20 MPG combined isn’t going to win any hypermiling awards, but for the 2021 Porsche 911 Carrera 4S, it’s an acceptable compromise. This isn’t a car designed for maximizing fuel efficiency; it’s built for delivering exhilarating performance and a visceral driving experience. Those who sign on the dotted line for a 911 Carrera 4S prioritize breathtaking acceleration, precise handling, and the unmistakable Porsche heritage above all else. Fuel economy takes a back seat, though it’s still a consideration, especially when balancing daily driving with weekend canyon runs.

City and highway performance

The EPA estimates suggest 18 MPG in the city and 23 MPG on the highway for the 2021 911 Carrera 4S, equipped with its 3.0L twin-turbocharged flat-six engine and the 8-speed PDK automatic transmission. The city figure reflects the realities of stop-and-go traffic, where the engine spends more time idling or accelerating from a standstill. The highway figure is more optimistic, representing steady-state cruising where the engine can operate more efficiently. Still, expect these figures to change dramatically during spirited driving. A heavy foot will easily negate any attempts at fuel conservation.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2021 Porsche 911 Carrera 4S at $2,900. This figure is based on driving 15,000 miles per year and using national average fuel prices for premium gasoline, which this engine requires. This cost can fluctuate considerably depending on individual driving habits, local fuel prices, and the number of miles actually driven annually. Drivers who primarily use their 911 for shorter commutes or weekend enjoyment may find their actual fuel costs come in lower than the EPA estimate. Conversely, anyone using the 911 as a daily driver with significant mileage or, even more so, for frequent track days, will likely exceed the $2,900 figure.

Real-world expectations

While the EPA provides a standardized benchmark, real-world fuel economy can vary significantly. Factors like driving style, traffic conditions, and even tire pressure play an important role. Drivers who frequently engage the Sport or Sport Plus driving modes, characterized by more aggressive throttle mapping and higher engine RPMs, will inevitably see lower fuel economy than those who drive more conservatively. Similarly, driving in congested urban areas will also decrease fuel efficiency. Consider the EPA numbers a best-case scenario under controlled conditions. Exploring 911 MPG across all years, you can see how fuel economy has changed over time.

How it compares

Compared to other high-performance sports cars, the 2021 911 Carrera 4S’s fuel economy is competitive within its segment, but certainly not class-leading. For example, the BMW M4 Competition, with its 3.0L twin-turbo inline-six, achieves around 16 MPG city and 23 MPG highway. The Mercedes-AMG C63 S Coupe, powered by a 4.0L twin-turbo V8, typically returns fuel economy around 18 MPG city and 27 mpg Highway. Even all all Porsche fuel economy data shows the 911 sacrificing some efficiency for all-weather capability. The buyer cross-shopping these vehicles understands that performance comes at a cost, and fuel economy is a trade-off they are willing to make. The focus shifts from outright efficiency to the overall driving experience and the prestige associated with owning a Porsche, a BMW M, or an AMG.

Tips to maximize efficiency

Take it easy on the throttle. Even though the 911 Carrera 4S begs to be driven hard, gentle acceleration and smooth braking will significantly improve fuel economy. Avoid sudden bursts of speed and anticipate traffic to minimize unnecessary braking.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, which forces the engine to work harder and consume more fuel. Check your tire pressure regularly and inflate them to the recommended levels, which can be found on the driver’s side doorjamb or in the owner’s manual.

Limit idling time. Idling engines consume fuel without covering any distance. If you anticipate being stopped for more than a minute, turn off the engine. This can be particularly effective in city driving where you encounter frequent traffic lights.

Use the appropriate driving mode. The 911 Carrera 4S offers various driving modes, including a “Normal” or “Eco” mode. Selecting these modes will alter the engine mapping and transmission shift points to prioritize fuel efficiency over performance. Save the Sport and Sport Plus modes for when you truly want to unleash the car’s potential, not for everyday commuting.

Keep up with regular maintenance. A well-maintained engine operates more efficiently. Ensure that you follow the recommended maintenance schedule, including regular oil changes, air filter replacements, and spark plug replacements. A healthy engine will burn fuel more efficiently and deliver optimal performance.