Mercedes-Benz announced its first gas-powered inline-six in ages in 2016, and now, AMG's got its hands on it. At the Detroit Auto Show, both the Mercedes-AMG CLS53 and E53 Coupe and Cabriolet made their debut. These are the first straight-six powered AMG cars in years, and the brand's first ever hybrid production models.
The story with the so-called "53-series" is really about the powertrain. AMG's inline-six is based on the regular Mercedes M256 3.0-liter unit that's in the CLS450, but it makes 429 hp and 384 lb-ft of torque in the 53-series.
But where things get really interesting is with the CLS53 and E53's 48-volt hybrid system. These engines replace the traditional belt-driven starter and alternator with an electric motor, called EQ Boost, that sits between the engine and transmission. This starter-alternator regulates the gas engine's idle speed, recuperates energy, and in brief scenarios, provides an extra 21 hp and 184 lb-ft of torque. And because this starter-alternator allows Mercedes to do away with belts, it means this straight-six is smaller than a traditional unit.
This straight-six uses a traditional exhaust-driven turbocharger, but the 48-volt system also spins up an electric turbocharger. Mercedes isn't calling this a twin-turbo engine, as such, but you can think of these turbos as functioning similarly to a typical twin sequential setup. The smaller electric turbo spins up almost instantly, providing nearly lag-free low end power, while the bigger exhaust-driven turbo works higher in the rev range.
In both the CLS53 and E53, this engine is hooked up to the same nine-speed automatic used in the new E63 that replaces the traditional torque converter with a wet startup clutch. You also get AMG's new 4matic+ all-wheel drive system that offers fully variable torque distribution between the front and rear axle. These cars are also equipped with AMG-tuned air suspension system that promises better handling than their standard counterparts.
Performance should be good too. Mercedes quotes a 4.3-second sprint to 60 mph for the E53 Coupe while the CLS53 and E53 Cabriolet take 4.4 and 4.5 seconds to do the same, respectively. All three are electronically limited to 130 mph.
And just as you'd expect, you get all the luxury and safety tech Mercedes has to offer in the 53-series. Their interiors look pretty snazzy too, but we'd probably skip the carbon fiber trim.
Pricing will be announced at a later date, but we do know that the 53-series should go on sale later this year. AMG says that this is its first step into more hybrid offerings, and to us, it sounds like a damn interesting step. Watch this space for more, as we're talking with AMG boss Tobias Moers later today.