- Using F1 tech, the new 376-hp 4-cylinder electric turbo is brilliant
- The SL43 has flipped from Mercedes Benz to Mercedes-AMG
- The SL43 handles superbly
- Difficult to say how a 4-cylinder SL will be welcomed
- The exhaust note lacks the grunt of a V8
- Not yet available in the U.S.
When the news broke, Mercedes Benz SL fans couldn’t hide their shock. “You’re kidding! The new SL has a four-cylinder engine? Huh?! This is taking downsizing to the extreme,” were comments heard from hardcore SL owners. Eyebrows shot skywards as jaws hit the floor. The bewilderment was palpable.
That’s because last year, a 4-cylinder SL43 joined the SL lineup, a pedigree that traces its roots back to the legendary 300SL ‘Gullwing’ of 1954, while from 1971, it was characterized by a powerful V8. That’s right, for over 50 years, when an SL was mentioned, everyone thought of V8s.
In fact, there are actually two aspects of this luxury marque that compounded to make the automotive world buzz with nervous anticipation. In addition to Mercedes bravely adding the company’s first-ever four-cylinder, electrically turbocharged edition to the SL range, that “SL” nameplate, which had always been the iconic convertible of Mercedes-Benz, has now switched to Mercedes-AMG. That in itself is a huge leap in the right direction for many as AMG boasts loads of street cred. Needless to say, the V8-loving US market, where the SL55 and SL63 are already on sale, has not yet decided whether it will introduce the SL43 as well. So let’s check out this controversial new spec.
On face value, as you’d expect, this new e-turbo version looks pretty much like its V8-powered brothers in the SL55 and SL63. The only differences are the bumpers, exhaust pipes, and a badge on the side saying “Turbo Electrified.” But what I like most of all is its long nose and those bright yellow six-piston brake calipers. The whole package is neatly put together and looks compact on the outside, even though it’s actually a little bigger all around than its predecessor.
The exterior is sharp and straightforward, but the interior is bright red and hi-tech. The cabin is the same as other SLs, with a two-tier dashboard dominated by a portrait-orientated touchscreen in the center. Its red leather seats and black instrument panel with aluminum-colored accents give it a very upmarket feel. The 12.3-inch digital touchscreen is easy to use and the MBUX infotainment system’s voice guidance is quick to respond. AMG calls it a four-seater, but in reality, those rear seats are for emergencies only.
When I first heard about this four-cylinder e-turbo version, I was as surprised as anyone. Would SL fans accept the fact that the number of cylinders has been halved from eight to four? That’s kind of like a hamburger made with 100% beef, but is now made with 50% beef and the rest tofu and breadcrumbs. But Mercedes-AMG, with the tricky dose of spices and sauces has made it as tasty and beefy as possible, in an effort to try to close in on the 100% beef figure.
Powering the SL43 is the same AMG-developed four-cylinder engine found in the A45 and CLA45, but with a few key differences to both its layout and technology. You see, AMG borrowed electric turbocharging technology from the Petronas F1 car, combined it with a 48-volt mild-hybrid electrical system powered by a generator and dropped it the SL43 variant. Its 2.0-liter, four-cylinder engine generates 376-hp of 354 lb-ft of torque – with the ISG able to add an additional 14 hp for short bursts.
This new 4-cylinder system works by directly integrating a small electric motor directly into the turbocharger housing that can spin the turbo shaft from within until the exhaust gases eventually catch up and take over. This essentially eliminates turbo lag at low rpm, boosts torque at low engine revs and is even able to keep the turbo on boost when off-throttle. Truthfully speaking though, this AMG e-turbo is not actually the first-ever electrically driven turbo on a production car with that honor going to the 2017 Audi SQ7. What the AMG does add to the equation, however—making it unique—is that the SL43’s turbo is both driven by the exhaust and the electric motor.
Speaking of exhaust, the only aspect of this car that may leave some fans lukewarm is the exhaust note, which while metallic and meaty when pushed above 5000 rpm, still has nothing on its V8 brethren. Drivers do have the option of flicking through 3 modes, including an “S” and “S+” that livens up the handling and exhaust sound, but at the end of the day, the low-down thunder sounds made the SL55 and SL63 have been replaced by something resembling a rally car.
The SL43 employs a 9-speed automatic transmission powering the rear-wheels, making this the only rear-wheel drive SL available. The MCT 9G gearbox gives better throttle response as the heavy torque converter increases the inertia required to drive it, while the transmission itself enjoys shorter shift times and quicker downshifts via those electronically actuated clutches. This AMG also features a “Race Start” launch-control mode, which allows the SL43 to jump to 62 mph from a standstill in 4.9 seconds.
With its front and rear 5-link suspension setup employing optional 20-inch wheels, the SL43 does corner effortlessly and precisely with pinpoint response at speed. Its ride quality is arguably the best in the class too. With the flick of a switch you can drop the roof in just 15 seconds and set up a manually operated windbreaker that sits neatly behind the driver.
The pressure to downsize and improve emissions pushed AMG to make this SL43. While the F1-inspired, hi-tech 4-cylinder e-turbo is quick, responsive, and beautifully engineered and the car drives effortlessly in town or on the highway, some fans may find the exhaust note underwhelming — kind of like asking for the voice of Barry White and getting AC/DC’s Brian Johnson. If the SL43 does come to the US, it’ll land with a price tag hovering around $135,000.