Mercedes-Benz SL400: Twin-Turbo V6 Brings Fresh Entry to SL Range
The Mercedes-Benz SL400 replaces the SL350 as the entry point to the sixth-generation SL, pairing a new 3.0-litre twin-turbo V6 with familiar luxury and technology.
Mercedes-Benz has introduced the SL400 as the new entry-level model in the sixth-generation SL range, replacing the naturally aspirated SL350. The SL400 features a 3.0-litre twin-turbocharged V6, producing 333hp and 468Nm of torque, paired with the company's 7-speed automatic gearbox.
Engine and transmission
Despite its name, the SL400 does not use a 4.0-litre engine. The 2,996cc V6 uses two turbochargers to deliver a broad spread of torque, with peak output arriving from low in the rev range. With 333hp, the SL400 sits above the previous SL350 in outright performance, while the 7-speed automatic transmission provides smooth and rapid shifts. Mercedes-Benz's decision to use this gearbox across the range means the SL400 benefits from the same hardware as more expensive SL models. Gear changes are unobtrusive, though some rival systems offer sharper responses in manual mode.
The SL400's powertrain is tuned for refined progress rather than outright aggression. Overtaking performance is strong, but the chassis is capable of handling more power, as found in the SL500 and AMG models. For buyers seeking the most engaging drive, the entry-level SL's output may not fully exploit the platform's potential.
Fuel economy and real-world consumption
Mercedes-Benz quotes official combined fuel economy figures between 7.3 and 7.7 litres per 100km for the SL400. Real-world consumption varies: urban driving with a heavy right foot can see figures closer to 12L/100km, while steady motorway cruising at 100km/h can drop fuel use to around 5L/100km. These numbers put the SL400 on par with some family saloons in gentle use, though buyers of a six-figure roadster are unlikely to prioritise economy above refinement and performance.
Comfort and technology
Comfort remains a strong suit for the SL400. The car's adaptive suspension offers a choice between Comfort and Sport settings, allowing drivers to tailor the ride to road conditions and personal preference. The SL's folding hardtop, dual-zone climate control and effective noise insulation make it a usable grand tourer in all weather. Mercedes includes features such as heated and cooled seats, Airscarf neck-level heating, and a panoramic roof with variable tint, all aimed at making top-down motoring more appealing year-round.
The cabin design shares much with other Mercedes models of the era, with familiar switchgear and infotainment controls. While the layout is logical and the driving position is well-judged, some materials, such as dashboard plastics and faux wood trim, do not match the price point. The Harman/Kardon sound system, ambient lighting and storage solutions add to the sense of luxury, though rear visibility and storage for modern smartphones are limited.
Practicalities and daily use
The SL400's folding hardtop transforms it from a coupé to a convertible in seconds, with good wind protection and minimal buffeting at speed. The boot offers enough space for weekend luggage with the roof up, but capacity drops when the roof is stowed. Parking and low-speed manoeuvring are aided by sensors and a reversing camera, though the latter is not especially clear and rear three-quarter visibility is poor. The SL400 is best suited to open-road cruising rather than tight urban environments.
Where the SL400 fits in the Mercedes range
As the entry model in the SL line, the SL400 offers much of the comfort and technology of more expensive versions at a lower price. It sits below the SL500 and AMG variants, which offer larger engines and sharper performance. For buyers prioritising open-top comfort, refinement and style over outright speed, the SL400 makes a case as a daily-use grand tourer with the badge appeal and equipment expected of a Mercedes roadster.
- 3.0-litre twin-turbo V6 (333hp, 468Nm)
- 7-speed automatic gearbox
- Folding hardtop roof
- Adaptive suspension (Comfort/Sport)
- Heated and cooled seats with Airscarf
- Harman/Kardon audio system
