Nearly six decades after the last four-cylinder SL rolled off the production line in 1963 and Mercedes is re-introducing a four-banger in its flagship roadster lineup in the form of the new 2023 Mercedes-AMG SL43. Following the introduction of a pair of bi-turbocharged 4.0-liter V8s in the SL 55 4Matic+ and SL63 4Matic+ delivering 470-hp and 577-hp respectively in the R232-codenamed SL last year, the SL43 takes its place as the entry model of the 2+2 roadster range.
Powering the base SL is a new variant of
AMG’s 2.0-liter four-cylinder M139 engine that uses an electric exhaust gas
turbocharger, a technology derived from Formula 1 racing cars, which Mercedes
claims a first for a production vehicle. The turbocharger is operated through a
48-volt electrical system that feeds the second-generation belt-driven
starter-generator (RSG). Beyond providing a temporary boost in power, the
system also works as a mild-hybrid allowing a gliding mode and energy recovery
for increased efficiency.
The 2.0-liter unit that is positioned
longitudinally in the SL 43 produces 375-hp at 6,750 rpm and
480 Nm of peak torque between 3,250 and 5,000 rpm, plus an
additional short-term boost of 13-hp from the belt-driven
starter generator (RSG) in certain driving situations. For those of you
counting horses, that’s notably less than the 2.0-liter turbo found in the A45
S and CLA 45 S, which is rated at an impressive 415 hp and 500 Nm of torque making it currently the most powerful
four-cylinder in production. AMG’s 9-speed MCT automatic transmission drives
the rear wheels only with the Germans claiming a 0-100 km/h acceleration time of 4.9 seconds and a top speed of 275 km/h. As for
fuel economy, in the combined WLTP cycle, the SL43 returns between 9.4 and 8.9
l/100km, which is the U.S. equivalent of 25.0-26.4 mpg.
Elsewhere, the base version of AMG’s
fabric-top roadster comes fitted as standard with an AMG RIDE CONTROL steel
suspension and an AMG DYNAMIC SELECT system with five driving modes, or six if
you opt for the AMG DYNAMIC PLUS Package that adds “Race” to the existing
“Slippery”, “Comfort”, “Sport”, “Sport +” and “Individual”. The optional Plus
Package also throws in a few more goodies to the mix, including a 10mm lowered
suspension, different engine mounts, an electronically controlled limited-slip
rear differential and yellow brake calipers.
For those of you aspiring
to be that guy pointing out the four-cylinder block under the hood when someone
opts to delete the badging, the easiest way is to look at the back and spot the
round instead of the angular double tailpipe trim found in the V8s. The SL 43
also runs on smaller 19-inch wheels as standard, but you can also get the
larger 20 or 21 inch rims available in the eight-cylinder models as an option. Speaking
of extras, Mercedes hasn’t held back offering anything and everything from an
active rear-axle steering (HAL) system that turns the rear wheels either in the
opposite direction (up to 100 km/h) or in the same direction (faster
than 100 km/h) as the front wheels and MANUFAKTUR individual colors, to all sorts
of packages like the exterior Carbon and high-gloss chrome kits.
We wouldn’t be
surprised if Mercedes kept it out of the USA, as there’s a stigma against
four-cylinder engines in higher-end sports and luxury cars, especially at this
price point. Still, we’ve reached out to Mercedes and will update this story if
and when they get back to us. As for the European market, Mercedes will
communicate availability and pricing details at a later stage. Beyond the SL43,
Mercedes-AMG is also working on a plug-in hybrid variant of the R232 that could
be called the SL63 E-Performance featuring the same powertrain as the AMG GT 63
E Performance that combines a twin-turbocharged 4.0-liter V8 with an electric
motor making a massive 831 hp and 1,400 Nm of
torque.
