18 MPG combined won’t get accolades for lower fuel costs, but it’s what you get with the 2015 Audi RS 5 4.2L 8-cyl. This car prioritizes a visceral driving experience and the engine sound of a naturally aspirated V8. Its performance makes winding roads feel shorter. The RS 5 buyer likely isn’t thinking about saving gas, but instead wants a thrilling and meticulously engineered car, where fuel economy is just an expected cost.

City and highway performance

The EPA estimates for the 2015 RS 5 are 16 MPG in the city and 23 MPG on the highway. The city figure reflects the engine’s thirst for fuel with frequent acceleration from a stop. The highway number is better, but still falls behind competitors with smaller, turbocharged engines. The automatic (AM-S7) transmission provides fast shifts, but isn’t tuned for maximum fuel conservation. It’s tuned for responsiveness and readily downshifts to unleash the V8’s power. These MPG figures are because of how much performance the 4.2L V8 engine delivers.

Annual fuel cost

The EPA says the annual fuel cost for the 2015 Audi RS 5 is $3,200. This number assumes 15,000 miles per year, a mix of city and highway driving, and the national average fuel price for premium gasoline. Your actual fuel costs may change depending on how you drive, the fuel you use, and changes in average fuel prices. It’s hard to avoid the high costs of owning a performance car like the RS 5, especially since it needs a specific fuel type.

Real-world expectations

While the EPA estimates provide a starting point, real-world fuel economy will probably change. Driving hard, frequent short trips, and long idling will hurt fuel consumption. Some drivers might see slightly better numbers than the EPA estimates on long highway trips if they drive lightly. But, expect to be closer to, or even below, the 16 MPG city figure if you frequently use the engine’s power. The RS 5 encourages enthusiastic driving, so it’s unlikely that many owners consistently achieve the EPA’s combined rating. You can explore all Audi fuel economy data.

How it compares

The 2015 RS 5’s fuel economy is generally lower than other performance coupes of that time. A 2015 BMW M4 with its turbocharged inline-six engine gets a combined EPA rating of 20 MPG (with the manual transmission). Even the Mercedes-Benz C63 AMG Coupe with its larger V8 (though turbocharged from 2015 on), can get similar MPG numbers in some model-year variations because of improvements in engine technology. These details are less important to the RS 5 buyer, who values the unique character and high-revving of Audi’s naturally aspirated V8 over minor fuel efficiency improvements. Look at RS MPG across all years for comparison.

Tips to maximize efficiency

Fuel efficiency might not be your main goal, but there are still ways to help the RS 5’s MPG. Avoid short trips, where the engine doesn’t reach its best operating temperature, as the engine uses more fuel when cold, and short trips prevent proper warm-up for efficient running.

Maintain a steady speed on the highway and avoid accelerating too quickly. The RS 5’s V8 is responsive and loves to run, but constant speed changes make the transmission shift, reducing the vehicle’s efficiency.

Check your tire pressure, as underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly.

Follow the scheduled maintenance, including air filter replacements and spark plug changes. A well-maintained engine runs more efficiently and can achieve better fuel economy.