27 MPG combined isn’t going to win any lower fuel costs awards, but for the 2018 Mercedes-Benz SLC300, it’s an acceptable compromise to experience open-top motoring with a touch of luxury. This isn’t a car bought by those laser-focused on maximizing fuel efficiency; it’s for individuals prioritizing style, performance, and the thrill of a retractable hardtop. They understand that engaging driving and premium features come at a price, in this case, at the pump.

City and highway performance

The EPA estimates the 2018 SLC300 will achieve 25 MPG in the city and 32 MPG on the highway. The city figure reflects the stop-and-go nature of urban driving, where the 2.0-liter turbocharged four-cylinder engine works a bit harder. The 9-speed automatic transmission, while offering smooth shifts, contributes to some efficiency loss in these conditions. However, on the open road, the SLC300 settles into a more relaxed cruise, allowing the engine to operate closer to its peak efficiency. 32 MPG on the highway is achievable if you resist the urge to fully exploit the turbocharger’s power, but spirited driving will quickly diminish this number.

Annual fuel cost

According to the EPA, the annual fuel cost for the 2018 Mercedes-Benz SLC300 is $2,150. This figure is based on driving 15,000 miles per year, with a roughly even split between city and highway driving, and using national average fuel prices. Premium fuel is recommended for the SLC300’s engine to achieve optimal performance, so your actual costs could be higher depending on local fuel prices and driving habits. It is also important to remember that the EPA figure is an estimate, your actual fuel expenditure will depend on your usage profile and geographical location.

Real-world expectations

While the EPA provides a useful benchmark, real-world fuel economy can vary significantly. Drivers with a heavy foot, those who frequently engage “Sport” mode, or those residing in areas with particularly hilly terrain will likely see figures below the EPA estimates. On the other hand, drivers who prioritize smooth acceleration, anticipate traffic flow, and use cruise control on the highway may be able to match or even slightly exceed the EPA numbers.

Expect a range of perhaps 23-29 MPG combined under typical driving conditions. For more information across model years, see SLC300 MPG across all years.

How it compares

In the realm of small luxury roadsters, the SLC300’s fuel economy falls somewhere in the middle. The BMW Z4 sDrive30i, with its 2.0-liter turbocharged engine, achieves a similar 28 MPG combined. The Fiat 124 Spider, sharing a platform with the Mazda MX-5 Miata (which gets around 30-34 MPG combined) but with a turbocharged engine, lands around 29 MPG combined. The Audi TT Roadster with its 2.0L turbo offers a comparable 26 MPG combined. These differences, while seemingly small, can add up over time.

However, the SLC300 buyer is often prioritizing the retractable hardtop and Mercedes-Benz prestige over outright fuel efficiency. If you are considering a broader range of vehicles, check out all Mercedes Benz fuel economy data before making your decision.

Tips to maximize efficiency

Take advantage of the “Comfort” driving mode whenever possible. This setting optimizes the engine and transmission for fuel efficiency, softening throttle response and encouraging earlier upshifts.

Resist the temptation to constantly tap into the turbocharger’s boost. Gradual acceleration and maintaining a steady speed will significantly improve fuel economy.

Ensure your tires are properly inflated to the recommended pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly, especially during temperature changes.

Reduce unnecessary weight in the vehicle. Excess cargo adds to the overall load the engine must carry, leading to increased fuel consumption. Remove any items you don’t need before embarking on a drive.

Plan your routes strategically to avoid traffic congestion. Stop-and-go traffic is a major fuel economy killer. Use navigation apps to identify alternate routes or less congested times of day.

Service your vehicle regularly according to the manufacturer’s recommendations. A well-maintained engine operates more efficiently. Ensure that air filters are clean, and oil changes are performed on schedule.