With a combined 23 MPG, the 2018 Acura RLX, powered by its 3.5L V6, isn’t the most fuel-efficient, but it offers respectable gas mileage for a full-size luxury sedan with a naturally aspirated engine. This number is less a primary selling point and more an acknowledgement that good power and quiet driving don’t necessarily require excessive gasoline use. The RLX buyer isn’t chasing ultimate thriftiness; they value refinement, reliability, and a sense of understated luxury, and are willing to accept decent, if not class-leading, fuel economy as part of the package.

City and highway performance

The EPA estimates the RLX at 20 MPG in the city and 29 MPG on the highway. These numbers reflect the car’s intended use. Around town, the V6 provides smooth, responsive power, making merging and navigating traffic easy. The ten-speed automatic transmission is well-tuned, offering shifts that contribute to the relaxed driving experience. The highway figure shows the RLX’s ability to cruise long distances. At steady speeds, the engine settles into a quiet hum, and the efficient transmission keeps the RPMs low, maximizing fuel economy. While 29 MPG is achievable, aggressive acceleration or headwinds will certainly reduce this number.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Acura RLX at $2,500. This figure is based on driving 15,000 miles per year and using the national average fuel price at the time of calculation. Remember that your actual fuel costs will vary depending on your driving habits, the type of roads you drive on, and the price of gasoline in your area. While $2,500 is a significant expense, it’s within the expected range for a vehicle in this class, particularly one that doesn’t require premium fuel.

Real-world expectations

While the EPA estimates provide a useful benchmark, real-world fuel economy often differs. Expect to see numbers that fluctuate based on your driving style and conditions. Aggressive acceleration, frequent stop-and-go traffic, and extended idling can all negatively impact fuel economy.

On the other hand, smooth, consistent driving on the highway can help you achieve or even slightly exceed the EPA’s 29 MPG estimate. Many owners report averaging around 22-25 MPG in mixed driving conditions, which aligns well with the EPA’s combined rating.

Remember, these are averages, and individual results can vary considerably. Always check RLX MPG across all years to understand the MPG history of the car.

How it compares

Compared to its competitors, the 2018 Acura RLX’s fuel economy is competitive, but not groundbreaking. The Lexus GS 350, for example, is rated at 23 MPG combined, matching the RLX, but offers slightly better highway numbers at 30 MPG. The BMW 540i, with its turbocharged engine, achieves a similar 24 MPG combined, showing the efficiency gains that can come with forced induction. The Genesis G80 3.3T offers comparable power but slightly lower fuel economy, rated at 20 MPG combined. The choice comes down to priorities: if fuel efficiency is important, some competitors offer a slight edge. However, the RLX counters with its reputation for reliability and lower maintenance costs. Before buying, check all Acura fuel economy data.

Tips to maximize efficiency

Smooth and consistent acceleration is key to maximizing fuel economy in the RLX. Avoid sudden bursts of speed and try to maintain a steady pace. The RLX’s V6 engine responds well to gentle throttle inputs, and the ten-speed transmission will shift to keep the engine in its most efficient operating range.

Regular maintenance is essential for optimal fuel economy. Ensure that your RLX receives timely oil changes, air filter replacements, and tire rotations. A well-maintained engine runs more efficiently, and properly inflated tires reduce rolling resistance. Neglecting routine maintenance can lead to decreased fuel economy and potentially more serious mechanical issues down the road.

Minimize idling time whenever possible. Idling consumes fuel without covering any distance, so it significantly impacts fuel efficiency. If you anticipate being stopped for more than a minute, turn off the engine. The RLX’s quick and easy restart system makes this a convenient way to save fuel, especially in stop-and-go traffic.

Use cruise control on the highway to maintain a consistent speed. Cruise control helps prevent unnecessary acceleration and deceleration, which can improve fuel economy. However, be mindful of hills and adjust your speed accordingly to avoid excessive downshifting. On relatively flat roads, cruise control can be a valuable tool for maximizing fuel efficiency on long journeys.

Consider the drive mode selector. The RLX offers different driving modes that can impact fuel economy. The “Econ” mode prioritizes fuel efficiency by adjusting throttle response and transmission shift points. While it might slightly reduce performance, it can make a noticeable difference in fuel consumption over time, especially during city driving. Experiment with different modes to find the best balance between performance and efficiency for your driving style.