The 2015 Porsche 911 Carrera S Cabriolet’s 22 MPG combined is a figure that reflects its performance capabilities. This isn’t a Prius, and most buyers of this $100,000+ German sports car prioritize exhilarating performance over fuel efficiency. However, it represents the realities of a 400 horsepower, naturally aspirated 3.8-liter flat-six engine. The Carrera S Cabriolet appeals to those who demand performance and prestige, accepting the fuel consumption as a trade-off for the driving experience.

City and highway performance

The EPA estimates the 2015 Carrera S Cabriolet at 19 MPG in the city and 27 MPG on the highway. These numbers show the different demands on the engine in varied driving situations. Stop-and-go city driving, with constant acceleration and deceleration, reduces fuel economy. Consistent highway speeds allow the engine to operate more efficiently, leading to better MPG. The automatic (AM-S7) transmission, Porsche’s PDK dual-clutch, helps with fuel efficiency by choosing the best gear for driving, even though it’s not the main reason for buying this car.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Porsche 911 Carrera S Cabriolet at $2,650. This is based on driving 15,000 miles per year and using national average fuel prices. Keep in mind that this is an estimate. Your actual fuel costs can change depending on your driving, the fuel type, and gas prices in your area. Premium fuel is highly recommended for the Carrera S’s engine, making this a potentially significant expense.

Real-world expectations

EPA estimates set a baseline, but real-world fuel economy for the 2015 Carrera S Cabriolet changes based on driving style. A heavy foot means lower MPG, but careful driving can get numbers closer to, or even better than, the EPA estimates. If drivers often put it in Sport or Sport Plus modes, which sharpen the throttle and lengthen gear holds, expect lower fuel efficiency. Drivers focused on performance might not care if the mileage drops below the EPA estimation.

How it compares

The 2015 911 Carrera S Cabriolet’s fuel economy is competitive within the class of high-performance convertibles, but others do better. The BMW M4 Convertible, with its turbocharged engine, achieves 25 MPG combined. A Jaguar F-Type R Convertible, with similar power and performance, tends to have lower real-world MPG. Expect even worse fuel economy from an Audi R8 Spyder, closer to 16 MPG combined. Manageable fuel use may appeal to some Porsche buyers, even thought it isn’t the primary reason to choose a 911 over these options.

Tips to maximize efficiency

Avoid hard acceleration and braking. The Carrera S’s strong engine is tempting, but moving smoothly will improve gas mileage. Watch traffic and keep a steady speed when possible, which cuts down on using bursts of power.

Correct tire inflation is very important for the best fuel efficiency. Check your tires often and inflate them to the recommended pressure on the doorjamb. Under-inflated tires cause more rolling resistance, which lowers MPG. Proper inflation helps any car and is important for maximum mileage.

Think about using “Normal” driving mode for daily driving. Sport and Sport Plus modes are fun, but take more fuel. Normal mode has enough power for most situations and uses less gas. You can always switch to “Sport” for merging or passing.

Reduce idling. Letting the engine idle wastes gas. If you’re stopped for over a minute, turn off the engine, especially in cities. Short periods of idling adds up and burns extra fuel.

Regular maintenance is very important for good fuel efficiency. Keep your engine tuned and follow all maintenance, including oil changes and air filter replacements, as specified by the manufacturer. See 911 MPG across all years for more information. For all Porsche fuel economy data, see our brand page.