20 MPG combined is the fuel economy for the 2019 Mercedes-Benz SL550, a figure that probably surprises few drivers considering this is a luxurious, powerful roadster rather than a hybrid hatchback. SL550 buyers prioritize exhilarating performance, refined comfort, and iconic styling over gas mileage, understanding that the throaty rumble of the 4.7L V8 comes at a price.

City and highway performance

The SL550’s EPA estimates reflect its dual personality. City driving yields around 17 MPG, a consequence of frequent stop-and-go situations that demand more power from the engine. The 9-speed automatic transmission works to keep the engine in its most efficient range, but the engine’s sheer displacement and the car’s weight take their toll. Once on the open road, the SL550 fares better, achieving 25 MPG on the highway. This improved efficiency is due cruising at consistent speeds, allowing the engine to operate more comfortably and the transmission to settle into higher gears. While 25 MPG isn’t groundbreaking, it’s respectable for a car of this caliber designed more for spirited drives than cross-country treks.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2019 Mercedes-Benz SL550 will be $2,900. This figure is based on driving 15,000 miles per year and using national average fuel prices. Keep in mind that this a general estimate. Individual fuel costs will fluctuate depending on driving habits, local fuel prices, and the grade of gasoline used. The SL550’s thirst for premium fuel will further increase the yearly expense for many drivers.

Real-world expectations

While EPA estimates provide a useful baseline, most SL550 owners will likely experience fuel economy that varies somewhat from the official figures. Drivers with a heavier foot or those who frequently engage in spirited driving will likely see lower MPG, particularly in the city. Conversely, those who prioritize smooth acceleration and maintain consistent speeds on the highway might achieve slightly better results. It’s always a good idea to track your own fuel consumption using a smartphone app or simply noting mileage and fuel fill-ups to get a more accurate picture of your individual costs. Don’t forget to check SL550 MPG across all years.

How it compares

In the realm of luxury roadsters, the SL550’s fuel economy falls roughly in line with its competitors. For example, the BMW Z4 M40i, with its inline-6 engine, achieves around 25 MPG combined. The Porsche 911 Carrera S Cabriolet, a more focused performance machine, gets approximately 20 MPG combined as well. The Z4’s higher MPG reflects its smaller engine and less weight while the 911’s similar figure highlights that performance capabilities are prioritized over peak efficiency in this class. Buyers weighing these options should be aware that they involve trade-offs between outright performance, luxury features, and fuel consumption. Remember to check all Mercedes Benz fuel economy data as well.

Tips to maximize efficiency

While the SL550 isn’t designed for maximum fuel efficiency, there are several things owners can do to improve their MPG. Avoid aggressive acceleration and braking, as these drastically increase fuel consumption. Gentle, progressive inputs will allow the engine and transmission to operate more efficiently.

Proper tire inflation plays a surprisingly significant role in fuel economy. Check your tire pressures regularly and maintain them at the recommended levels listed on the doorjamb. Underinflated tires create more rolling resistance, forcing the engine to work harder and use more fuel.

Reduce unnecessary weight in the vehicle. Carrying extra cargo adds to the car’s overall weight, decreasing fuel efficiency. Removing items you don’t need will make a small but noticeable difference, particularly in city driving.

Plan your routes strategically to avoid stop-and-go traffic as much as possible. Idling in traffic consumes fuel without covering any distance. Using real-time traffic data to choose routes with fewer delays can save fuel over time

Consider using the SL550’s ECO driving mode, if equipped. This mode typically adjusts throttle response and shift points to prioritize fuel efficiency. While it may slightly reduce performance, it can help improve MPG, especially during daily commutes.