The Biggest Overachievers in Our Real-World Highway MPG Test

2022 genesi g70
Top 10 EPA Fuel-Economy OverachieversAndy Potts - Car and Driver

The Environmental Protection Agency (EPA) was created by President Richard Nixon in 1970 to curb confusing and often ineffective local and state environmental laws. The EPA stopped the use of harmful leaded gasoline, and worked with automakers to put a catalytic converter under every new car for the 1975 model year—an action that resulted in fewer tailpipe emissions, cleaner air, and more fuel-efficient vehicles today. Although leaded gas stuck around until the late 1990s, according to this year's EPA automotive trend report, "All vehicle types are at record high fuel economy and record low CO2 emissions in model year 2020," and that's true, despite a resounding shift away from the more fuel-efficient sedan and wagon segments and toward large trucks and SUVs with lower fuel economy and higher CO2 emissions.

The EPA has tested 4230 different 2021 model-year vehicles, including fully electric vehicles. Something to know: The big EPA fuel-economy numbers on the window stickers are estimates, driven by test data that simulates real-world driving. In fact, these ratings are mostly self-reported by automakers. Whoever performs the testing, be it the automakers or the EPA, that testing eliminates variables like temperature and traffic. Although these scientific methods are perfect for direct comparisons, the open road isn't as cut and dried as a sterile testing facility. We pit those simulations against real-world driving, using our own 200-mile highway loop on a stretch of Michigan's I-94. Our test cars maintain a GPS-verified 75 mph, utilizing cruise control as much as possible, with climate controls set to 72 degrees with the air conditioning on. In the past two years, more than 130 cars have surpassed their highway EPA estimates, with BMW (23), Mercedes-Benz and Mercedes-AMG (15), and Porsche (12) overachieving the most often. Here are the ones that beat the EPA by the most.

Jeep Gladiator: 35 Percent Decrease

We'll start with the biggest underachiever, our former long-term Jeep Gladiator Mojave. Buying an off-road vehicle for its highway fuel economy is like eating at Wing Stop to lose weight, but our Gladiator was off by 8 mpg. That's a lot. The EPA estimates a 23-mpg highway rating for Gladiators with the 3.6-liter V-6 and six-speed manual. We doubt very much the EPA estimated those numbers from a Mojave trim with 33-inch Falken WildPeak A/T tires and 4.10 axles. Early into what turned out to be an abbreviated 40,000-mile long-term test, our Gladiator Mojave returned just 15 mpg on the highway.

  • EPA Fuel Economy combined/city/highway: 19/16/23 mpg

  • C/D 75-mph highway fuel-economy results: 15 mpg

  • Model tested: 2020 Jeep Gladiator Mojave

SEE THE FULL GLADIATOR TEST HERE

2020 jeep gladiator mojave
Michael Simari - Car and Driver

Volvo S60: 24 Percent Increase

We've put Volvo's plug-in hybrid S60 to our 40,000-mile test and came away impressed by how well it drove and by how on several occasions it went farther than 450 miles on a single tank of gas—40 more than the EPA's estimate. Its complex 400-hp powertrain consists of a super- and turbocharged 2.0-liter inline-four and an electric motor. The EPA also estimates how far PHEVs can travel on electric power only, our S60 improved on that estimate from 22 to 25 miles. During our highway test, the S60 beat the EPA number by 8 mpg.

  • EPA Fuel Economy combined/city/highway: 30/28/33 mpg

  • C/D 75-mph highway fuel economy results: 41 mpg

  • Model tested: 2020 Volvo S60 T8 Inscription

SEE THE FULL S60 TEST HERE

2020 volvo s60 t8 phev
Marc Urbano - Car and Driver

Audi Q7: 29 Percent Increase

Audi refreshed its three-row SUV for 2020 with new styling and replaced the 333-hp supercharged V-6 with a more powerful turbocharged engine. The 335-hp turbo V-6 isn't a big leap in power, but it added 44 pound-feet of torque, resulting in a 1.0-second improvement in its now 5.0-second 60-mph acceleration time. So, the new engine energizing this Q7 is quicker and also a little thirstier, according to the EPA. The former supercharged engine was rated for 19 mpg in the city, 25 highway, and 21 combined, while the new turbocharged powertrain drops fuel economy to 17, 21, and 18 respectively. Despite the estimates, the Q7 achieved 27 mpg on our highway loop, beating its EPA value by 6 mpg.

  • EPA Fuel Economy combined/city/highway: 18/17/21 mpg

  • C/D 75-mph highway fuel economy results: 27 mpg

  • Model tested: 2020 Audi Q7 55 Premium Plus

SEE THE FULL Q7 TEST HERE

2020 audi q7
Audi

Audi A6 Allroad: 31 Percent Increase

We're big wagon advocates, even if they've been plasticized to inherit rugged looks like the Audi A6 Allroad. Skis, pool noodles, the family's 90-pound puppy, whatever, the wagonized A6 can handle it all. Under the bonnet sits a 335-hp 3.0-liter turbocharged V-6 bolted to a seven-speed automatic transmission. Designed as an elongated luxury sedan, the A6 achieved a spry 5.2-second lunge to 60 mph. During our highway fuel test, the A6 Allroad outperformed its EPA-estimated 26 mpg with a fantastic 34-mpg rating. That's a better highway rating than both the Mercedes-Benz E450 All-Terrain and Volvo V60 Cross Country we've tested.

  • EPA Fuel Economy combined/city/highway: 22/20/26 mpg

  • C/D 75-mph highway fuel economy results: 34 mpg

  • Model tested: 2020 Audi A6 Allroad

SEE THE FULL A6 ALLROAD TEST HERE

2020 audi a6 allroad
Marc Urbano - Car and Driver

Porsche 911 Turbo: 35 Percent Increase

An unlikely name-drop on the topic of fuel economy, the Porsche 911 Turbo beat its EPA-estimated highway fuel economy in our testing by 7 mpg. That same 911 Turbo S reached 60 mph in just 2.2 seconds, making it the third-quickest car we've ever tested. The cabriolet we tested was close behind, at 2.3 seconds to 60 mph. Power comes from a 640-hp 3.7-liter twin-turbocharged flat-six and an eight-speed dual-clutch automatic transmission. That raises another point: If you're beating EPA numbers in a 911 Turbo, you're actually losing.

  • EPA Fuel Economy combined/city/highway: 17/15/20 mpg

  • C/D 75-mph highway fuel economy results: 27 mpg

  • Model tested: 2021 Porsche 911 Turbo S

SEE THE FULL 911 TURBO TEST HERE

2021 porsche 911 turbo s
Michael Simari - Car and Driver

Genesis G70: 36 Percent Increase

We've referred to the quirky Genesis design language before as a mouth without a face, and if you look long enough at one you might become hypnotized by its isometric chrome. We don't feel bad picking on it, because the G70 is one of the best sports sedans sold today. The all-wheel-drive G70 3.3T we tested uses a 365-hp twin-turbo V-6 and eight-speed automatic transmission. It didn't just beat its highway EPA-estimate by 9 mpg in our testing, the most powerful version of the G70 also beat the most fuel-efficient G70 by 3 mpg on the highway. The rear-drive turbocharged four-cylinder G70 gets an EPA-estimated 31 mpg on the highway.

  • EPA Fuel Economy combined/city/highway: 20/17/25 mpg

  • C/D 75-mph highway fuel economy results: 34 mpg

  • Model tested: 2022 Genesis G70 3.3T AWD

SEE THE FULL G70 TEST HERE

2022 genesis g70
Andi Hedrick - Car and Driver

BMW X4 M Competition: 37 Percent Increase

Driving the BMW X4 M Competition as its engineers intended won't net atta boys from fuel-economy gatekeepers. Our observed fuel economy, found under what would best be described as real-world commuting driving, was a glacier-warming 15 mpg. What do you expect from a 503-hp 4500-pound SUV with a 60-mph time of just 3.3 seconds? Eco mode is a bad word in this rocket, but during highway testing the X4 M Competition behaved well enough to beat its EPA-estimate by 7 mpg while wearing Michelin Pilot Sport 4S tires. And that's certainly not the type of rubber associated with fuel economy.

  • EPA Fuel Economy combined/city/highway: 16/14/19 mpg

  • C/D 75-mph highway fuel economy results: 26 mpg

  • Model tested: 2020 BMW X4 M Competition

SEE THE FULL X5 M COMPETITION TEST HERE

2020 bmw x4 m competition
Michael Simari - Car and Driver

Porsche 911: 38 Percent Increase

Although not as wild as the 911 Turbo mentioned above, the less-rowdy Porsche 911 Carrera is still a party animal. The entry-level 911 has a 379-hp twin-turbo 3.0-liter flat-six and uses an eight-speed dual-clutch transmission. The slowest 911 sold today gets to 60 mph in 3.2 seconds and, if you ignore the Chevrolet Corvette, is still the best sports car for the buck. Something the base 911 and 490-hp 6.2-liter V-8 Corvette share is an EPA-estimated 24 mpg on the highway. Even with its touted cylinder-deactivation tech, the Corvette we tested was 1 mpg shy of that estimate, while the 911 beat it by 9 mpg.

  • EPA Fuel Economy combined/city/highway: 20/18/24 mpg

  • C/D 75-mph highway fuel economy results: 33 mpg

  • Model tested: 2020 Porsche 911 Carrera Automatic

SEE THE FULL 911 CARRERA TEST HERE

2020 porsche 911 carrera
Michael Simari - Car and Driver

BMW M3 Competition: 39 Percent Increase

The 503-hp BMW M3 Competition battled its Italian rival, the Alfa Romeo Giulia Quadrifoglio, through windy roads in Michigan as part of a recent comparison test. This is where the M3 belongs, darting between trees and the double-yellow line while its eager twin-turbo straight-six and eight-speed automatic answer every beck and call. The sad reality of driving, however, is that most commutes are plagued by boring roads and clogged with drowsy Honda CR-Vs. But on just such a straight highway, the M3 Competition is still a winner, beating its EPA-estimate by 9 mpg during our testing. The rear-drive model we tested was stuffed with nearly $20,000 in options but still outperformed its highway fuel estimates.

  • EPA Fuel Economy combined/city/highway: 19/16/23 mpg

  • C/D 75-mph highway fuel economy results: 32 mpg

  • Model tested: 2021 BMW M3 Competition Automatic

SEE THE FULL M3 COMPETITION TEST HERE

2021 bmw m3 competition
Michael Simari - Car and Driver

Bentley Flying Spur: 42 Percent Increase

The Bentley Flying Spur is a $223,925 answer to a 19 mpg question: What's it like to have too much? The 626-hp W-12 engine is legendary and capable of propelling this 5560-pound luxury barge to 60 mph in 3.5 seconds. It beats its EPA highway estimate by 8 mpg, although our 11 mpg observed paints a more perfect story of what it's like to be driven. Speaking of, the $6090 diamond-white paint job is just one of a few options on this $284,270 test car.

  • EPA Fuel Economy combined/city/highway: 15/12/19 mpg

  • C/D 75-mph highway fuel economy results: 27 mpg

  • Model tested: 2020 Bentley Flying Spur

SEE THE FULL FLYING SPUR TEST HERE

2020 bentley flying spur
Michael Simari - Car and Driver

Porsche Panamera: 43 Percent Increase

When shopping the most expensive Porsche Panamera sold today, don't let the mediocre EPA estimates for this 473-hp twin-turbo V-8 911 sedan put a dent in your TAG Heuer. The Panamera GTS is the übermacht of sports-sedan performance, achieving 1.02 g of lateral grip on our skidpad and getting to 60 mph in just 3.2 seconds, but its highway fuel economy deserves a mention too. It's no Taycan Turbo, but where range is considered, that's kind of a good thing. While the 2.4-second-to-60-mph Taycan 4S can go as far as 227 miles on a single charge, the Panamera GTS can go as far as 710 miles on a single tank of gas.

  • EPA Fuel Economy combined/city/highway: 17/15/21 mpg

  • C/D 75-mph highway fuel economy results: 30 mpg

  • Model tested: 2021 Porsche Panamera GTS

SEE THE FULL PANAMERA GTS TEST HERE

2021 porsche panamera gts
Michael Simari - Car and Driver

Every EV Ranked by Maximum Highway Range

evs with the most range 2022
Car and Driver

You Might Also Like