New Mercedes Super-sportscars in Compact Class

August 4, 2019

The new Mercedes-AMG compact A 45 4MATIC+/ A 45 S 4MATIC+ sports cars reassert their leading positions in their segments. They seamlessly continue the success story of their predecessors, while setting numerous new standards, according to a statement by the automaker. Available in two output and torque variants, the completely newly developed 2.0-litre engine is the world’s most powerful turbocharged four-cylinder engine in manufactured for series production. Even the basic model with 285 kW (387 hp) is more powerful than its predecessor. The S-variant with 310 kW (421 hp) jostles with considerably higher vehicle classes. Perfect sequences in all driving situations, and fast gearshifts measured in milliseconds, are guaranteed by the new AMG SPEEDSHIFT DCT-8G dual-clutch transmission with eight gears. The active, fully-variable AMG Performance 4MATIC+ all-wheel drive distributes the power to the rear axle wheel-selectively by AMG Torque Control – for top traction and the spectacular Drift mode. This is made possible by a new rear axle differential featuring two multidisc clutches – one for each rear wheel.

With its new compact sports models Mercedes-AMG is demonstrating its high competence in development once again: “We have completely redesigned our “45” models – from the engine and transmission through the chassis, the elaborately constructed drivetrain to the body structure and of course the design itself – all with one goal: to raise vehicle dynamics and the sporty driving experience to a level previously unimaginable in the compact class. With the presentation of this, our most powerful and most dynamic compact sports car, we are also reinforcing the significance of this segment for our growth strategy”, says Tobias Moers, Chairman of the Management Board of Mercedes-AMG GmbH.

Exterior design: AMG family membership even more apparent

The new Mercedes-AMG A 45 4MATIC+ and CLA 45 4MATIC+ models are even more distinctive than their predecessors. The exterior conveys sheer driving pleasure even at standstill. For the first time, the compact class now also features the AMG-specific radiator grille with a wider lower contour and twelve vertical louvres – as a clear indicator of AMG Performance family membership. At the same time, the pronounced “shark nose”, the slim, deeply contoured headlamps and the flat, aerodynamically favourable bonnet with powerdomes visually lower the front section to create the impression of extremely dynamic forward thrust.

The imposing presence is also accentuated by the wider front wings with flared wheel arches. These create space for the wider front axle, and underline the athletic appearance. This muscular impression is even stronger with the A 45 4MATIC+ than with the CLA 45 4MATIC+, as the basic CLA already has a wider front track and the wings could be flared to a lesser extent.

Individual details as distinguishing features

The front apron is also a distinguishing feature. In the A 45 4MATIC+ it is in a jet-wing design. Horizontal fins in the outer air inlets and the stretched lower air inlet emphasise the impression of width. The

CLA 45 4MATIC+ has an even more expressive appearance with its jet-like external air inlets, showing its close family relationship with the AMG GT 4-door Coupé. The front splitter transitions seamlessly into the side air curtains ahead of the front wheels, which optimise the airflow to improve aero-performance and the Cd figure.

Viewed from the side, the wider AMG side skirts visually lower these compact sportscars so that they appear to hug the road more closely. If the Silver Chrome package is specified, the inserts are in silver chrome, and with the AMG Night package they are in high-gloss black.

The exterior mirrors are mounted on the door muscle, echoing the look of Mercedes-AMG coupés and sportscars. This not only looks very sporty, but also improves the aerodynamics.

As standard the basic variants feature 8.5 J x 18-inch light alloy wheels in a 10-spoke design, aerodynamically optimised and painted in tantalum grey with size 245/40 R 18 tyres.

The S-models are equipped with 19-inch light alloy wheels in a 5-twin-spoke design ‑ with a width of 8.5 inches for the A 45 S 4MATIC+ and nine inches for the CLA 45 S 4MATIC+. The attractive aluminium rims are aerodynamically optimised and painted in tantalum grey with a high-sheen finish, and shod with tyres in size 245/35 R 19 and 255/35 R 19 (CLA 45) respectively. In the basic models the AMG high-performance braking system features grey-painted brake callipers with white AMG lettering. The S-versions are recognisable by their larger, red-painted 6-piston brake callipers with black AMG lettering.

Round twin exhaust tailpipes for the Performance compact cars

The rear view is characterised by two round twin tailpipes (82 mm diameter) and the wide rear apron. The S-models are distinguished by their larger, 90 mm exhaust tailpipes with internal fluting and AMG lettering. The impression of width at the rear is emphasised further by the slim two-piece rear light clusters. The diffuser with two vertical twin fins contributes to better aero-performance (CLA 45: four individual fins) – it is extended forward at the centre of the vehicle, making it work more effectively. The effect is rounded off by the spoiler lip in the vehicle colour on the roof spoiler, or on the boot lid (CLA 45).

The most important optional exterior features:

AMG Aerodynamic package for optimised aerodynamic balance, included a modified front splitter and additional flics on the front apron, an additional diffuser blade, side spoiler lips on the rear apron and rear spoiler (A 45) or larger spoiler lip (CLA 45) in high-gloss black. These features increase the downforce, and therefore handling stability at the physical limits

19-inch light-alloy wheels in a 5-twin-spoke design, aerodynamically optimised, painted either in tantalum grey with a high-sheen finish or in matt black with high-sheen rim flange

19-inch forged wheels in a cross-spoke design, painted either in titanium grey with high-sheen finish or in matt black with high-sheen rim flange, with simulated central wheel lock in aluminium

AMG Night package with design features in high-gloss black ‑ for example the front splitter or inserts in the sideskirts ‑ and black chromed exhaust tailpipes

Silver Chrome package with front splitter and inserts in the sideskirts in silver chrome

Bodyshell: extensively reinforced

The AMG developers extensively reinforced the bodyshell, as it provides the basis for the precise self-steering characteristics, as well as track and camber stability, also when driving at high speed. A lightweight aluminium plate bolted underneath the engine – the “shearing plate” – increases the torsional rigidity at the vehicle’s front end. This is supplemented by a strut tower brace between the front suspension struts and pistol-shhaped “shotguns” ‑ these are additional reinforcing plates connecting the side members to the A-pillars to minimise movements of the front section. Diagonal struts at the front and rear of the underbody further improve rigidity. As a result the entire suspension system responds highly precisely even at the physical limits, giving the driver clearly defined feedback – with considerably reduced body torsion around the longitudinal and transverse axis, and less rolling and pitching on bends, when braking and during load cycles.

Drive system: new turbocharged four-cylinder with ample power

With an output of up to 310 kW (421 hp), the completely newly developed 2.0-litre engine is the world’s most powerful turbocharged four-cylinder manufactured for series production. Mercedes-AMG has bettered the output of the preceding engine by 30 kW(40 hp). Maximum torque has also increased from 475 to up to 500 newton metres. With an output per litre of up to 155 kW (211 hp), the new Mercedes-AMG high-performance turbo engine even ranks ahead of many well-known super-sports car engines. The new, highly efficient powerpack is produced on an innovative production line in Affalterbach, on the “One Man, One Engine” principle.

In the 45 models, the four-cylinder ensures extremely agile performance in two output classes: with 310 kW (421 hp) as the S-model and with 285 kW (387 hp) in the basic version.

This positioning logic has already proved successful for the AMG Performance models with a V8 engine, and meets individual customer wishes even better. The new compact sportscars absolve the sprint from zero to 100 km/h in record time: the A 45 S 4MATIC+ requires only 3.9 seconds (CLA 45 S 4MATIC+: 4.0 seconds), while the basic A 45 4MATIC+ model absolves this discipline in 4.0 seconds (CLA 45 4 MATIC+ in 4.1 seconds). The top speed of the basic models is electronically limited to 250 km/h, while the S-models are capable of up to 270 km/h ex factory. With the optional AMG Driver‘s Package, the top speed can also be increased to 270 km/h for the basic variants.

Apart from its performance figures, the new engine impresses with its immediate response. To this end the torque curve was carefully balanced (“torque shaping”): The maximum torque of 500 Nm (480 Nm in the basic variants) is available within a range of 5000-5250 rpm (4750-5000 rpm in the basic variants). With this configuration the AMG engineers have achieved a power delivery akin to a naturally aspirated engine. The engine developers were able to realise a dynamically increasing torque curve in the lower engine speed range, thereby improving throttle response. The increasing torque at higher rpm makes the engine more free-revving. Moreover, the high maximum engine speed (up to 7200 rpm) emphasises the engine’s sporty character.

Engine design: intelligent details

The new engine excels with numerous intelligent design features. Unlike the likewise transversely installed four-cylinder in the 35 models or the preceding model, the new engine is rotated around its vertical axis by 180 degrees. This means that the turbocharger and the exhaust manifold are now positioned at the rear, on the side of the firewall when viewed from behind. The intake system is therefore positioned at the front. This configuration allows the flattest possible and aerodynamically advantageous front section design. Furthermore, the new arrangement allows much improved air ducting with shorter distances and fewer diversions – both on the intake and exhaust side.

Turbocharger: roller bearings reduce mechanical friction

The new twinscroll turbocharger combines optimum responsiveness at low engine speeds with a high power in the upper rpm range. In addition to this, the turbine housing is divided into two flow passages which run parallel to one another.

Together with the likewise divided ducts in the exhaust manifold, this makes it possible to feed the exhaust flow to the turbine separately. The aim is to prevent the individual cylinders from influencing each other negatively during load cycles, and to improve the gas cycle. The result is higher torque at lower engine speeds, and extremely good responsiveness.

Furthermore, the shafts of the compressor and turbine have roller bearings for the first time ‑ as in the top output variant of the AMG 4.0-litre V8 engine in the AMG GT 4-door Coupé. The roller bearings reduce mechanical friction within the turbocharger to a minimum. The charger therefore responds more readily and reaches its maximum speed of up to 169,000 rpm more rapidly.

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