Affalterbach. After the two variants with a V8 engine, Mercedes-AMG presents the SL 43, a technically innovative entry-level model of the newly developed roadster icon. Under the hood of the open 2+2-seater with a fabric top, an in-line four-cylinder petrol engine with a displacement of two liters provides the befitting propulsion. For the first time in the world, an electric exhaust gas turbocharger is used in a production vehicle. This technology comes from Formula 1™. The system used in the SL 43 is a direct derivative of the development used successfully by the Mercedes-AMG Petronas F1 Team for many years in the pinnacle of motorsport. The new form of charging guarantees particularly spontaneous response across the entire engine speed range, thus offering an even more dynamic driving experience and at the same time increasing efficiency.
Mercedes AMG SL 43
The turbocharger is operated via the 48-volt vehicle electrical system, which also feeds the belt-driven starter generator (BSG). As a result, the Mercedes-AMG SL 43 has an output of 280 kW (381 hp) and a maximum torque of 480 Nm. In certain driving situations, there is also an additional short-term boost of 10 kW (14 hp) from the RSG. The new entry-level model in the SL family also shines with extensive standard equipment. In addition, numerous comfort and safety-enhancing options offer a wide range of customization options.
In the 70 years of its development history, the SL experienced the transformation from thoroughbred racing car to open-top luxury sports car – and not least because of this, it has long enjoyed legendary status. The new Mercedes-AMG SL now marks another milestone in the model history. It combines the pronounced sportiness of the original SL with the unique luxury and technological excellence of the modern Mercedes-AMG models. As the new entry-level model in the series, the SL 43 is a particularly good example of this. It is the world's first series-produced vehicle to have an electric exhaust gas turbocharger. This technology comes directly from Formula 1™ and solves the trade-off between a small, fast-acting supercharger that achieves comparatively low peak power, and a large supercharger with high peak power that only responds with a delay. With its innovative engine concept, the new entry-level model of the 2+2-seat roadster is aimed more and more at buyers with a particular affinity for technology. With its combination of a comparatively light four-cylinder engine on the front axle and rear-wheel drive, the SL 43 also demonstrates clearly independent handling.
“In its long history, the SL has repeatedly set technological milestones. For example, while the legendary 300 SL Gullwing in 1954 was the world's first production car with direct fuel injection, the new Mercedes-AMG SL 43 is now the very first production vehicle with an electric exhaust gas turbocharger. With this technology, the entry-level version of the SL has an excellent performance spectrum. Our supposedly smallest SL thus combines the AMG-typical driving performance with luxury and comfort at the absolute top level. In addition, we are undoubtedly appealing to a larger group of customers with this innovative engine,” says Philipp Schiemer, Chairman of the Board of Management of Mercedes-AMG GmbH.
“The electric exhaust gas turbocharger is a fascinating example of the extensive transfer between Formula 1 technology and the development of series vehicles. When implementing it in conjunction with our powerful M139 four-cylinder, we were also able to draw on the enormous wealth of experience of our colleagues from Mercedes-AMG High Performance Powertrains. The technology increases agility and thus driving pleasure, while at the same time improving the efficiency of the drive. With a view to our electrified future, we are pursuing ambitious goals. Innovative components such as the electric exhaust gas turbocharger help us to achieve this,” says Jochen Hermann, Chief Technical Officer of Mercedes-AMG GmbH.
Electric exhaust gas turbocharger improves engine response
The functional principle of the electric exhaust gas turbocharger is based on the same technology that is also used in the Mercedes-AMG Petronas F1 Team. An electric motor that is around four centimeters wide is integrated directly on the shaft of the turbocharger between the turbine wheel on the exhaust gas side and the compressor wheel on the fresh air side. Electronically controlled, this drives the shaft of the turbocharger directly, thus accelerating the compressor wheel before the exhaust gas flow takes over the conventional drive.
This significantly improves the response behavior right from idle speed and over the entire speed range. The combustion engine reacts even more spontaneously to commands from the accelerator pedal, and the overall driving experience is more dynamic. In addition, the electrification of the turbocharger enables higher torque at low engine speeds. This also increases agility and optimizes the ability to accelerate from a standing start. Even if the driver takes his foot off the gas or brakes, the technology of the e-turbocharger is able to maintain the charge pressure at all times. This ensures a continuously direct response.
The turbocharger, which is operated via the 48-volt vehicle electrical system, works at speeds of up to 170.000 rpm, which enables a very high air throughput. The charger, electric motor and power electronics are connected to the cooling circuit of the combustion engine in order to always create the best possible temperature environment. In combination with the internally named M139, two-liter four-cylinder in-line engine, the innovative technology in the SL 43 ensures a rated output of 280 kW (381 hp) at 6.750 rpm. The maximum torque of 480 Nm is available between 3.250 rpm and 5.000 rpm. Depending on the situation, the system also temporarily guarantees an additional boost of 10 kW (14 hp) from the belt-driven starter generator (BSG).
The second-generation RSG also functions as a mild hybrid in the 48-volt vehicle electrical system, which, in addition to the temporary boost in performance, also enables functions such as coasting and recuperation for maximum efficiency. At the same time, the 48-volt technology also increases comfort, since the transitions between the start-stop and coasting functions are almost imperceptible.
AMG SPEEDSHIFT MCT 9G transmission with wet starting clutch and rear-wheel drive
The four-cylinder known as the M139, which has long been installed transversely in the compact models from Mercedes-AMG without an electric exhaust gas turbocharger, is positioned longitudinally in the SL 43. In the entry-level model in the SL series, which is always driven by the rear wheels, it is also combined for the first time with the AMG SPEEDSHIFT MCT 9G transmission (MCT = Multi-Clutch Transmission). A wet starting clutch replaces the torque converter. It reduces the weight and, thanks to its lower mass inertia, optimizes the response to commands from the accelerator pedal, especially when sprinting and changing loads. The elaborately coordinated software ensures extremely short shift times and, if necessary, fast multiple downshifts.
In addition, the double-declutching function in the "Sport" and "Sport+" driving programs provides a particularly emotional shifting experience. In addition, the RACE START function is applied, which guarantees optimal acceleration from a standing start. The driving performance is befitting: from a standing start, the SL 43 accelerates to 4,9 km/h in just 100 seconds and has a top speed of 275 km/h. In addition to the required performance, the entry-level model in the series also features comparatively low fuel consumption and emissions.
Roadster architecture with composite aluminum structure for typical AMG driving performance
The new SL of the R232 series is based on a completely new vehicle architecture developed by Mercedes-AMG. For the first time since 1989 (Mercedes SL series R129), the new dimensional concept allows a 2+2 seat configuration. This makes the new SL even more versatile. The rear seats increase suitability for everyday use and offer space for people up to 1,50 meters tall (up to 1,35 meters with a child seat). If the additional seating is not needed, a plug-in wind deflector behind the rear seats can protect the front-seat passengers from draughts. Or the second row of seats is used as additional storage space and can hold a golf bag, for example. Constructed of lightweight composite aluminum, the chassis consists of an aluminum spaceframe with a self-supporting structure. The design guarantees maximum rigidity and is therefore the perfect basis for precise driving dynamics, a high level of comfort, optimal packaging and sporty body proportions. The aim of the bodyshell architecture is to present the typical AMG driving performance with a focus on lateral and longitudinal dynamics and at the same time to meet the high standards of comfort and safety.
With the new SL, the intelligent mix of materials enables maximum rigidity at a low weight. The materials used include aluminium, magnesium, fiber composites and steel, from which the windscreen frame, for example, is made. In conjunction with the bar system behind the rear seats, which can be deployed at lightning speed if necessary, this serves as rollover protection. Compared to the previous series, the torsional rigidity of the bodyshell has increased by 18 percent. The lateral rigidity is 50 percent higher than the already outstanding value of the AMG GT Roadster. Longitudinal rigidity is 40 percent higher. The weight of the pure shell is only around 270 kilograms. Together with the low center of gravity, the targeted lightweight construction ensures optimal driving dynamics.
Entry-level model with subtle distinguishing features in the exterior design
The exterior design of the SL 43 differs in individual details from the two eight-cylinder models. It has differentiated front and rear aprons as well as round instead of square twin tailpipe trims. The defining features of the SL body design include the long wheelbase, the short overhangs, the long bonnet, the passenger compartment set back with a steeply sloping windscreen and the powerful rear end. This results in the typical SL proportions.
They give the roadster its powerful, dynamic appearance – together with the voluminously modeled wheel arches and the large light-alloy wheels that are flush with the outer skin. The SL 43 rolls on 19-inch light-alloy wheels as standard. The same option is also available as for the eight-cylinder models: aerodynamically optimized light-alloy wheels with a diameter of 20 or 21 inches, which reduce air resistance with minimal turbulence. The 20-inch wheels with plastic aero rings, which save additional weight, are particularly sophisticated.
Active aerodynamics to increase dynamics and efficiency
A technical highlight for improving aerodynamics is the active air control system AIRPANEL. The horizontal slats behind the upper air intake are electronically controlled and can be opened and closed with servomotors. In this way, the air flow is guided as required, thereby improving aero performance. The slats are normally closed – even at top speed. This position reduces drag. Only when certain temperatures have been reached on predefined components and the cooling air requirement is particularly high do the fins open and allow maximum cooling air to flow to the heat exchangers. This requires highly intelligent and fast control. The same applies to another active aerodynamic component: the retractable rear spoiler that is seamlessly integrated into the vehicle silhouette. It changes its position depending on the driving situation.
The control software takes numerous parameters into account: It includes the driving speed, the longitudinal and lateral acceleration and the steering speed in the calculation. Above 80 km/h, the spoiler assumes five different angular positions in order to either optimize driving stability or reduce air resistance. The optional aerodynamics package for the Mercedes-AMG SL 43 includes larger flics on the front and rear bumpers and a larger rear diffuser. This further improves both downforce and air resistance. The changed speed thresholds of the rear spoiler and its steeper angle of 26,5 degrees (instead of 22 degrees) in the dynamic position also contribute to this.
Fabric hood for less weight and a lower center of gravity
The sportier positioning of the new SL also suggested the decision to go for an electric fabric top instead of the previous metal vario-roof. The 21 kg lower weight and the resulting lower center of gravity have a positive effect on driving dynamics and handling. The space and weight-saving Z-fold means that there is no need for a conventional convertible top compartment lid. The open top closes flush with the front roof cap in its final position. At the same time, the developers were faced with the task of maintaining the high suitability for everyday use and the exemplary noise level. The three-layer design consists of a tightly stretched outer shell, a precisely processed inner lining and the acoustic mat made of high-quality 450 g/m² PES fleece incorporated in between. Opening and closing only takes around 15 seconds and is possible at speeds of up to 60 km/h. The convertible top is operated using the switch panel in the center console or the multimedia touchscreen, on which an animation shows the progress of the process.
Interior with "hyperanalog" cockpit and standard comfort seats
The interior of the Mercedes-AMG SL 43 also awaits with the exciting combination of analogue geometry and the digital world – known as “hyperanalogue”. This is exemplified by the fully digital instrument cluster, which is integrated into a three-dimensional visor. With the standard MBUX infotainment system, there are several specific display styles and different modes to choose from. The symmetrical instrument panel is designed as a powerful wing and is structured into an upper and lower area. The highlight are the four galvanized turbine nozzles. Their surfaces merge into the instrument panel in the form of powerful power domes. The lower part of the instrument panel develops smoothly from the center console and seamlessly connects both elements.
Despite the symmetry, the cockpit design creates a clear focus on the driver: the high-resolution 12,3-inch LCD screen of the instrument cluster is not designed to be free-standing, but is integrated into a high-tech visor that prevents reflections from solar radiation. In order to avoid annoying light reflections caused by different positions of the sun when the top is down, the touchscreen on the center console can also be electrically adjusted from 12 degrees to 32 degrees. The latest generation MBUX (Mercedes-Benz User Experience) is intuitive to use and capable of learning. It offers numerous functional contents and the operating structure of the second-generation MBUX system, which made its debut in the new Mercedes-Benz S-Class. In the SL, extensive AMG-specific content is added in five display styles. Exclusive menu items such as "AMG Performance" or "AMG TRACK PACE" also underline the sporty character.
The SL 43 is equipped as standard with a variety of electrically and manually adjustable comfort seats in a combination of ARTICO man-made leather and fabric. Seat covers in leather, NAPPA leather and AMG NAPPA leather are optionally available, as are AMG sports seats and AMG performance seats with their sculptural design. The optionally available upholstery in MANUFAKTUR macchiato beige/titanium gray or in MANUFAKTUR tartufo brown/black provides a particularly exclusive touch. The AMG Performance seats can also be upholstered in a combination of nappa leather and DINAMICA microfibre with yellow or red topstitching. In addition to the standard high-gloss black, the decorative elements and the center console are also available in aluminum or carbon as well as in MANUFAKTUR chrome black. The AMG Performance steering wheel with optional steering wheel heating is available in nappa leather and nappa leather/MICROCUT microfibre.
Newly developed chassis with multi-link front axle and innovative lightweight construction measures
As standard, the SL 43 is equipped with a newly developed AMG RIDE CONTROL steel spring chassis with particularly powerful aluminum shock absorbers and lightweight coil springs. The new SL is the first production vehicle from Mercedes-AMG ever to have a multi-link front axle with five links that are arranged entirely within the wheel rim. This significantly improves the kinematics. A 5-link space construction also guides the wheels on the rear axle. In order to reduce the unsprung masses, all suspension links, steering knuckles and wheel carriers on the front and rear axles of the new SL are made of forged aluminium. The multi-link concept guides each wheel with minimal elastic movements. The high camber and toe rigidity not only enables high cornering speeds, it also gives the driver optimal contact with the road in the high cornering limit area. This is reflected in excellent lateral dynamics and driving stability at high speeds, as well as in the good-natured response to external influences such as crosswinds, bumps in the road or jumps in the coefficient of friction.
The lightweight coil springs are a new development: Thanks to a special heat treatment, their weight has been reduced without reducing their performance. In the manufacturing process, the spring pad is glued to the spring for the first time. This permanent connection avoids wear and tear caused by the ingress of dirt, such as sand, over the course of the vehicle's life. The spring does not corrode over its life cycle and the maximum component load can be increased at lower weight as a result. This saves around 0,2 kilograms per spring. Another lightweight construction measure concerns the torsion bar stabilizers on the front and rear axles of the SL 43. Their weight can be reduced thanks to variable wall thicknesses. The maximum wall thickness is only used where it is necessary due to the maximum load - in this case in the area of the rubber bearings.
The latest generation of AMG adaptive adjustable damping is available as an option for the SL 43. The chassis control unit adjusts the damping force for each wheel in just a few milliseconds using data analysis – including data from acceleration and wheel travel sensors. The driver can preselect the basic set-up via the AMG DYNAMIC SELECT drive programs: at the push of a button, for example, the handling changes from fully dynamic in "Sport+" mode to smooth cruising in the "Comfort" setting. In addition, the tuning can be adjusted in three stages using a separate button, independently of the driving programs.
AMG high-performance composite braking system for short braking distances
The newly developed AMG high-performance composite brake system guarantees excellent deceleration values and precise metering. It impresses with short braking distances, sensitive response behavior and last but not least with high stability and durability - even under extreme loads. The comfort functions include hill start assist, pre-filling and dry braking in the wet. When the ignition is switched off and the vehicle is stationary, the park position "P" is also activated. When driving off, the electric parking brake releases automatically.
The composite brake discs are particularly light: Driving dynamics and steering behavior benefit from the reduced unsprung masses. Brake disc (made of cast steel) and brake pot (made of aluminium) are now connected with special pins. This construction saves space, which is used for even better brake cooling. The directional perforation is also new: In addition to the weight savings and better heat dissipation, this solution scores with a faster response in the wet and better cleaning of the pads after braking.
Optional rear axle steering combines agility and stability
On request, the Mercedes-AMG SL 43 can be equipped with active rear-axle steering (HAL). Depending on the speed, the rear wheels steer either in the opposite direction (up to 100 km/h) or in the same direction (faster than 100 km/h) as the front wheels. The system thus enables agile and stable driving behavior in equal measure. The front-wheel steering ratio is more direct, making it easier to steer the vehicle at the limit with less steering effort.
Six drive programs and AMG DYNAMICS: from comfortable to dynamic
The five AMG DYNAMIC SELECT drive programs "Slippery", "Comfort", "Sport", "Sport +" and "Individual" as well as the "RACE" included in the optional AMG DYNAMIC PLUS package enable a wide range of vehicle characteristics from comfortable to dynamic. The individual driving programs offer an individual driving experience, precisely tailored to different driving conditions. As part of the AMG DYNAMIC SELECT drive programs, the SL models also have AMG DYNAMICS. This integrated driving dynamics control expands the stabilizing functions of ESP® with agile interventions in the steering characteristics and in additional ESP® functions. When cornering dynamically, for example, a brief application of the brakes on the rear wheel on the inside of the corner causes a defined yawing moment about the vertical axis for spontaneous and precise steering.
SL equipment range: great variety for an individual appearance
With the details of its extensive standard equipment and many additional options available, the Mercedes-AMG SL 43 offers a wide range of customization for the most diverse customer requests - from sporty and dynamic to luxuriously elegant. This includes twelve paint colors including the two exclusive SL shades hyper blue metallic and MANUFAKTUR monza gray magno, three roof color variants and some new wheel designs. There are three exterior design packages to choose from to sharpen the look further in the direction of elegance or dynamism:
- The AMG Exterior Chrome package contains elegant highlights in high-gloss chrome on the front apron, the side skirts and at the rear.
- With the AMG Night package, selected exterior elements are finished in high-gloss black, such as the front splitter, the side sill panels, the mirror caps and the trim in the rear diffuser. There are also darkened tailpipe trims. Depending on the paint chosen, this results in striking contrasts or flowing transitions.
- The AMG Night Package II also includes other elements in high-gloss black, including radiator grille, typography and a Mercedes star on the rear.
- With the AMG exterior carbon package, lightweight components made of carbon fiber are reminiscent of the motorsport history of the SL. The carbon parts include the front splitter and the flics in the front bumper as well as the trim strip in the side member paneling. There are also tailpipe trims in high-gloss black and the trim strip in the diffuser in carbon or in high-gloss black.
AMG DYNAMIC PLUS package for maximum driving pleasure
The AMG DYNAMIC PLUS package, which combines numerous high-performance components, is available as an option for the SL 43:
- Dynamic AMG engine mounts attach the engine to the body in a more rigid or flexible manner, depending on the driving situation. In every driving situation, this results in the best possible balance between driving dynamics and comfort.
- The electronically controlled AMG rear-axle locking differential distributes the required power even more promptly and precisely to the wheels during dynamic cornering and rapid acceleration, thus guaranteeing maximum traction.
- The "RACE" drive program delivers racetrack performance at the push of a button with an even more spontaneous engine response and the more direct accelerator pedal characteristic. Can be selected as an additional drive program using the AMG steering wheel buttons.
- The lowering by ten millimeters lowers the vehicle's center of gravity and also stabilizes the vehicle.
- The yellow painted AMG brake callipers visually underline the increased driving dynamics potential.
Driver assistance systems and MBUX: intelligent helpers in the background
The driver assistance systems, some of which are optional, use numerous sensors, cameras and radar to monitor the traffic and the area around the new SL 43. If necessary, the intelligent assistants can intervene at lightning speed. As in the current generations of Mercedes C- and S-Class, the driver is supported by a number of new and enhanced systems. This happens in everyday situations, for example by helping to adjust speed, distance control, steering and lane changing. This makes it easier to react to impending collisions. The functioning of the systems is visualized by a new display concept in the instrument cluster.
The new assistance display in the instrument cluster clearly and transparently shows how the driver assistance systems work in a full-screen view. The driver recognizes his car, lanes, lane markings and other road users such as cars, trucks and two-wheelers in a spatially abstracted manner. The system status and functionality of the assistants are visualized on the basis of this representation of the environment. The new animated assistance display is based on a 3D scene generated in real time. This high-quality and dynamic representation makes the functionality of the driver assistance systems transparent in an augmented reality driving experience.
Numerous connectivity services available
Technical data Mercedes AMG SL 43
|Of cylinders / arrangement||4 / R|
|rated capacity||kW / hp||280/381|
|at speed||1 / min||6.750|
|Additional power (boost)||kW / hp||10/14|
|at speed||1 / min||3.250-5.000|
|mixture preparation||Combined gasoline direct and intake manifold injection, charging using an electrically assisted exhaust gas turbocharger|
|Power Type||rear-wheel drive|
|Gear||AMG SPEEDSHIFT MCT 9G (automatic with wet multi-disc starting clutch)|
|Front||AMG RIDE CONTROL suspension with aluminum double wishbones, acceleration and braking torque support, lightweight coil springs and anti-roll bar|
|rear axle||AMG RIDE CONTROL suspension with aluminum double wishbones, acceleration and braking torque support, lightweight coil springs and anti-roll bar|
|Bremsanlage||hydraulic dual-circuit braking system; 390 mm composite brake discs at the front, internally ventilated and perforated, 6-piston aluminum fixed caliper; rear 360 mm composite brake discs, internally ventilated and perforated, 1-piston aluminum floating calliper; electric parking brake, ABS, Brake Assist, 3-stage ESP®|
|steering||electromechanical parameter power steering with rack, variable ratio (12,8:1 in zero position) and variable power steering|
|Rims||front: 9,5 J x 19; rear: 11 J x 19|
|Tires||front: 255/45 ZR 19; rear: 285/40 ZR 19|
|mass and weight|
|Front / rear track||mm||1.665/1.629|
|Length Height Width||mm||4.705/1.359/1.915|
|Weight ready to run according to EC||kg||1.810|
|Tank contents / of which reserve||l||70/10|
|Driving performance, consumption, emissions|
|Acceleration 0-100 km / h||dry||4,9|
|top speed||km / h||275 (electronically limited)|
|Combined fuel consumption WLTP||l / 100 km||9,4-8,9|
|CO2Emissions combined WLTP||g / km||214-201|
 The specified values are the determined "WLTP CO₂ values" in accordance with Art. 2 No. 3 Implementing Regulation (EU) 2017/1153. The fuel consumption values were calculated on the basis of these values.
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Mercedes-AMG SL 43: Attractive entry-level model with innovative engine technology
Photo credit: Mercedes-Benz
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