AMG’s new engine is its own hydro plant
Straight-six turbo hybrid built for electrification
The 2019 Mercedes E 53 AMG Coupe is one of the latest in a wide and growing range of high-performing posh rockets from the in-house, go-fast department at Mercedes-Benz.
As AMG products do, the E 53 adds numerous high-performance touches to an otherwise far tamer machine, balances everything tidily off of everything else, and turns in a driving experience where you can lounge leisurely down the highway in peace and quiet, or, blast exotic sound effects from the tailpipes while experiencing face-peeling acceleration, all from the lap of luxury.
My tester was, in simple terms, a big, fast, beautiful and comfy coupe — complete with a knockout cabin that’ll wow occupants for years to come.
And the body? Perhaps the polar opposite of most with which it competes: instead of angular and jagged, the E 53 is nothing but curvaceous and graceful. There aren’t a lot of luxury cars with this sort of polished-pebble smoothness to the bodywork, and I love how different it looks.
Expensive, too. Starting price on this touring-ready hot-rod begins in the mid-80s, and optional add-ons to my tester pushed the sticker up into low six-figure territory.
That’s not an asking price within reach of the masses, but as it often goes in cars like this, new technologies are debuted that will, before long, likely wind up in a driveway near you.
Case in point, and I figure, the big story on this machine? The latest AMG powerplant. The engineers call it the M 256. You and I call it a turbocharged straight-six, with 429 horsepower and 384 lb.-ft. of torque.
Beyond the giggle-worthy output figures though, this engine offers up another unique characteristic: It was engineered to be a fully-integrated, highperformance hybrid engine, and one with a few cutting-edge tricks up its sleeve.
Key among them? A single motor-unit housed between the engine and transmission does triple-duty as the E 53’s starter, alternator, and supplemental electric motor. This important assembly is called the Integrated Starter Generator, or ISG. It’s part of the E 53 AMG’s EQ Boost system.
When the driver presses the ignition switch, the ISG starts the engine by spinning it, without the need for a conventional starter. So it starts like a hybrid with no starter noise, and instead, just a gentle hum into action, followed by the throbbing snarl at idle from the tailpipes.
The ISG also generates its own electricity, negating the need for an alternator. This is why the engine has no beltdriven accessories. And, without belt-driven accessories, the engine is shorter in length, helping make it possible to fit a straight-six under the hood, in place of a compact and more conventional V6 setup.
So, with the ISG on board, this turbocharged straight-six engine is also its own hydro station. As you simply drive around, it makes piles of its own electricity, which runs on-board accessories, and also, fills the battery that powers the new 48-volt hybrid system.
The self-generated power stored in that hybrid battery can be used later, to power the ISG’s electric motor function. This provides drivers with an additional 29 electrically-generated horsepower, using no extra gasoline. It’s like an electric boost.
And speaking of electric boost, there’s even a device called the electric auxiliary compressor. Capitalizing on the abundance of electricity generated by the ISG, this small electric turbocharger creates lowRPM boost, even before you press the throttle. Put another way, it pressurizes the engine’s intake tract, before the big exhaust-driven turbocharger is able to. This solves the age-old inconvenience of turbo-lag entirely, with a small electric compressor that can go from zero to hundreds of thousands of RPM in milliseconds.
From the driver’s seat? From the first touch of throttle, you’ve got electric turbo boost, and electric motor boost, ready to get you up to speed in a jiff. That’s in addition to the motive power of the straight-six engine itself, and the big conventional turbocharger bolted to the side of it. So, just breathe on that throttle, and off you go, in a hurry. All of this as the big turbocharger spools fully into action a moment later, emitting a delightful hiss, and letting drivers say sayonara to wherever they were a moment ago.
From the driver’s seat? This all translates into liquid-smooth, immediate, and almost alarming throttle response, with no let-up until the throttle is released. Get AMG’s speedshift transmission cooking in sport+ mode, and upshifts come fast and loud, with each severed from the next like a meat-cleaver through an uncooked hot-dog. Wham! Second. Wham! Third.
You won’t believe how fast or precisely this shifts, and you laugh a little because it’s joyously quick and almost strangely smooth about the whole process of accelerating at nearly-hilarious speeds. The sound? A distinctive straight-six howl, with plenty of exhaust snort, but a good bit of mechanical music, too.
Several passengers said the sound reminded them of the sound of the old Toyota Supra.
But unlike the straight-six in that decades-old Japanese supercar, the latest from AMG has absolutely zero turbocharger lag. Throttle response is, at times, on par with a sporty electric car — punchy and smooth and quiet and impossibly immediate. For the luxury performance car driver, that’s a good thing.
So is the fuel mileage, potentially. Economy figures suggest the E 53 is a few ticks better on fuel than something with comparable firepower, and mostly, I figure the hybrid system here will be more a performance enhancement than a gas-saver, since AMG drivers typically like to hustle.
Simply, this engine has as many systems designed to combust more fuel for power as it does systems to save fuel by creating and deploying its own electricity in crafty ways. It can, for instance, briefly shut the engine off to save fuel while you’re freewheeling on the highway, or, as you’re braking for a stop.
It’s an interesting set of tools for the driver to use and they all help you use less fuel more of the time, while making this a better luxury performance experience. And all of this technology will wind up in a sort of gene pool, that future products will draw from.
So, use the new high-performance hybrid tech for thrills, or, reduced fuel bills. It’s all up to your right foot.