22 MPG combined makes the 2025 Mercedes-Benz AMG SL43 2.0L 4-cyl an efficient roadster, particularly considering its performance pedigree and luxurious appointments. This isn’t a vehicle designed purely for economy runs, but rather for spirited drives and effortless grand touring. The fact that it achieves this figure, blending AMG dynamics with daily usability, speaks volumes about the advanced engineering at play.

City and Highway Performance

The AMG SL43 delivers 19 MPG in city driving and 27 MPG on the highway. Urban fuel consumption, while lower than its open-road counterpart, remains respectable for a car with 375 horsepower and a focus on responsiveness. The mild-hybrid assist, through the 48-volt integrated starter generator (ISG) and electric exhaust gas turbocharger, plays a crucial role here, smoothing out power delivery and, in some scenarios, acting as a subtle boost. This technology mitigates typical turbo lag that can often lead to heavier throttle inputs and higher fuel consumption in stop-and-go conditions. On the highway, the 27 MPG figure is where the SL43 truly shines. The 9-speed automatic transmission, with its broad gear ratios, allows the 2.0L four-cylinder engine to cruise at low RPMs, minimizing fuel burn while maintaining composure. This efficiency allows for extended road trips without frequent fuel stops, aligning perfectly with the SL’s original intent as a comfortable, powerful cruiser.

Annual Fuel Cost

The EPA estimates an annual fuel cost of $2,650 for the 2025 Mercedes-Benz AMG SL43. This figure is derived from assumptions of driving 15,000 miles per year, split between city and highway driving, using national average fuel prices, and factoring in the vehicle’s combined MPG rating. For the typical SL43 buyer, this annual expenditure is often a secondary consideration compared to the vehicle’s purchase price, performance, and luxury features. However, it provides a valuable benchmark for understanding running costs and underscores the efficiency gains achieved by modern powertrain technology within the performance luxury segment. When compared with the initial investment, this fuel cost presents a relatively small portion of the overall ownership experience.

Real-World Expectations

In the real world, owners of the 2025 Mercedes-Benz AMG SL43 can generally expect to see fuel economy figures that closely mirror the EPA estimates, provided their driving habits align with typical scenarios. The buyer of an SL43 isn’t chasing ultimate fuel economy; they’re enthusiasts who appreciate the combination of open-air motoring, sophisticated design, and exhilarating performance. They accept the fuel economy because the 2.0L engine, despite its smaller displacement, delivers a genuinely engaging driving experience thanks to its innovative electric turbocharger and strong 354 lb-ft of torque. This is a driver who values the precise handling, the crisp shifts of the AMG SPEEDSHIFT MCT 9G transmission, and the satisfying engine note, benefits that far outweigh marginal MPG differences compared to less engaging alternatives. For them, every gallon burned is an investment in a thrilling journey, where the convertible experience and the prestige of the AMG badge are paramount. You can explore all Mercedes-Benz fuel economy data on FuelEconomyHub.com.

How it Compares

Comparing the AMG SL43 to its direct rivals reveals a segment where performance often takes precedence over outright fuel economy, yet the SL43 carves out a notable niche. A competitor like the Porsche 911 Carrera (base model, automatic) offers around 21 MPG combined (18 city/25 highway), featuring a 3.0L twin-turbo flat-six. While the 911 slightly trails the SL43’s highway figure, its combined MPG is competitive. The BMW Z4 M40i, which is perhaps a closer conceptual rival in terms of engine size and roadster format, attains something closer to 26 MPG combined (23 city/31 highway) from its 3.0L inline-six, showcasing BMW’s efficiency prowess. However, the SL43 distinguishes itself with its more technologically advanced 2.0L engine, featuring an electric turbocharger derived from Formula 1. This innovation allows for a smaller engine to deliver comparable output to larger units while improving efficiency. This comparison underscores that the SL43 isn’t an outliers in terms of fuel consumption for its class; rather, it’s a sophisticated player using advanced technology to remain competitive while redefining performance for a luxury roadster. For those interested in the broader performance spectrum, AMG MPG across all years can be found here.

Tips to Maximize Efficiency

While the AMG SL43 is designed for dynamism, adopting certain driving practices can help owners maximize its inherent efficiency. Using the “Comfort” drive mode, which softens throttle response and optimizes shift points for economy, will yield better results than “Sport” or “Sport+.” These modes typically hold gears longer, increase engine RPMs, and are designed for performance, not parsimony.

Practicing smooth acceleration and gentle braking is another key factor. Aggressive starts and hard stops waste fuel. Using the SL43’s strong low-end torque in “Comfort” mode allows for effortless acceleration without fully engaging the electric turbocharger to its maximum boost, which can consume more fuel.

Regular maintenance is crucial for sustaining the vehicle’s fuel economy. Ensuring proper tire inflation, adhering to the recommended service intervals for oil changes, and keeping air filters clean are important. These simple steps ensure the engine and drivetrain operate at their peak efficiency, preventing unnecessary fuel consumption.

For highway driving, engaging the adaptive cruise control (if equipped) and maintaining a consistent speed will help. Fluctuating speeds requiring constant acceleration and deceleration are less efficient than a steady pace. The SL43’s highway efficiency is one of its strong suits, and using it wisely optimizes fuel use.