21 MPG combined isn’t going to win any fuel economy awards, but for the 2017 Porsche 911 Turbo S Cabriolet, it barely registers as a concern. This isn’t a car purchased for sensible commuting; it’s a statement, a thrill machine, and a showcase of Porsche’s engineering. Buyers signing up for a 580-horsepower, open-top rocket capable of hitting 60 mph in under three seconds understand the trade-offs. They prioritize performance and exclusivity over saving at the pump.

City and highway performance

The EPA estimates that the 911 Turbo S Cabriolet achieves 19 MPG in the city and 24 MPG on the highway. Consider the nature of this machine. In city driving, the stop-and-go nature and the near-instantaneous torque of the turbocharged engine will tempt drivers to accelerate. Hence, the lower city MPG.

On the open road, where the aerodynamics can contribute more effectively, and the engine settles into a less frantic rhythm, the 24 MPG is a reasonable expectation. Even then, the temptation to unleash its power looms, impacting real-world figures.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2017 Porsche 911 Turbo S Cabriolet to be $2,750. This figure is based on driving 15,000 miles per year, using a national average fuel price. Owners of this car may not drive it as their daily commuter, and gasoline prices fluctuate, so the cost may climb higher for those who premium fuel (as required) and enjoy frequent spirited drives. Consider this figure a baseline, not a budget.

Real-world expectations

Forget chasing the EPA numbers. Driving a 911 Turbo S Cabriolet is about the experience, not hypermiling. Real-world fuel economy will depend heavily on driving style. Expect lower numbers if you spend most of your time in Sport or Sport Plus mode, frequently using the car’s performance. Extended highway cruising at legal speeds will yield numbers closer to the EPA estimate. Aggressive acceleration and high-speed runs will drain the tank rapidly.

How it compares

The 911 Turbo S isn’t drastically out of line against other performance cabriolets, but context matters. The Mercedes-AMG SL63, with its hand-built V8, delivers around 16 MPG combined; a BMW M8 Competition Convertible lands around 17 MPG combined. These competitors highlight that extreme performance has a cost, and those in this segment are often willing to pay it.

For those seeking similar performance with slightly better fuel economy, the standard 911 Carrera S Cabriolet returns closer to 21 MPG combined, but at a sacrifice in raw power. Marginal differences in fuel economy are unlikely to sway someone already considering the Turbo S model. You can compare that to 911 MPG across all years if you would like.

Tips to maximize efficiency

While maximizing fuel efficiency might not be the primary goal of a 911 Turbo S owner, there are strategies to squeeze more miles from each gallon.

Using the vehicle’s driving modes is key. “Normal” mode relaxes throttle response and optimizes the transmission for efficiency, ideal for steady-state highway driving.

Avoid unnecessary idling, especially when the engine is cold. Modern engines warm up quickly while driving, making prolonged idling wasteful.

Starting and stopping frequently burns more fuel than driving at a consistent speed, and Porsche has also considered idle stop-start technology, but at this time, some features such as this one have not been implemented.

Regularly check tire pressures. Underinflated tires increase rolling resistance, reducing fuel economy. Maintaining the correct pressure ensures the car rolls more freely and evenly, saving fuel and improving handling.

Removing unnecessary items from the car can reduce its overall weight, improving fuel economy, though the gains may be small in such a high-performance vehicle. Excess weight impacts acceleration more than steady-state cruising.

Smooth, consistent driving is important. Anticipate traffic flow and avoid abrupt acceleration and braking. Gentle acceleration and coasting whenever possible will not only save fuel but also enhance the overall driving experience. You can also view all Porsche fuel economy data on our website.