New 2021 Mercedes SL: the CAR lowdown | CAR Magazine

New 2021 Mercedes SL: the CAR lowdown

Published: 15 March 2021 Updated: 15 March 2021

Mercedes’ new SL convertible
Soft top, hybrid power and here in 2021
► Developed by AMG, twinned with GT

The Mercedes-AMG SL is nearly here. Our spy photographers have snapped Mercedes meaner, more aggressive roadster testing – and a lack of camo means it it can’t be far from an unveil. The pictures show a car that has the same footprint as the GT it shares a base with, though there are important differences. Both the front lights and rear have more in common with the brand’s saloons – while the overall styling is a touch more reserved.

What else do we know? 

 It will now be known exclusively as the Mercedes-AMG SL, highlighting Affalterbach engineers’ involvement in the process from the beginning, and will start with an SL300 variant.

The SL name has been around for decades, but 2021’s new generation promises to be the most clearly defined for a very long time. What’s brought Merc’s seventh-generation big convertible into focus is that it’s been developed from day one alongside the next-gen AMG GT. 

Although there will be some overlap in the hardware of the two model lines, the look and feel should be quite distinct, as the engineers have been conscious of the need for there to be a meaningful dynamic difference between SL and GT. They’re both powerful, luxurious products, but they have slightly different markets in mind. Don’t think of them as opposites; rather, this is two sides of the same coin.

Mercedes SL illustration

Since its birth in 1954, the SL has always been at heart a convertible built for high-speed cruising; the GT, first shown in 2014, is a coupe and roadster with more of an emphasis on performance. There have been times when the SL has gone too far down the plushness route, at the expense of sharpness, but that shouldn’t be the case this time around. 

The 2021 SL and 2022’s second-generation AMG GT are to share an engine line-up. In a big break with tradition, both the SL and GT will use 2.0-litre fours in most models. Doesn’t sound right? Perhaps. But since emissions control is of paramount importance and driving enthusiasts are warming to electrification, there is simply no need to resort to the straight-six this side of the 650bhp power threshold.


Instead, both aluminium-spaceframe sports cars combine e-modules with different four-cylinder combustion engines. In this process, the AMG GT loses its transaxle gearbox. On the credit side, 4Matic+ all-wheel drive is bound to boost take-off traction and lower 0-62mph times.

Only the base SL/GT 43 will remain rear-wheel drive. This version of the M254 engine puts out around 390bhp supported by a 20bhp integrated starter-generator (ISG). One step up, the SL/GT 53 is fitted with AMG’s own uprated M139 unit good for around 450bhp. Factor in some 40bhp of e-boosting for a total approaching 500bhp. The third and final four-cylinder can be found in the 600bhp SL53e 4Matic+, where the M139 teams up with an electrified rear axle rated at around 150bhp.

Where’s the V8, you ask? Here it comes. In the SL/GT 63 4Matic+, in which a blend of twin-turbo 4.0-litre eight and 20bhp starter-generator is claimed to deliver around 630bhp. These variants can reportedly complete the 0-62mph sprint in an impressive 3.5sec. The same V8 is in the SL/GT 73e 4Matic+ assisted by an electric 204bhp rear-axle power pack and a 40bhp starter-generator for a bottom line of around 825bhp. 

While the non-hybrid configurations are said to be up to 25% less thirsty than their octane-addicted predecessors, the EQ Power+ drivetrains slash the consumption by approximately two thirds. This strategy may not be what petrolheads want to hear, but Mercedes and AMG are getting increasingly smart about deploying electrification in ways that improve both efficiency and performance. 

Speaking to CAR before his departure to Aston Martin, AMG boss Tobias Moers told us: ‘The new car will be kind of the rebirth of SL, more sporty. For the current car, cruiser is a good expression. The new car will take the SL back to its roots. Everything is new this time, and all aluminium.’

It’s a 2+2, with the old retractable hardtop replaced by a power-operated soft-top. From what we’ve seen of the W232-series SL shaped by Gorden Wagener’s design team (illustrated here by an artist’s impression), there’s a squared-off front and a more rounded, slightly 911-like, rear end. Inside, expect a mix of analogue and digital themes, with the cockpit dominated by a huge S-Class-derived flatscreen, as the 67-year-old SL moves into a new era… with a little help from the GT.

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By Curtis Moldrich

CAR's Digital Editor, F1 and sim-racing enthusiast. Partial to clever tech and sports bikes