Mercedes-AMG revives its V8 powerplant with the ultra-limited CLE 646 Special Edition

There’s a new king of Mercedes-AMG super coupes and no, it’s not a Black Series. If only the name were even a tenth as catchy as that. Meet the CLE 646 Special Edition (Spezialanfertigung), which translates as ‘custom-made’. Most importantly, the 646 is Mercedes-AMG’s rediscovery of exactly what its customers expect of it and delivering exactly what everyone’s been crying out for: a CLE coupe with an AMG V8 occupying its engine bay.

Mercedes-AMG CLE 646 engine, power and performance

A development of Mercedes-Benz’s new 4-litre twin-turbo flat-plane-crank M177 Evo unit first seen in a more sedate, 530bhp and 723Nm form in the new Mercedes S-class, serves in the CLE 646. It’s good for 636bhp and 850Nm thanks to some good old AMG fettling. While the flat-plane crank is lighter than before, it also allows the engine to run more cleanly and therefore comply with upcoming and far stricter Euro 7 emission requirements.

An integrated starter generator and a 48-volt electrical system is also incorporated, improving efficiency and contributing up to an additional 23bhp. It all means the CLE 646 should be good to complete the 0-100kmph sprint in 3.9sec and if you hold the loud pedal down for long enough, it’ll top 311kmph.

Mercedes-AMG CLE 646 design and aerodynamics

Feeding and cooling that almighty AMG V8 is a front bumper with more negative space than material. The Panamericana grille has had its bottom jaw removed, extending down into the substantial splitter, with giant ducts for the brake cooling integrated and huge vents alongside for heat exchanger cooling. There’s also a large vent on the bonnet’s leading edge, with two air-guiding elements to feed cooling air to the twin-turbocharger set-up that sits within the V of the engine.

The CLE 646 is 60mm wider than the CLE 53, with bespoke front wings with derigour slashed-out vents to reduce pressure within the front wheel arches. The new sills flow up and into wider rear wheel haunches with the appearance of sitting on top of a production CLE body. Further to the rear is a huge adjustable wing and a new stacked quad exhaust set-up that allows for a wider, deeper diffuser. All told, the 646 is pressed into the ground by 250kg of downforce at its 311kmph top speed.

The CLE 646 is also a sturdy 170kg – let’s call that two passengers – lighter than the CLE 53 thanks to a range of weight-saving measures. Obviously the extensive use of carbonfibre helps, the new wings, bonnet and much of the stripped-out interior being made of the material. The CLE 646 also gets polycarbonate windows. All the same, it’s still a bit of a hefty thing, at 1895kg.

Mercedes-AMG CLE 646 chassis

In terms of its chassis and handling, the CLE 646 ditches the driven front axle of the 4Matic system to be rear-wheel drive only. It features four-way coilovers with high- and low-speed bump and rebound adjustments that have been developed in conjunction with KW Automotive. A consequence of its new chassis hardware is a 16mm drop in rear ride height and 22mm at the front. It is also fitted with AMG’s sophisticated nine-stage traction control system to allow the driver to precisely dial the car in for their skill level. Sending the V8’s performance to the rear axle is Mercedes-AMG’s 9-speed TCT transmission, while it’s distributed between the wheels by an electronically controlled limited-slip diff.

The new hollowed-out forged 20-inch wheels are fitted with Michelin Pilot Sport Cup 2 R tyres, measuring 305-section at the front and a massive 335-section at the rear – only just shy of the rears on a Lamborghini Revuelto. Those wheels and tyres shroud ceramic brakes, with 420mm discs at the front clamped by six-piston callipers. The rears are 360mm with a single-piston floating calliper.

Mercedes-AMG CLE 646 interior

As above, the CLE 646’s interior features weight-saving carbonfibre and gets new bucket seats with six-point harnesses. It’s also a strict two-seater, with a substantial roll cage and harness bar where the rear seats are in a CLE 53. Save for the seats, cage, carbon and alcantara however, the interior is recognisable CLE, with a driver’s display and central vertical tablet and five-vent climate set-up.

Mercedes-AMG CLE 646 price and availability

There will only be 30 CLE 646 Special Editions (Spezialanfertigungs) made, all sold and making it Mercedes-AMG’s rarest model to date and very much in keeping with the ‘Mythos’ family it joins, following the 250-off PureSpeed Roadster. It’s even rarer than the 75-off McLaren-Mercedes SLR Stirling Moss.

However, while all the CLE 63s have been sold at an undisclosed price this won’t be the only outing for AMG’s new hot-vee V8. The work that has gone into the creation of the CLE 646 will inform the forthcoming Mercedes-AMG CLE 63 coupe. Yes, it’s now all but confirmed that the V8 will be returning to a flagship coupe rival to BMW’s M4, that will be available for all to order. Just don’t expect the full 636bhp output.