Mercedes-AMG CLE 646 drops all-wheel drive and reaches 200 km/h in 11.4 seconds

646 horsepower is no arbitrary number here

According to official Mercedes-AMG data, the CLE 646 uses a comprehensively further-developed M177 EVO 4.0-litre twin-turbo V8 engine. It produces 475 kW and 850 Nm, with maximum torque available from 2,500 to 4,500 rpm. The 646 in the model name denotes its output in horsepower.

One of the engine’s most important differences is its flat-plane crankshaft. This solution reduces rotating masses, allows the engine to rev more eagerly and makes throttle response more immediate. AMG added three separate cooling circuits, because producing 475 kW is the easy part; repeatedly using that output on a hot race circuit is considerably more difficult.

AMG developed the rear section of the exhaust system with Akrapovič and uses titanium to reduce weight. The 48 V integrated starter-generator adds 17 kW and 205 Nm to the system, but the CLE 646 is not about hybrid tricks. The eight cylinders and petrol still do the main work here.

All-wheel drive was deliberately thrown overboard

One of the foundations of the standard CLE 53 is its AMG Performance 4MATIC+ all-wheel-drive system. AMG removed it completely for the CLE 646. All 850 Nm is sent to the rear wheels through a nine-speed AMG Speedshift TCT 9G automatic transmission.

All-wheel drive would provide better traction from a standstill and probably a more impressive 0–100 km/h time, but AMG preferred lower mass and more direct responses. An electronically controlled locking differential operates at the rear axle, and with ESP switched off, the driver can select between nine traction-control settings.

It reaches 100 km/h in 3.9 seconds. In today’s world of electric super saloons, that figure will not knock anyone out of their seat, but the CLE 646 was not created for traffic-light sprint races. It reaches 200 km/h in 11.4 seconds and has a top speed of 310 km/h.

AMG also publishes its 0–300 km/h time: 36.2 seconds in the Street aero setting and 36.8 seconds in the Track setting. The difference demonstrates the inevitable cost of greater downforce, as additional drag erodes acceleration at high speed.

170 kg lighter, yet still 1,895 kg

AMG removed around 170 kg compared with the donor car. Its kerb weight is nevertheless 1,895 kg, so there is no reason to talk about Lotus territory.

To cut weight, AMG uses carbon fibre for the bonnet, roof, widened wheel arches, side skirts, boot lid, diffuser and adjustable rear wing. The rear side windows and rear screen are made from polycarbonate, while the car receives a lighter 12 V battery. The rear seats have been removed entirely, and AMG has also reduced the sound insulation, audio system and comfort equipment. Even PARKTRONIC stays outside the garage door.

The body received additional reinforcements and an integrated roll cage. Front and rear track widths have increased by 60 mm, while the car sits 22 mm lower at the front and 16 mm lower at the rear. Weight distribution is 56:44 in favour of the front axle.

That is not the ideal balance of a mid-engined supercar, but given the CLE’s origins, it is hardly surprising. AMG’s aim was to make the large-engined front end as precise as possible, not to pretend that the CLE architecture was born as a Le Mans prototype.

KW contributes four-way adjustable suspension

The standard adaptive suspension was not serious enough for the project. Mercedes-AMG and KW automotive developed a steel-spring coilover suspension for the car, with dampers allowing separate adjustment of low- and high-speed compression and rebound.

In practice, this means the body’s movements under braking, acceleration and cornering can be tuned independently of how the suspension reacts to kerbs and sharp bumps.

For braking, the CLE 646 uses 420 x 40 mm carbon-ceramic discs and six-piston calipers at the front. The rear discs measure 360 x 32 mm and use single-piston calipers. AMG also created separate cooling ducts for the brakes.

The tyre sizes also show that this is not a cosmetic AMG package. It wears 305/30 ZR20 tyres at the front and 335/30 ZR20 tyres at the rear. According to AMG, some of their technology comes from the development of the Mercedes-AMG ONE.

More than 250 kg of downforce

The most brutal aspect of the CLE 646 is not even the V8, but its aerodynamics.

At the front, the driver can manually set the diffuser to Street or Race position. In the Race setting, the element extends downwards, accelerates the airflow beneath the car and increases front-axle downforce through the Venturi effect. The centre section of the rear carbon-fibre wing can also be adjusted manually.

Vents in the wheel arches reduce pressure in the wheel wells, channels beside the headlights direct air through the wheel wells, and longitudinal aerodynamic elements operate beneath the floor. At top speed, the package generates more than 250 kg of downforce.

This also explains its rather ugly drag coefficient. Cd is 0.402 in the Street setting and 0.417 in the Track setting. An electric-car engineer would probably get a migraine on seeing figures like these, but the aim here is not to reduce energy consumption. The CLE needs to be pressed into the asphalt at high speed, not slip through the air in a WLTP laboratory.

Mythos takes the Black Series idea and makes it even more exclusive

The CLE 646 is only the second Mythos-series model after the Mercedes-AMG PureSpeed. While 250 examples of the PureSpeed were built, production of the CLE 646 is limited to just 30 cars. AMG hand-builds each car in Affalterbach, and the entire series had already found buyers before its world premiere.

In essence, the CLE 646 fulfils the role that a Black Series model once occupied in the AMG range. The base model remains recognisable, but the engineers transform the engine, chassis, aerodynamics and bodywork so thoroughly that the result is no longer simply a more powerful trim level.

From a European perspective, the timing makes the car especially interesting. Electric sports cars already deliver brutal acceleration figures every day, while AMG itself is moving strongly towards electrification. The CLE 646 answers this not with a larger battery or another electric motor, but with a flat-plane V8, rear-wheel drive and mechanically adjustable suspension.

Its fuel consumption also serves as a reminder of the world in which the CLE 646 exists. The preliminary combined figure is 15.8 l/100 km and CO2 emissions are 359 g/km. Mercedes notes that the values have not yet received official type approval.

For 30 cars that have already been sold, that probably does not matter in the slightest. The CLE 646’s job is not to be rational. Its job is to show what AMG engineers can do when the accountant is sent to another room for a moment.