Mercedes-AMG reveals all-new tech-laden SL with traditional soft-top
Mercedes typically rolls out an all-new SL (Sports Light) only once every decade – the R107 generation endured almost twice that duration – so the unveiling of each successive iteration is eagerly anticipated.
The three-pointed star has just whipped the covers off the clean-sheet R232 model, and it dispenses with tradition in that it will be purely an AMG offering as it replaces not only the R231-gen SL, but also the AMG-GT Roadster.
In addition, the newcomer ditches the folding metal hardtop of the previous two SL generations in favour of a traditional fabric roof. Apart from simplifying packaging of the rear end, this also lowers the centre of gravity and reduces overall weight.
Mercedes-AMG has started from a blank sheet in conceiving the 2022 SL as it’s built around a completely new 2+2-seater architecture, and this hardware will also form the basis for the upcoming second-gen AMG-GT.
The manufacturer claims the new lightweight composite aluminium structure guarantees maximum rigidity and that it therefore forms “the perfect basis for precise driving dynamics, high comfort, optimal packaging and sporty body proportions.”
In addition, Mercedes-AMG is at pains to point out that “not a single component comes from the predecessor SL or any other model such as the AMG GT Roadster.”
In contrast to the current AMG-GT, which features a mid-front engine and transaxle layout (ie transmission housed in unison with rear axle), the new SL’s architecture features a more conventional format, with both engine and transmission (a nine-speed auto) sitting in tandem.
The new chassis/bodyshell architecture is fabricated from materials that include aluminium, magnesium, fibre composites and steel, from which the windscreen frame, for example, is made. This serves as roll-over protection in conjunction with the roll bar system behind the rear seats, which can be extended at lightning speed when needed.
Boding well for its dynamic prowess, transverse rigidity is 50 percent higher than the already taut AMG GT Roadster, while longitudinal rigidity is 40 percent higher.
The weight of the bare body shell is about 270kg, says its maker, while switching from its predecessor’s folding metal roof to an electrically deployed soft-top has yielded a 21kg reduction in weight, while also resulting in a lower centre of gravity that’s claimed to have a positive effect on driving dynamics and handling.
The space- and weight-saving Z-fold roof also makes it possible to dispense with a conventional soft-top compartment cover as the front roof cap ensures that the open soft top is flush with the surface in its final position.
In switching from metal to fabric, the developers were faced with the task of creating a roof that’s durable in day-to-day use, as well as insulating the cabin from road and wind noise. The three-layer design consists of a tightly stretched outer shell, precisely crafted roof liner and an acoustic mat made of high-quality 450 g/m² material inserted in between.
Opening and closing the roof takes about 15 seconds and is possible up to a speed of 60km/h. The soft top is operated using the switch panel in the centre console or the multimedia touchscreen, on which an animation shows how the process is progressing.
The new SL is said to benefit from Mercedes-AMG’s motorsport expertise in honing its aerodynamics, and it has a drag coefficient of 0.31 (no doubt with the roof up), which is a tidy figure for a convertible.
Regardless of whether the top is down or up, Mercedes-AMG claims the SL’s character and driving characteristics remain unchanged. In addition, Merc says the well-honed aero balance helps to defuse critical driving situations, such as a sudden evasive manoeuvre at high speed.
A key feature in the aero package is the two-piece, active air control that’s dubbed ‘AIRPANEL’. The first piece of this operates with vertical louvres hidden behind the lower air intake in the front apron. The second piece is located behind the upper air intake and has horizontal louvres.
Normally all louvres are closed, and this position reduces drag and allows the air to be directed specifically towards the underbody. This further reduces front lift.
Only when certain temperatures on predefined components are reached and the demand for cooling air is particularly high do the louvres open (the second system only from 180km/h) and allow maximum cooling air to flow to the heat exchangers.
Another active component is the retractable rear spoiler seamlessly integrated into the boot lid that changes its position depending on the driving status. In doing so, the control software takes into account numerous parameters: It factors the driving speed, the longitudinal and lateral acceleration and the steering speed into the calculation.
The spoiler assumes five different angular positions from 80km/h to either optimise handling stability or reduce drag.
An additional (optional) active aerodynamic element is a carbon winglet hidden in the underbody in front of the engine. This element, which weighs about 2kg, reacts to the setting of the AMG driving modes and automatically extends downwards by around 40mm at a speed of 80km/h.
As a result, in AMG drive modes, this creates the so-called ‘Venturi’ effect, which sucks the car additionally to the road surface and reduces front-axle lift. Mercedes-AMG claims the driver “feels this positively in the steering, as the SL can be steered even more precisely into bends and tracks even more stably”.
The SL’s dynamic package includes standard 4MATIC+ all-wheel-drive, AMG ACTIVE RIDE CONTROL suspension with active anti-roll stabilisation, rear-axle steering and the optionally available AMG ceramic high-performance composite brake system.
Mercedes-AMG says the 4MATIC+ all-wheel-drive system serves up fully variable torque distribution to the front and rear axles to ensure optimal traction right up to the limit. The driver is also able to rely on optimum handling stability and a high level of safety under all conditions, adds the company.
The new SL is also the first series-production Mercedes-AMG vehicle fitted with a multi-link front axle with five links arranged entirely within the rim. This is claimed to significantly improve the kinematics, and it’s complemented by a five-link design at the rear axle.
Another first for the SL is active rear-axle steering as standard. Depending on the speed, the rear wheels steer either in the opposite direction (at speeds of up to 100km/h) or in the same direction (faster than 100 km/h) as the front wheels. This makes the car more manoeuvrable in tight car parks, while being more stable at high speeds.
Meanwhile, hydraulically controlled anti-roll bars are said to provide optimal steering and load-change behaviour with AMG-typical driving characteristics in terms of dynamics, precision and feedback for the driver. At the same time, it increases ride comfort when driving in a straight line and over bumps.
At market launch, the new SL will be offered with two output levels of the familiar AMG 4.0-litre V8 biturbo engine.
In the range-topping SL 63 4MATIC+, the twin-turbo V8 thumps out 585hp and a stump-pulling 800Nm from 2500 to 4500rpm. Mercedes-AMG quotes a 0-100km/h split of 3.6sec for this model, while top speed is 315km/h. This compares to a 0-100km/h dash of 4.2sec and electronically limited v-max of 300km/h for the outgoing SL 63.
The SL 55 4MATIC+ ekes out 476hp and peak torque of 700Nm, yielding a 0-100km/h sprint in 3.9sec and top speed of 295km/h.
Although the force-fed 4.0-litre V8 is used in several Mercedes-AMG models, for the SL the engine receives a new oil pan, repositioned intercoolers and active crankcase ventilation. The intake and exhaust ducts have been optimised for even more effective gas exchange, and the exhaust gas routing for the catalytic converter box and petrol particulate filter has been enlarged.
The developers achieved the increased output of the SL 63 4MATIC+ primarily through higher boost pressure and greater air flow, as well as modified engine software.
In due course, the SL will also be available with an AMG E PERFORMANCE hybrid powertrain that’s allegedly “based on the guiding principle of offering an electrified powertrain that further enhances driving dynamics while also being highly efficient”.
The AMG SPEEDSHIFT MCT 9G transmission features a wet start-up clutch and is claimed to deliver “an emotionally appealing gearshift experience with extremely short shift times”.
The wet start-up clutch reduces weight vis-à-vis a torque converter and Mercedes-AMG claims its lower inertia optimises response to accelerator pedal commands, especially during spurts and load changes.
Keeping the SL’s massive V8 grunt in check is a newly developed AMG high-performance composite braking system that’s claimed to deliver excellent deceleration values and precise control. The new composite brake discs are also lighter than before and take up less space, allowing for even better brake cooling.
The SL is configurable in one of six driving modes – “Slippery”, “Comfort”, “Sport”, “Sport +”, “Individual” and “RACE” (standard for SL 63 4MATIC+, included in the optional AMG DYNAMIC PLUS package for SL 55 4MATIC+) – enabling a wide spread of vehicle characteristics from comfortable to dynamic.
Visually, the new SL has more in common with the current AMG-GT roadster than the outgoing R231 SL. Distinguished by a long snout, steeply raked windscreen, cab-rearward profile and short overhangs, it harks back to the 1957 300 SL that kickstarted Merc’s sporting roadster lineage.
Fronted by a thrusting grille with 14 vertical slats, the R232 has a distinctly more aggressive visage than the outgoing model. Voluptuously sculpted wheel arches and large alloy wheels flush that sit flush with the outer skin endow the roadster with a purposeful stance, and it looks well resolved whether the soft-top is lowered or deployed.
The cockpit is clearly driver-focused, yet the cabin layout is said to offer more room and functionality than in the outgoing SL. Don’t expect to accommodate basketballers in the rear seats, but Mercedes says they’re fine for individuals up to 1.50 metres tall.
The minimalist interior of the 300 SL Roadster is said to have inspired the cabin ambience of the new SL, and the result is a fusion of analogue geometry and digital wizardry that Mercedes refers to as “hyperanalogue”.
This is exemplified by the fully digital instrument cluster, which is integrated into a three-dimensional visor. The standard MBUX infotainment system offers a choice of several specific display styles and different modes.
As with past SLs, the latest roadster comes with ‘AIRSCARF’ as standard, blowing warm air into the passenger compartment from air outlets in the head restraints, enveloping the head and neck area of the driver and front passenger like a scarf.