20 MPG combined isn’t going to win any awards in today’s automotive landscape, but within the specific context of the 2017 Mercedes-Benz SL550, it’s an accepted compromise. This isn’t a car designed for hypermiling; it’s a grand touring roadster packing a twin-turbo V8, meant for pleasurable weekend drives and comfortable cross-country jaunts. Potential owners are far more interested in leather quality and acceleration times than saving a few dollars at the pump. They prioritize the effortless power and sophisticated ride synonymous with the SL nameplate.

City and Highway Performance

The EPA estimates for the SL550 break down to 17 MPG in the city and 25 MPG on the highway. The 17 MPG city figure reflects the engine’s thirst when navigating stop-and-go traffic. The 4.7-liter V8 needs considerable fuel to deliver its robust power, especially with frequent acceleration from a standstill. On the open road, the nine-speed automatic transmission helps to keep the engine in its most efficient range, allowing for the slightly more palatable 25 MPG. That said, even on the highway, the temptation to exploit the engine’s performance will inevitably impact that number. Drivers who maintain a steady speed and resist the urge to pass aggressively will see figures closer to the EPA estimate.

Annual Fuel Cost

The EPA estimates that the 2017 Mercedes-Benz SL550 will cost $2,900 per year in fuel. This figure is based on driving 15,000 miles per year and using the national average fuel price. Bear in mind that this is simply an estimate; actual fuel costs will vary depending on driving habits, location, and fluctuations in gasoline prices. Someone who primarily drives in dense urban environments with frequent idling will likely exceed this number, while a driver who spends mostly time on the highway may see slightly lower costs.

Real-World Expectations

While the EPA provides a useful baseline, real-world fuel economy often differs. The SL550’s twin-turbo V8 is responsive and encourages drivers to explore its potential. Expect to see figures slightly below the EPA’s estimates, especially if you frequently enjoy spirited driving. A lead foot can easily drop highway MPG into the low 20s and city MPG into the low teens. Furthermore, road conditions, weather, and even tire pressure can impact fuel consumption. Consistent monitoring of your driving habits and vehicle maintenance can help to align your fuel economy with the manufacturer’s estimates.

How It Compares

Compared to other performance-oriented roadsters, the SL550’s fuel economy lands somewhere in the middle. The BMW Z4 M40i, with its inline-six engine, achieves a combined 25 MPG. The Porsche 911 Carrera Cabriolet, depending on configuration, can average around 21-22 MPG combined. A more powerful SL variant, such as the AMG SL63, with its even larger engine, will undoubtedly deliver lower MPG. This is a trade-off many buyers are prepared to make for the enhanced performance, but it further emphasizes the SL550’s position as a reasonable compromise between power and efficiency. If you’re interested in all Mercedes Benz fuel economy data, it’s easy to see how the SL550 fits into their lineup. Understanding the SL550 MPG across all years shows a trend of performance and relative fuel usage.

Tips to Maximize Efficiency

The SL550’s twin-turbo V8 can be surprisingly fuel-efficient if driven conservatively. Keep your acceleration smooth and avoid unnecessarily aggressive bursts of speed. The instant torque can be addictive, but resisting the urge to floor the accelerator at every opportunity will make a noticeable difference in fuel consumption.

Ensure that your tires are properly inflated to the manufacturer’s recommended pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Regularly check your tire pressure and adjust as needed, particularly during seasonal temperature changes.

Avoid unnecessary idling. If you’re stopped for more than a minute or two, turn off the engine. Modern engines are designed to restart quickly and efficiently, and restarting is often more fuel-efficient than idling for extended periods. This is especially relevant in urban environments with frequent traffic stops.

Utilize the SL550’s cruise control system whenever possible on the highway. Maintaining a steady speed reduces unnecessary acceleration and deceleration, optimizing fuel efficiency. Set the cruise control to a reasonable speed and allow the car to maintain a consistent pace.

Schedule regular maintenance and service appointments. A well-maintained engine runs more efficiently. Ensure that your air filter is clean, your spark plugs are in good condition, and your oil is changed according to the manufacturer’s recommendations. Addressing minor issues promptly can prevent them from escalating into more serious problems that impact fuel economy.