The word is out, and the fanboys aren’t happy. The new Mercedes-AMG C63 won’t have a V8 under the bonnet.

It gets worse. The successor to AMG’s autobahn-storming, BMW M3-bashing sedan is in fact a plug-in hybrid with a four-cylinder engine. That sound you hear is C63 aficionados sobbing into their beers.

But AMG chief technical officer Jochen Hermann is unrepentant.

“We could have just done another V8 C63,” he says. “But we would have been stuck in the past.”

And you only need to take a close look under the skin to see the Mercedes-AMG C63 S E Performance is very much a muscle car of the future. 

Yes, it’s a plug-in hybrid built around a four-cylinder internal-combustion engine, but that’s where the similarities with, say, a Mitsubishi Outlander end.

Many of the new C63’s key technologies and operating principles are derived from a 1.6-litre hybrid that is the most advanced and highest-performing powertrain ever to carry the three-pointed star – the EQ10 Power+ powertrain used in the Mercedes-AMG Petronas Formula 1 racers.

This hybrid is all about performance, not fuel economy.

The headline numbers are impressive: 500kW and 1020Nm, 0-100km/h in 3.4 seconds, and a top speed of 280km/h with the optional AMG Driver’s Package fitted (250km/h otherwise). It’s the most powerful C63 ever, quicker than the 4.0-litre twin-turbo V8 car it replaces, and the 6.2-litre naturally-aspirated V8 model before that.

What’s more impressive than the numbers, however, is how they’re produced.

The C63’s hybrid powertrain consists of a 350kW version of AMG’s M139l inline four and a 150kW e-motor mounted at the rear axle, both supported by a robust 400V electrical architecture.

The M139l four-banger under the bonnet drives all four wheels through AMG’s proven Speedshift multi-clutch nine-speed automated transmission.

As in the C43 and SL43, the engine features a 48V electric turbocharger that delivers faster response, but in the C63 the turbocharger is larger and powered by the 400V system. Also integrated into the 400V system is the belt-driven starter-alternator.

The e-motor drives the rear wheels through its own automated two-speed transmission, which shifts to high gear at 140km/h, and an integrated electronically controlled limited-slip differential.

It also sends drive forward via a separate propellor shaft to a clutch unit at the rear of the nine-speed transmission, from which it can be distributed to the front wheels when needed.

AMG development engineer Peter Szalay says this setup avoids having to put the e-motor’s torque through the AMG Speedshift transmission, which is limited to about 1000Nm, and allows it to freely distribute torque to the front and rear axles as needed. 

More importantly, says Szalay, had the ICE and the e-motor shared the same output shaft, the system could not deliver maximum power because the power peaks of both occur at different revs.

“We didn’t put the e-motor ‘on top’ of the internal combustion engine,” he explains. “Instead, we have a ‘virtual’ engine that provides the output demanded by the driver in the fastest, most responsive way, using the best characteristics of both.”

Key to making the C63’s powertrain work is the AMG-developed 400V electrical architecture and high-performance 6.1kWh battery, which is mounted at the rear of the car.

Though the compact 89kg battery can be recharged via a plug and will deliver an EV driving range of 13km at speeds up to 125km/h, that’s not what it’s primarily designed to do. 

Instead, it’s designed to deliver rapid bursts of energy when required by the e-motor – a kickdown function ensures the full 150kW of the e-motor is available on demand in any of the C63’s eight drive modes.

It also ensures it’s able to be replenished rapidly – either by the engine, or via recuperation rates of more than 120kW under heavy braking/in the highest of the four available regen settings. 

To survive that sort of punishment the battery has a cooling system that circulates a high-tech coolant directly around each of its 580 cells to ensure it’s always at the optimal temperate to deliver maximum performance.

This C63 is the first with all-wheel drive, and not just to help the chassis cope with the hybrid powertrain’s hefty power flows.

“Our customers were asking for it,” says Peter Szagay. “It was the next logical step.”

Installing the e-motor, battery pack, and associated hardware at the back axle has delivered a 50/50 front to rear weight distribution. Standard suspension is by way of steel springs with AMG’s adaptive shocks. There are three different damping maps – Comfort, Sport, and Sport+. 

Standard also is rear-wheel steering – though as this is an AMG, the operating parameters are different from those on the regular C-Class. At speeds up to 100km/h, the rear wheels will steer up to 2.5 degrees in the opposite direction to the fronts to improve turn-in response.

Over that speed, the wheels will steer up to 0.7 degrees in the same direction as the fronts to help with high-speed stability.

Standard wheels are 19-inch units with 20s available as an option. The tyre setup is staggered – on the 20-inch-wheel equipped cars we saw, the fronts were 265/35 and the rears 275/35.

Visually, the new C63 wears familiar AMG styling traits, from the grille’s menacingly toothy grimace to the large calibre quad exhaust peeking out from under the rear bumper. But there’s function behind the form.

The front track is 76mm wider than that of the standard C-Class, and the wheelbase has increased 10mm. That, and the need to package additional heavy-duty cooling systems at the front of the car, mean the new C63 is also 50mm longer from the base of the A-pillar to the leading edge of the front bumper, and 83mm longer.

The entire front clip is thus unique to the C63, with the bonnet featuring a rear-facing vent that’s a nod to giant opening on the AMG GT3 race cars. Unlike the GT3 vents, which are used to help generate front axle downforce, the C63’s much smaller opening is purely used to free hot air from the engine bay.

AMG fans will find the interior ambience very familiar, with Alcantara and contrast stitching, carbon fibre trim, and splashes of contrast colour used throughout. New performance front seats are 2kg lighter than those of the outgoing model, and the dial under the left spoke of the AMG performance steering wheel can be used to change regen modes.

Both sedan and wagon versions of the new C63 will be available in Europe when the car goes on sale early next year.

Though the higher load space floor is more noticeable in the back of the wagon than in the boot of the sedan, AMG engineers have done a brilliant job of packaging the e-motor and battery at the rear of the car. Both are still usable, everyday vehicles.

Of course, what you all want to know is this: What does this four-cylinder plug-in hybrid C63 go like? And what sort of noise does it make? Does it deliver the sound and fury we so loved about the previous C63s?

We’ve been hurled around the challenging race circuit at Mercedes-Benz’s proving ground in Immendingen in southern Germany in a lightly camo’d pre-production car, with AMG’s Jochen Hermann at the wheel, so we have some answers.

But we’re not allowed to tell you until next month. Stay tuned.

MORE: Everything Mercedes-AMG C63

Angus MacKenzie
Angus MacKenzie is a International Contributor at CarExpert.
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