was Ford I would just troll Stellantis at all times.
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