Mercedes-AMG Admits Paper Performance Doesn't "Resonate" With Buyers
Mercedes-AMG is now admitting what many of us suspected all along: the four-cylinder, plug-in hybrid C63 hasn’t lived up to expectations.
Key Points
- A senior Mercedes-AMG official admitted the 671-hp plug-in hybrid four-cylinder failed to connect with longtime customers and will be phased out.
- The high cost of modifying the M139 engine to meet Euro 7 emissions regulations contributed to AMG’s decision to move away from the current PHEV setup.
- AMG is developing a new flat-plane crank V8 and plans to expand use of its hybridized 3.0L inline-six, signaling a shift back toward larger, more traditional performance engines.
Introduced in 2022 as a radical departure from the traditional V8 formula everyone knew and loved, the M139-based four-cylinder hybrid was promised as the future of AMG performance. But just a few short years on, Mercedes now concedes the experiment may be over.
In a recent interview with Autocar, a senior official at AMG, speaking anonymously, admitted the downsized 2.0-liter powertrain wasn't the right play. “Technically, the four-cylinder is one of the most advanced drivetrains available in a production car. It’s also right up there on performance. But despite this, it failed to resonate with our traditional customers. We’ve recognised that,”
The company is now preparing to replace the M139 PHEV with more conventional options—namely, hybridized inline-sixes and a new flat-plane crankshaft V8 that is still in development.
When Mercedes launched the C63 S E Performance in 2022, it arrived with 671 horsepower from a turbocharged 2.0-liter engine paired with a rear-mounted electric motor and a small 4.8-kWh battery pack. While it technically overpowers the V8 in terms of raw output, the hybrid sedan’s added mass, muted exhaust note, and limited electric range (under 10 miles) dulled enthusiasm. The same powertrain eventually found its way into the GLC63, SL43, and GT43. Performance may be impressive on paper, but buyers and dealers have been tentative.
The powertrain is expected to remain in the lineup for the short term, but it will eventually be phased out, not only due to its lack of appeal, but also because of escalating development costs tied to upcoming Euro 7 emissions standards. AMG would need to invest heavily to bring the M139 powertrain into compliance—an expense the automaker now appears unwilling to shoulder
It's all very ironic. At the time of the C63's hybrid debut, AMG positioned the switch away from V8s as a necessity for emissions compliance. Now, it turns out that reworking the compact four-cylinder to remain in compliance with stricter EU emissions regulations would cost more than it's worth. Make it make sense.
Other models using derivatives of the M139, including the C43 and SL43, are also expected to transition away from the four-cylinder. Engineers are reportedly developing an all-new flat-plane crank V8, but in the interim, the 3.0-liter inline-six used in models like the CLE53 and E53 could be asked to play a greater role.
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An experienced automotive storyteller and accomplished photographer known for engaging and insightful content. Michael also brings a wealth of technical knowledge—he was part of the Ford GT program at Multimatic, oversaw a fleet of Audi TCR race cars, ziptied Lamborghini Super Trofeo cars back together, been over the wall during the Rolex 24, and worked in the intense world of IndyCar.
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Wait, someone paying an extreme premium for a performance car doesn't want the same 4cyl you can find in 35k cars? What a surprise!
As a 3 Mercedes family, I can say get rid of turbos. If I wanted that, I'd be driving a GR Corolla. The 249 HP, normally aspirated 3.5 L V6 in my C300 is perfectly balanced for performance, smoothness, and economy as is the 300 HP 3.5 L V6 in my E-350. How about a normally aspirated, high performance version of the newer inline 6? These are supposed to be luxury cars after all. As for the really well-heeled AMG buyer, I'd suggest a well tuned 7 L V8 that actually sounds and feels powerful, yet still lux. Get back to your roots!