Looking to experience Mercedes-AMG's newest SL roadster on a budget? The company just announced a new entry-level model called the SL43, meant to slot below the V-8-powered SL55 and SL63. It packs the same M139 turbocharged four-cylinder found in the CLA45 and GLA45, making 381 hp and 353 lb-ft of torque in this application thanks to tech derived from Formula 1.
The technology, first shown off by Mercedes in 2020, is called electric turbocharging. Between the turbine wheel and the compressor wheel of the turbo you'll find an ultra-thin electric motor mounted directly to the shaft, there to spin the compressor wheel in addition to the exhaust gases. Having the motor to spin up the turbo eliminates any lag and improves response significantly. It's real Formula 1 tech for the road.
Mercedes says the system, assisted by the belt-driven 48-volt starter generator, can generate up to 14 additional horsepower for short periods of time for when you absolutely have to make that last-second pass. The company also claims a 0-62 time of 4.9 seconds and a top speed of 170 mph.
This is the first time Mercedes has positioned its famed M139 engine longitudinally in a production vehicle and the first time the motor has been mated to the company's nine-speed Speedshift multi-clutch transmission. Like in other SL models, power is sent solely to the rear wheels. You'll find six-piston brake calipers gripping 15.3-inch rotors up front, and 1-piston calipers in the rear paired to 14.1-inch rotors.
The SL43 shares much of its design with its more powerful siblings. Among the subtle changes are slightly altered front and rear fascias, along with rounded tailpipes out back. The alloy wheels measure 19 inches all around as standard, but 20- and 21-inch wheels are available as options. Also optional is an aerodynamics package that gives the SL43 larger flics on the bumpers, as well as a bigger diffuser. Ticking this box also gives the spoiler a steeper angle of attack (26.5 degrees vs. the standard 22 degrees) when in its deployed position.
Mercedes has yet to reveal pricing for the SL43, but we expect it to be steeply discounted over its bigger-engined siblings. It's still unclear at this time whether the trim will even make it to the U.S., with a spokesperson telling Road & Track via email the car is "currently still under consideration" for our market. If Mercedes does decide to bring the SL43 Stateside, it's likely to appear on our shores before the end of the year.