Mercedes-AMG is developing a 600kW convertible

It was, in its heyday, the Mercedes-Benz model that represented the zenith of style and desirability offered by Germany’s oldest car company. The 300 SL ‘gullwing’ of 1954 remains an enduring icon, while the later W113 generation remained in production for a staggering 18 years.

The SL was a model that arguably peaked with the R129 generation; the Bruno Sacco-designed masterpiece built from 1989 to 2002 that epitomised fast, luxurious, open-topped motoring.

But like a fading Hollywood star, the SL has long been in decline. In 2012, for example, Benz shifted nearly 5000 SLs in the USA (the model’s largest market); last year, that tally was under 1700.

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So how to reverse this? Step one, hand over the development of the new model to Mercedes-AMG, and use the Affalterbach division’s expertise with all-aluminium platform construction to co-develop the new model, due in 2021, with the next-generation AMG GT.

The key point of difference from a packaging point of view will be the SL will remain a 2+2, continuing to provide small but useable kids’ seats in the rear, whereas the GT (and more comparable) GT Roadster will remain strictly two-seaters.

The other significant change will be a ditching of the Vario-Roof folding hardtop, marking a return to a lighter soft-top roof. This is partly down to the all-new aluminium structure; engineers are so confident of the stiffness of the SL’s new architecture, they’ve deemed a more torsionally rigid hardtop unnecessary. Further, advances in materials technology for the soft-top mean the designers believe they can get close to the noise-quelling qualities of a hardtop, but bank a useful weight saving.

Fully developed by AMG in Affalterbach, the next-gen SL will be based on a stretched and thoroughly updated version of the architecture beneath the two-seat AMG GT, which itself is related to the gullwinged SLS AMG, the first model engineered from a clean sheet in-house by AMG back in 2010.

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As for powertrains, sadly the new car won’t get the outgoing SL’s 6.0-litre V12, which Mercedes quietly dropped from the line-up back in 2018. Instead, a turbocharged straight-six and twin-turbo V8, both with 48-volt hybrid assistance, will ensure that even lower-spec SLs won’t lack performance.

Along with plans for Euro 7 compliant V8s, an EQ Power plug-in hybrid SL could be part of the mix, badged SL73 as a nod to the formidable 7.3-litre V12 model of 1995. This powertrain is expected to make its official debut in the AMG GT four-door later this year, combining the 470kW/900Nm M178 twin-turbo V8 with e-motors on both axles for around 600kW in total.

Speculatively, Australia could get a three-model SL line-up as per the current car, with the boosted inline-six opening the range, a 4.0-litre twin-turbo in the middle, and the top-spec mack-daddy SL73 there for customers prepared to part with what will surely be close to $400K.

So yes, monstrous performance will be there for those who seek it. The challenge for AMG will be engineering the new SL to exploit this, while retaining a softer, waftier character than that of the revamped GT.

To this end, expect the SL to have every tech trick thrown at it, including an even more sophisticated form of Merc’s Magic Body Control system that scans the road ahead for bumps and adjusts the damping rates accordingly. And given the new SL will eventually replace the S-Class coupe and convertible, the level of driver-assistance systems, materials and finishes will be truly next level.

AMG boss Tobias Moers acknowledges the importance of the task given to his division; to take such an esteemed Benz nameplate into the next generation. “It’s kind of a burden to be responsible for the SL, but we had to make sure this iconic car had a bright future,” he told media earlier this year. “The weight of responsibility is heavy but what we’re doing is good. We are taking the new all-aluminium SL back to its roots: more sporty but also better for everyday use.”

It’s not just AMG that will be involved with the next-gen SL, as Maybach is also expected to develop a variant for the drop-top, possibly with outlandish luxury design details inspired by the Vision Mercedes-Maybach 6 concept.