Mercedes-AMG CLE 646 Spezialanfertigung: 646 hp, RWD V8

Mercedes-AMG has revealed the CLE 646 Spezialanfertigung, a strictly limited, hand-built coupé from its Mythos series. The car drops the CLE’s all-wheel-drive system for pure rear-wheel drive, adds a 646 hp (475 kW) V8 biturbo and sheds around 170 kg (375 lb) through carbon bodywork and a widened, reinforced shell. AMG says the project began as an engineering team’s own idea rather than a planned product, and the result is aimed squarely at winding roads and closed circuits.

Mercedes-AMG has used its Affalterbach headquarters to build what it describes as a complete rework of the CLE Coupé rather than a conventional special edition. The company says the starting point was a single question inside the development team — how far could a CLE be pushed towards maximum driving dynamics — and that a small group began by building a prototype before the car was signed off as a limited Mythos model.

A 4.0-litre V8 with a flat-plane crank

The centrepiece is a heavily reworked version of AMG’s M177 EVO 4.0-litre V8 biturbo, rated at 646 hp (475 kW) — the number that gives the car its name. Peak torque is 850 Nm (627 lb-ft), available across a broad band from 2,500 to 4,500 rpm. AMG uses a flat-plane crankshaft here to cut rotating mass, which the company says improves the engine’s willingness to rev and sharpens throttle response, supported by revised mapping.

The V8 runs three cooling circuits — a high-temperature circuit for the engine, plus low-temperature circuits for charge air and transmission oil and for the 48V components. All have been strengthened for track use and high ambient temperatures, according to the manufacturer. The high-flow exhaust system uses titanium to save weight, and its cold-end design was developed together with Akrapovič.

From 4MATIC+ to rear-wheel drive

The most fundamental change sits in the driveline. The standard car’s AMG Performance 4MATIC+ all-wheel-drive system has been deleted entirely, so the CLE 646 sends all of its drive to the rear axle. AMG says the switch saves weight and changes the car’s character, with an electronically controlled limited-slip rear differential varying the locking effect to balance traction and stability — and, in the right conditions, to allow controlled drifts.

The nine-speed AMG SPEEDSHIFT TCT 9G automatic carries over, with shift behaviour adjustable through AMG DYNAMIC SELECT, and launch control has been recalibrated for rear-wheel drive. AMG quotes 11.4 seconds from rest to 200 km/h (124 mph) and a top speed of 310 km/h (193 mph). No 0–100 km/h figure is given.

Coilovers, ceramics and a wider track

Suspension is a steel coilover set-up developed with KW automotive, using four-way damper technology with independently adjustable low- and high-speed compression and rebound. The body sits 22 mm lower at the front and 16 mm lower at the rear.

The track grows by 60 mm at both axles, which required the bodyshell itself to be widened and reinforced. That makes room for forged AMG wheels measuring 11.0J x 20 at the front and 12.0J x 20 at the rear, wearing 305/30 ZR 20 and 335/30 ZR 20 tyres that AMG says are based on developed technology from the Mercedes-AMG ONE.

Braking is handled by AMG’s ceramic composite system: internally ventilated and drilled 420 x 40 mm discs with six-piston fixed callipers up front, and 360 x 32 mm discs with single-piston floating callipers at the rear, all behind gold-painted callipers. A dedicated cooling set-up feeds them through large front-bumper inlets and air-guiding elements in the axle.

Carbon almost everywhere

The widebody shell leans heavily on carbon fibre: the flared wings with integrated louvres, the front apron, the side member covers, the bonnet with its central cold-air intake, the roof, the rear apron with diffuser, the stiffened boot lid and the manually adjustable rear wing on twin trapezoidal supports. The rear side windows and rear screen are polycarbonate, and even the 12-volt starter battery is a lighter item. Together with the changes to the body-in-white — which also gains extra reinforcement and an integrated roll bar — the car is around 170 kg (375 lb) lighter than the model it is based on.

The front section is finished in Mojave Silver magno, with the body from the B-pillar back in Obsidian Black magno, and AMG crests sit on both doors.

Aerodynamics with a track setting

Front diffuser, wing louvres, underbody measures and rear wing are described as one coordinated system. The front diffuser can be manually set to two positions using three adjusting screws — “Street” and “Race”, the latter intended for circuit use only. Extended downwards, it forms an inverted wing profile that accelerates airflow under the nose and generates a Venturi effect, increasing front-axle downforce. The centre section of the carbon rear wing can then be adjusted to restore aero balance at the rear.

“The Mercedes-AMG CLE 646 Spezialanfertigung is the epitome of AMG for me. The vehicle came about because rational engineers dreamed of a very irrational vehicle. We made that dream come true – in the form of maximum driving dynamics and an incomparable driving experience.”

That is Dr. Stefan Weckbach, Chairman of the Board of Management of Mercedes-AMG GmbH and Head of the Mercedes-Benz G-Class and Mercedes-Maybach business units. Chief Design Officer Bastian Baudy adds that the extensive use of carbon allowed “a particularly striking design language that would otherwise be hardly possible”, and describes the car as “a statement full of performance and character”.

What it means

Stripping out all-wheel drive, fitting manually adjustable aero and building the car by hand in Affalterbach places the CLE 646 in the same rarefied territory as limited-run track-focused coupés from Porsche and BMW’s M division, rather than alongside the regular CLE 53 and CLE 63 line-up. It also signals that AMG intends to keep the combustion V8 at the centre of its halo models: WLTP figures are quoted at 15.8 l/100 km combined and 359 g/km of CO₂, in efficiency class G.

Facts: Mercedes-AMG CLE 646 Spezialanfertigung

Engine: AMG 4.0-litre V8 biturbo (M177 EVO), flat-plane crankshaft
Power: 646 hp (475 kW)
Torque: 850 Nm (627 lb-ft) at 2,500–4,500 rpm
Drive: rear-wheel drive, electronically controlled limited-slip differential
Transmission: AMG SPEEDSHIFT TCT 9G
0–200 km/h: 11.4 seconds
Top speed: 310 km/h (193 mph)
Weight saving: approx. 170 kg (375 lb) versus the base model
Track: +60 mm front and rear; ride height −22 mm front, −16 mm rear
Wheels/tyres: 11.0J x 20 with 305/30 ZR 20 front; 12.0J x 20 with 335/30 ZR 20 rear
Brakes: ceramic composite, 420 x 40 mm front / 360 x 32 mm rear
Consumption (WLTP): 15.8 l/100 km combined, 359 g/km CO₂, class G