2023 Mercedes-Benz AMG SL 43 Review

HELL, Mich. – The 2023 Mercedes-AMG SL 43 is the high-dollar luxury convertible equivalent to the Mustang turbo vs. V8 debate. In other words, don’t rule out this four-cylinder Benz just because it has half as many cylinders as its 55 and 63 siblings.

We’ve driven those, and while largely impressed with what those convertibles have to offer, they sure aren’t picture-perfect. Enter the 43 with its longitudinally-mounted 2.0-liter turbocharged (to-the-moon) four-cylinder engine. What makes the 43 desirable is less about what’s in it, though, and more about what isn’t – approximately 350 pounds of curb weight. That includes all that’s removed by having two fewer driven wheels – the V8-powered SLs are all-wheel-drive-only, whereas the 43 exclusively has rear-wheel drive. It also lacks the impossibly complicated active anti-roll stabilization system from the 63, instead sticking to just passive-everything as standard equipment.

The list goes on, but the vital point here is that a boatload of weight and complexity is removed from the equation, leaving you with a more straightforward driving experience.

All that said, there is nothing more complex than the technology AMG baked into the little engine up front. In an effort to ward off what we typically refer to as “turbo lag,” the engineers used an electric exhaust gas turbocharger. In layman’s terms, that means there’s a tiny, 1.6-inch electric motor integrated on the turbocharger shaft that gets the turbo spinning before the exhaust gases join the party and keep it spinning the old-fashioned way. The goal is to make throttle response immediate from idle or while driving after you’ve removed your foot from the throttle. That electric motor, operated via the 48-volt onboard electrical system – can take over at a second’s notice and maintain boost pressure at all times so you never have to spin it back up. It’s an idea derived from Mercedes’ F1 engine tech, and now you can buy it in a new car today. Neat!

Output for this hand-built AMG engine is a stout 375 horsepower and 354 pound-feet of torque. That’s impressive, but we can’t help wondering whether a halo car like the SL should have something less than the CLA 45 S coming to the U.S. that makes 416 hp and 369 lb-ft. Perhaps that number is just a little too close to the SL 55’s 469 ponies for Mercedes' comfort. Nevertheless, the SL 43 is claimed to run to 60 mph in just 4.8 seconds using launch control and top out at an electronically limited 170 mph. That’s 1.0 second slower than the 55 and 1.3 seconds behind the 63, but absolutely not slow and certainly not bad for dropping half an engine.

In a big plus for engagement, Mercedes sticks with its nine-speed multi-clutch transmission for shifting duties, giving you all the snappy rawness of the transmission fitted to its V8 models. It’s the perfect pairing for this four-cylinder engine, because short ratios and quick paddle response are your friends when power is in short reserve. Not to say there’s a lack of power, because the SL 43 will still briefly light up the rear tires when you spring away from a stoplight. Just make sure you tap it into traction control sport mode before doing so, because the ESC system hates fun with everything switched on.

The four-cylinder-ness really dominates the driving experience at all levels, even from the moment you switch the car on. Its idle is rough and loud, almost as if it’s missing balance shafts on purpose to convince you the engine is meaner and bigger than it is. Leave the exhaust in its quiet mode, and it makes very little noise at all when you’re cruising or under light acceleration. That constant thrum of the 4.0-liter twin-turbo V8 is missed here, as it makes the SL ooze with a more aggressive character. Get the revs up in the 43, though, and you’ll quickly learn that this engine has its own sweet tune to play. The buzziness at low speeds drops away, and a sweet, higher-pitched note comes on in the upper rev ranges, encouraging the driver to keep pulling the next paddle and play it again. It’s both racy and quick to charm. Mercedes found the right sound with this engine, because even though it may be the same size and have the same number of cylinders as hot hatches aplenty, it sounds like a sports car at full chat.

And as for how well that electric turbocharger works, it does its job. Even if you try your best to induce lag by hopping off the throttle for a couple seconds before fully stepping back into the right pedal, the engine does in fact pick back up right where it left off. Response is rapid off the line, as well, bettering what’s on offer in other high-powered AMG four-cylinders. It still doesn’t have the free-revving, telepathic response of a high-strung naturally-aspirated engine, but this sort of response is damn good for a massive turbocharger on a little engine.

The lighter front end is noticeable right away, but don’t think of it as revolutionary for the SL. Mercedes doesn’t list a weight for U.S.-spec cars, but the 3,990-pound curb weight in Europe still makes this convertible a hefty boy. A happier-to-turn-in nature is a lovely delight, though, and it makes the 43 even more enjoyable on a winding road than its brethren with more weight hanging off the front end. Just as Senior Editor James Riswick didn’t miss the 63’s active suspension bits in his first drive, I didn’t miss them in the SL 43 either. Its passive dampers split the difference between twisty road composure and poor-pavement compliance well, and if you do want something more advanced, the 43 can be equipped with the 53’s less complex, but arguably more agreeable AMG Ride Control adjustable and adaptive dampers. Really, the one big complaint that we’ll still lodge with this version of the SL, that can be applied across the range, is that it’s just plain heavy.

If you were hoping it being rear-drive instead of all-wheel-drive would bring some of the AMG GT magic back into the fold, reduce your expectations. The massive, grippy tires keep the rear end planted firmly on the straight and narrow in most cases, making it less tail-happy than you might expect. But perhaps any disappointment is really caused by the amount of power on tap. While 375 horses is a good number and its 0-60 time is certainly not slow, all-out acceleration is nevertheless behind the pace of cars like the Jaguar F-Type R Convertible, Porsche 911 Cabriolet and Chevrolet Corvette Convertible. The same lack of shove applies to the Lexus LC 500 Convertible, but that car speaks to you in ways this four-cylinder AMG simply cannot.

The reason those comparables are relevant is because this base SL 43 starts at $111,050 with our test car hitting $120,985. You’re going to have to want all the intangibles that the SL gives you outside of its solid – but still middling in the class – performance to choose it over rivals. Its design will easily turn every head on the block, and Mercedes still gives you quad tips (albeit round instead of rectangular) with the four-cylinder. There isn’t an interior that’ll beat this one for pure luxury and tech, so long as you can get past the annoying touchscreen roof operation. And did I mention it looks good?

For those reasons, it’s fantastic to see the SL 43 here in America. It broadens the SL’s appeal with a more playful chassis, rear-wheel drive and a smile-inducing four-cylinder at a massive discount – the cheapest V8 model starts at a towering $138,450. There’s even something for enthusiasts to nerd out about with the electric turbocharger. So don’t think of the SL 43 as second-fiddle to the V8 model you really want, because this four-cylinder might be exactly the answer and package you’re looking for.

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