2020 Mercedes-Benz CLA45 S AMG 4Matic Shooting Brake UK

New four-cylinder turbo engine delivering superlative power

With an output of up to 310 kW (421 hp), the completely new Mercedes-AMG 2.0-litre engine is currently 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. The new, highly efficient powerpack is produced on an innovative production line in Affalterbach, on the “One Man, One Engine” principle.

The four-cylinder engine delivers extremely agile drive power in two output ratings: with 310 kW (421 hp) as the S-Model and with 285 kW (387 hp) in the basic version. The new compact sportscars absolve the sprint from zero to 62 mph in record time: the CLA45 S 4MATIC+ Shooting Brake requires just 4.0 seconds, while the base model CLA45 4MATIC+ Shooting Brake gets up to speed in 4.1 seconds. The top speed of the base model is electronically limited to 250 km/h (155 mph), while the S-Model leaves the factory with a top speed of 270 km/h (167 mph). With the optional AMG Driver’s package, the base variant can also driven at up to 270 km/h (167 mph).

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 peak torque of 500 newton metres (480 newton metres for the basic version) is available in a range of 5000-5250 rpm (4750-5000 rpm in the basic version). With this configuration the AMG engineers have achieved a power delivery akin to a naturally aspirated engine.

Engine design featuring intelligent details

The new engine excels with numerous intelligent design features. In contrast to the likewise transversely installed four-cylinder in the 35 models, the new engine has been turned 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.

The new twinscroll turbocharger combines optimum responsiveness at low engine speeds with a high power in the upper rpm range. The shaft of the compressor and turbine wheel is installed for the first time on anti-friction bearings, thus minimising mechanical friction in the turbocharger. The charger therefore responds more readily and reaches its maximum speed of up to 169,000 rpm more rapidly.

Electronically controlled charge-air pressure

With a maximum charge pressure of 2.1 bar, the 2.0-litre four-cylinder turbo engine is also the leader in its segment in this respect. The electronically controlled wastegate (exhaust relief valve) allows the charge pressure to be controlled even more precisely and flexibly while optimising responsiveness, especially when accelerating from partial load. Numerous parameters are taken into account in this process.

Fresh air is used in addition to oil and water to cool the turbocharger. This is directed specifically to the charger from the radiator grille, via the engine cover designed as an air deflector and ducts beneath the bonnet. In addition the turbine housing has integral insulation.

Larger exhaust valves for faster gas cycles

In the cylinder head, the repositioned and slightly angled injection nozzles and spark plug system have allowed much larger exhaust valves than in the preceding engine. The larger exhaust cross-sections allow the gases to stream out of the combustion chambers with minimum loss.

Two overhead camshafts control the 16 valves via weight-optimised roller cam followers. Camshaft adjustment on the inlet and outlet side allows an excellent response and optimises the gas cycle for each operating point. Variable CAMTRONIC valve control on the exhaust side is another feature, with two cams per valve. The cams have different geometries, so that depending on the cam setting to suit the driving situation, the exhaust valves can be opened for short or long periods – for even better responsiveness at low engine speeds, comfortable and fuel-efficient driving at medium rpm and full power delivery in the upper rpm range.

Two-stage fuel injection for optimised performance

For the first time, the new high-performance four-cylinder has two-stage fuel injection. In the first stage the particularly fast and precisely operating piezo injectors supply fuel to the combustion chambers at a pressure of up to 200 bar. This is a multiple process at times, and is controlled by the engine management system as required. In the second stage there is additional intake manifold injection using solenoid valves. This is needed to achieve the engine’s high specific output. The electronically controlled fuel supply has an operating pressure of 6.7 bar.

Sophisticated cooling system for engine, turbocharger and charge air

The high output requires an intelligently conceived cooling system. This is designed so that the cylinder head and crankcase can be cooled to different temperature levels. This innovative measure allows a cold cylinder head for maximum output with efficient ignition timing, and a warm crankcase to reduce in-engine friction.

The coolant to the cylinder head is supplied by a mechanical water pump, while cooling of the crankcase is via a second, electrically driven high-performance water pump. After a cold start, this pump remains passive until the engine has warmed up. In operation it is regulated by the engine control unit so that the crankcase is always cooled according to need.

In addition the engine has an oil temperature management function which controls the warm-up phase and flexibly regulates the engine oil temperature. This brings the engine to its operating temperature more rapidly, reducing friction and wear. This is accompanied by the environmentally friendly ancillary effect that fuel consumption and cold start emissions are also reduced.

Functions such as alternator management, the ECO start/stop function with fast restarting, the gliding function and a petrol particulate filter are also part of the technology package for the new AMG four-cylinder.

Digital and smart hand assembly: “One man, one engine”

The new engine is entirely assembled by hand. To this end a completely newly designed production line was constructed in the AMG engine manufactory in Affalterbach, where Mercedes-AMG has raised the “One Man, One Engine” principle and Industry 4.0 processes to an innovative level reflecting the latest findings in ergonomics, material flows, quality assurance, sustainability and efficiency. On the road to implementing Industry 4.0, AMG’s hand assembly operation likewise follows the vision of “smart production”. This excels with maximum flexibility, and is transparent and highly efficient. It safeguards and improves the quality of the engines and production processes using innovative and digital technologies.

Agile AMG SPEEDSHIFT DCT 8G dual-clutch transmission

The 8-speed AMG SPEEDSHIFT DCT 8G dual-clutch transmission likewise contributes to the agile and dynamic character. The gear ratios have been configured so that the driver experiences very spontaneous acceleration in all speed ranges, combined with fast shifting and optimum connections when shifting up. Depending on the selected AMG DYNAMIC SELECT driving mode, the driver receives a specific drive configuration with different accelerator and gearshift characteristics.

The standard RACE-START function allows maximum acceleration from stationary, a highly emotional experience. This also applies to the drive sound with partial ignition interruption when changing up a gear, and the automatic double-declutching function when changing down. Neither is efficiency neglected: in “Comfort” mode the ECO start/stop function is active; the “gliding” function can be selected in the “Individual” driving mode.

AMG Performance 4MATIC+ all-wheel drive with AMG TORQUE CONTROL

The extremely dynamic driving experience in a completely new dimension is greatly assisted by the fully variable all-wheel drive included as standard. The secret is AMG TORQUE CONTROL in the new rear axle differential: This has two electronically controlled multidisc clutches, each of which is connected to a rear axle drive shaft. In this way, the power can not only be completely variably distributed between the front and rear wheels, but also selectively between the left and right rear wheel. This means that depending on the drive mode, the traction can be separately distributed to both rear wheels.

The result is consistently optimum traction, even in adverse road conditions and during extreme cornering manoeuvres, for example on the racetrack. Furthermore, this sophisticated solution allows Drift mode (standard in the S-Models, included in the optional AMG DYNAMIC PLUS package for the basic models), which makes “powersliding” possible for even more driving pleasure. Drift mode can be called up in the “RACE” driving mode using the shift paddles, provided that ESP® is deactivated and the transmission is in manual mode.

Highly responsive electro-mechanical control

Control of the drive torque to the front and rear axle, and between the two rear wheels, is electro-mechanical. The influencing factors for torque distribution are not only the driving speed, the lateral and longitudinal acceleration and the steering angle, but also the difference in rotational speed between the individual wheels, the gear selected and the accelerator position.

The main advantages of electro-mechanical control over an electro-hydraulic system relate to more refined driving dynamics – primarily due to the significantly faster response and speed-independent actuation of the discs over the entire adjustment range.

The characteristics of the all-wheel drive control are dependent on the driving mode and the AMG DYNAMICS setting. In “Basic” and “Advanced”, the 4MATIC system is in “Comfort” mode. In “Pro” and “Master” (standard for S-Model, included in the optional AMG DYNAMIC PLUS package for the base model) the 4MATIC system switches to “Sport” mode – for even more agile handling and an even higher threshold for the critical limits.

Specific components for highly dynamic handling

The new AMG suspension with specific spring elements and the new, frequency-selective shock absorbers provides the basis for high directional stability and highly dynamic cornering characteristics with low body roll. At the same time comfort has been improved compared to the preceding model. The longitudinal and transverse dynamics are perfectly coordinated. All suspension components have been thoroughly revised in order to achieve a higher maximum lateral acceleration together with easy vehicle control at the limits.

A McPherson strut design is used at the front axle. Suspension is taken care of by one wishbone below the wheel centre, one spring strut and one tie rod respectively. The special axle geometry reduces torque steer – for high comfort and agile handling. The new wishbone in aluminium reduces the unsprung masses enabling a more sensitive response from the springs. The brake callipers at the front axle are radially bolted – a technology from motorsport for more stability. The front axle carrier is rigidly attached and thus additionally stiffens the front section.

The 4-link rear suspension is likewise rigidly connected to the body via a rear axle carrier, and therefore very torsionally rigid. There are three transverse control arms and one trailing arm plus specific bearings per rear wheel. This design ensures maximum driving stability and agility.

Adaptive damping system AMG RIDE CONTROL with three modes

The optional AMG RIDE CONTROL adaptive damping system enables the driver to choose between three different suspension control modes. The spectrum ranges from comfort-focused to sporty. The system operates fully automatically, adapting the damping forces for each wheel according to the driving situation and road conditions. This happens within milliseconds and is infinitely variable, with a wide spread of damping characteristics. The result is that it ride comfort and agility are enhanced in equal measure.

Robust high-performance brake system

The high-performance braking system ensures fade-resistant deceleration and short braking distances. On the base model, the 4-piston monobloc fixed front callipers act on 350 x 34 millimetre brake discs, while at the rear axle, 1-piston floating callipers act on 330 x 22 millimetre brake discs. The discs are internally ventilated and perforated to better dissipate heat and prevent brake fading, even with extreme use. The grey-painted brake callipers have white AMG lettering.

The S-Model and the base model with the optional AMG DYNAMIC PLUS package are decelerated by an even larger braking system equipped with 6-piston fixed callipers and 360 x 36 millimetre brake discs at the front. In this case the brake callipers are painted red and bear a black AMG logo.

Steering with special rack and variable ratio

The speed-sensitive, electro-mechanical sports power steering supports a sporty driving style with its direct turn-in ability. It has a special rack with variable transmission ratio and two characteristic curves: depending on which drive program the driver has selected, it provides taut and sporty or more comfort-biased steering feedback. The rigid mounting in the integral carrier connects the steering even better with the body and thus increases steering precision.

Vehicle characteristics with wide spread

The six AMG DYNAMIC SELECT drive programmes “Slippery”, “Comfort”, “Sport”, “Sport +”, “Individual” and “RACE” (standard for S-Model, included in the optional AMG DYNAMIC PLUS package for the base model) allow a wide spread of vehicle characteristics, from comfortable to dynamic. Numerous relevant parameters are modified:

• Powertrain: Accelerator pedal characteristic, shift times and shift timing in the variants Reduced, Moderate, Sport or Dynamic
• Transmission: automatic or manual
• AMG DYNAMICS: Agility functions such as all-wheel control, steering characteristics and additional ESP® functions in Basic, Advanced, Pro or Master variants (standard for S-Model, included in the optional AMG DYNAMIC PLUS package for base model)
• Exhaust system: Sound and nature of the sound functions, Balanced or Powerful
• Suspension (with optional AMG RIDE CONTROL suspension): in Comfort, Sport, Sport+

AMG DYNAMICS for enhanced agility and high stability

The new CLA45 4MATIC+ Shooting Brake features AMG DYNAMICS as part of the AMG DYNAMIC SELECT drive programmes. This integrated agility control facility extends the stabilising functions of ESP® with agility-enhancing intervention in the all-wheel-drive control, steering characteristics and additional ESP® functions. When cornering at speed, for example, brief braking intervention at the inner rear wheel generates a defined yawing motion around the vertical axis for responsive and precise entry into the bend.

The spectrum ranges from extremely stable to highly dynamic. On the multimedia display, when a drive program is selected, the new AMG DYNAMICS symbol is displayed together with the corresponding additional information.

• “Basic” is assigned to the “Slippery” and “Comfort” drive programs. In this case the compact sportscars exhibit very stable handling with a high level of yaw damping.
• “Advanced” is activated in the “Sport” program. The 45 models remain neutrally balanced. The lower yaw damping, lower steering angle requirement and enhanced agility support dynamic manoeuvres such as driving on winding country roads.
• “Pro” (short for “Professional”) belongs to the “Sport+” program. In “Pro” the driver receives even more assistance for dynamic driving manoeuvres while agility and feedback from the road when cornering are further enhanced.
• “Master” is linked to the “RACE” driving mode (standard for S-Model, included in the optional AMG DYNAMIC PLUS package for the base model). “Master” mode is aimed at drivers who want to experience dynamism and the driving enjoyment on closed-off circuits. “Master” offers a vehicle balance with slight oversteer, a low steering angle requirement and more agile steering. In this way, “Master” ensures maximum agility and fully exploits the dynamic potential. To activate “Master” mode, the driver must use the separate button in the centre console to switch the ESP® to ESP® SPORT Handling Mode or ESP®

In the “Individual” drive program, the driver can set the AMG DYNAMICS levels “Basic”, “Advanced”, “Pro” and “Master” themselves.

Man and machine in close alliance

With its sporty appointments and the MBUX infotainment system, the high-quality interior creates a close, personal connection between man and machine. The driver and front passenger are seated in an active position on contoured sport seats with firm lateral support. The standard upholstery as a combination of black ARTICO man-made leather and DINAMICA microfibre is timeless, and creates typical AMG highlights with double topstitching in red. The colour scheme is echoed by the red designo seat belts and the dashboard support trim in black DINAMICA microfibre with a red border. The chromed air vents are likewise upgraded with a red ring. As an alternative an upholstery in ARTICO man-made leather in neva grey/black with mid-grey double topstitching and light-longitudinal-grain aluminium trim is available.

Yellow highlights emphasise the motor racing heritage

Yellow highlights feature throughout the interior on the S-Model, emphasizing the motor racing character of the more powerful models. Also included in the standard equipment are the AMG Performance steering wheel in nappa leather/DINAMICA microfibre with contrasting yellow topstitching, a yellow 12 o’clock marking, AMG steering wheel buttons and AMG logo, plus ambience lighting.

In all models, the centre console in high-gloss black with a touchpad as standard has a further control array with additional switches controlling the 3-stage ESP®, the manual transmission mode, the optional adaptive damping system AMG RIDE CONTROL and the optional AMG Performance exhaust system. In combination with the optional leather package, it features a silver chrome console surround.

MBUX infotainment system with AMG-specific displays

The combination of sporty design and sophisticated details is also featured in the MBUX infotainment system with its innovative operating and display concept. MBUX creates an even closer connection between the vehicle, driver and passengers. Emotionally appealing presentations underline the clear control structure and feature brilliant maximum-resolution 3D graphics. Visually, the two displays under one shared glass cover blend into a Widescreen Cockpit and as a central element consequently emphasise the horizontal orientation of the interior design.

The customer can choose between the three AMG display styles “Classic”, “Sport” and “Supersport” for the instrument cluster. The “Supersport” mode is particularly striking with a central, round rev counter and additional information presented in the form of bars to the left and right of the rev counter: with a three-dimensional perspective, they reach far into the background to an artificial horizon.

And needless to say, the trailblazing voice control activated with the words “Hey Mercedes” is also on-board. Thanks to artificial intelligence, MBUX recognises and understands nearly all sentences from the fields of infotainment and vehicle operation, even if they are expressed indirectly.

AMG Performance steering wheel with optional control buttons

A perfect symbiosis between the driver and vehicle is ensured by the multifunction sport steering wheel in nappa leather with flattened steering wheel rim and perforated grip area, and depending on the upholstery, red, yellow or black topstitching and a facing in silver chrome. The galvanised steering wheel gearshift paddles allow an even sportier driving style with manual gear shifting.

As standard the S-Models are equipped with the AMG Performance steering wheel in nappa leather/DINAMICA microfibre (optional for basic model). The AMG steering wheel buttons (standard for S-Models, optional for the basic variants in conjunction with the Performance steering wheel) allow the AMG driving modes to be accessed directly, and other AMG functions to be conveniently operated directly at the steering wheel.