Mercedes-AMG is preparing to phase out the controversial four-cylinder plug-in hybrid drivetrain from the C63 and GLC 63, marking a strategic shift in the brand’s engine line-up.
Speaking to Autocar at the unveiling of the Concept GT XX in Germany, a senior insider confirmed that future petrol-powered Mercedes-AMG models are set to adopt either an updated version of today’s in-line six-cylinder engine or an all-new V8 featuring a flat-plane crankshaft, similar in design to that used by the GT Black Series.
“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,” said the source.
The 2.0-litre M139-based four-cylinder, paired with an electric motor for a combined system output of over 670bhp in the C63 S E Performance, was introduced in 2022 to much fanfare but drew criticism from enthusiasts for its lack of character and weight compared with its V8-powered predecessor.
While a precise timeframe for the phase-out has not been confirmed, Autocar has been told the engine will remain in production for the time being before “eventually” being replaced.
Among the key reasons for the shift in strategy is the high cost of engineering the four-cylinder to comply with upcoming Euro 7 emissions regulations.
“There’s no doubt about its potential – this is one of the most sophisticated engines we’ve ever built – but the investment to make it EU7-compliant is very high,” said the source.
The move comes as Mercedes-Benz prepares to discontinue a number of compact models that used the M139 engine, including the A-Class hatchback. It also signals a rethink for models such as the SL 43 4Matic, which is expected to adopt a new turbocharged six-cylinder engine to replace its current 375bhp 2.0-litre unit.
Speaking to journalists at the same event, Mercedes-Benz CTO Markus Schäfer reaffirmed AMG’s commitment to a dual-drivetrain strategy.
“AMG will continue with a dual strategy – two pillars. The electric pillar will grow significantly. But the second pillar – hybridised internal-combustion engines – will also remain,” he said.
“AMG and Mercedes are working together on a brand-new V8 engine. That engine will support upcoming emissions regulations. There will still be six- and eight-cylinder units, all electrified with either 48V systems or full hybrid set-ups.”
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there's a surprise...
people spending £100k on a car dont want a 4 cylinder engine..
I can't believe they were so surprized the tax dodging PHEV engine was such a flop.
Everyone including AMG new it was risky but you can't hit CO2 Fleet averages/ZEV mandate CO2 targets by selling higher volume V8s like the C63 so they didnt have much of a choice.
Obviously did have a choice as they're reversing their decision and going back to a V8 or inline 6.
By everyone you don't see Porsche dropping a 4 pot into the 911, or Audi dumping the straight 5 in the RS3 or V8 in the RS6.
It was Mercedes penny pinching and they got caught.
they arent reversing the decision though. They havent said there will be a C-Class V8. They have said there will be an inline 6 so we probably get a C53 and no C63 at all because a) there is no room for an electrified V8 in there b) a non-electrified one would be circa 300g/km and the probably of fleet CO2. The flat plane crank goes in the same cars that were keeping V8s anyway like G, GT(ie in the same way a 911 doesnt get a 4 pot there is still a V8 in the GT) etc
I notice that you were quick to pick VW group here side stepping the obvious the fact that BMW faced the same hard choice and went with a massively heavy BMW M5 Hybrid compromised in order to hit 35g/km of CO2. The problem with choosing VW is their strategy was the one someone with an engineering reputation like Mercedes can't take which is simply to fail like VW did and be forced to take multiple fines of 100s of millions of euros for missing their average CO2.
Weird you would suggest penny pinching because the development cost of that ultra-complex F1 derived hybrid would have been astronomical compared to just slamming their existing V8 in there.
Real world fuel economy would likely be double what you get in the PHEV C63 once the engine is doing all the heavy lifting. Most PHEVs are never recharged, and even when they are, they only provide a very short distance where the car can operate in EV-only mode. More often than not the extra weight penalty makes the car much less efficient overall than if it was just a traditional hybrid like a Prius.