First marketed with a V8 as powerful as it is overpriced, the new SL agrees to become more reasonable by offering a four-cylinder. But with its 381 hp and its turbo assisted by an electric motor, this version of the Mercedes-AMG roadster should remain very efficient… and expensive.
In its long career, the SL has often adopted the noblest Mercedes engines. The four-cylinders are therefore not really his cup of tea. Only its W121 generation, sold from 1955 to 1963, the first to be offered in the form of a roadster, had already adopted such a “commoner” mechanical architecture. But today, a “four-legged” is back under the long hood of the latest version, codenamed R132. The Mercedes-AMG SL 43 is indeed equipped with a small 2.0 l turbo, even if he did not choose just any. He chose the M139, which has held the title of most powerful four-cylinder in the world since he landed in the 421 hp strong Mercedes-AMG A 45 S.
An electrified turbo like in Formula 1
To fit in the 2 + 2 star roadster, this engine had to be installed in a longitudinal position. It now drives only the rear wheels and is mated to a nine-speed MCT automatic transmission, in which the torque converter is replaced by a dry clutch, rather than the A-Class family’s dual-clutch 8G-DCT. Finally, it displays slightly lower power and torque with “only” 381 hp and 480 Nm. But in return it gains a light 48 V hybridization with an alternator-starter capable of providing 14 hp more in certain situations and, above all, an innovative turbocharger. As in Formula 1, the latter incorporates a small electric motor, only 4 cm thick, which intervenes when the volume of exhaust gases is not sufficient to drive the turbine fast enough. The response time of the turbo would thus be reduced to almost zero, offering better availability at low revs.
Performance drops, weight too
With its 585 hp biturbo V8, its 800 Nm of torque and its four-wheel drive, the 63 4Matic + version, the only one offered in France for the moment, necessarily keeps a clear head start in terms of performance. The maximum speed drops from 315 to 275 km/h on this SL 43 AMG, while the 0 to 100 km / h goes from 3.6 to 4.9 s. But the weight down to 1,810 kg, instead of 1,970 kg, could bring more agility, even without opting for the optional four-wheel steering. While mild hybridization and the halving of the number of cylinders reduce CO emissions2 significantly: the range is between 201 and 214 g/km on this 2.0 l version when the V8 4.0 l displays 282 to 294 g/km.
A more reasonable price and penalty
The penalty will no longer reach its ceiling of €40,000, but it will remain between €15,506 and €25,349. Without counting a tax on the weight of 100 € minimum, at the rate of 10 € per additional kilo beyond 1,800 kg. This sum will have to be added to a sale price which promises to be already salty, even if we should remain far from the 190,750 € requested by the 63 4Matic+ variant. With such a dissuasive taxation, it is therefore the future E Performance rechargeable hybrid version which risks doing well in France. However, we will have to wait a few more months to find out.
