2013 Honda Accord vs. 2014 Mazda 6 vs. 2013 Nissan Altima Comparison Test

Thirty-nine point-seven. As in 39.7 mpg.

That's what the 2013 Nissan Altima 2.5 SV averaged over the course of our 116-mile Edmunds test loop, a route that includes slogging through downtown Santa Monica, ocean-view cruising on Pacific Coast Highway, semi-spirited running on Mulholland Drive and a steady 70 mph drone on Highway 101.

But it's not just the Altima's 39.7 mpg number that's remarkable. What stands out even more is that the 2014 Mazda 6i Grand Touring and 2013 Honda Accord EX-L Navi averaged 5.1 and 5.4 mpg less, respectively, over the exact same route, on the same day, at exactly the same time, driven in exactly the same fashion. That, fuel-sipping friends, is big-time mileage.

But it takes more than an mpg spanking to win an Edmunds midsize four-cylinder sedan test.

Let's find out what it does take.

Fresh Faces
We chose the Accord, Mazda 6 and Altima because they're the freshest designs in the segment and, with four cylinders and automatic transmissions — continuously variable transmissions (CVTs) in the case of the Accord and Altima — they're representative of the cars Americans buy.

The Accord EX-L Navi and Mazda 6i Grand Touring represent the top four-cylinder trim levels available, while the Altima 2.5 SV Nissan supplied us with is one rung down from the top SL. As such, the Nissan Altima 2.5 SV came in the cheapest at $27,005, even with its $1,350 Convenience package (one-touch auto up/down windows, sunroof, foglights). It's got just about all the goodies the other two have, including push-button start, navigation, rear A/C vents, rearview camera, a USB port and Bluetooth. But the Altima does without the latest active safety systems such as lane departure warning and active cruise control.

The $30,785 2013 Honda Accord EX-L Navi comes fully stocked with, yes, navigation (hence the name), leather seats as opposed to the Altima's cloth and a 360-watt stereo system, which makes the best sounds of the bunch. It also comes standard with forward collision and lane departure warning systems.

The brand-spanking-newest of the group, the 2014 Mazda 6i Grand Touring, was also the most expensive at $31,190. It sported leather seats (heated up front), TomTom navigation and a rearview camera, as well as blind-spot monitoring, rear cross-traffic alert and optional radar cruise control ($900).

Four-Cylinders Are the New Normal
Admit it. You're still pondering the Altima's fuel mileage. It baffled us, too. So how does it do it? Well, it's not through direct injection, as it's the only one of the three to still use old-school multiport fuel injection. Regardless of fuel delivery, the power outputs from this trio of four-cylinder engines are nearly identical.

The Altima's 2.5-liter puts out 182 horsepower and 180 pound-feet of torque. The Accord's 2.4-liter makes 185 hp and 181 lb-ft. And the Mazda 6's 2.5-liter manages 184 hp and 185 lb-ft. There's not a thrashy one in the bunch, but the Mazda 6 was the loudest at wide-open throttle (73.8 decibels) and the Altima the quietest (70.7).

They differ in the way they transfer power to the front wheels, however. The Accord and Altima use CVTs while the Mazda 6 uses a traditional six-speed automatic, replete with paddle shifters and rev-matched downshifting.

Still, with such similar power levels, it comes as no shock that none of the three distinguished itself at the test track. The two CVT-equipped cars seemed initially baffled by a full-throttle launch, but once underway they quickly pinned the revs and held them through the quarter-mile on the way to 60 mph in 7.8 seconds for the Accord and 7.9 seconds for the Altima. The Mazda 6, on the other hand, was willing to spin the front tires, helping it get to 60 in just 7.6 seconds. (7.3 seconds with a 1-foot rollout as on a drag strip).

The 2014 Mazda 6 remained quickest through the quarter-mile at 15.7 seconds versus the Accord's 15.8 and the Altima's 15.9. But by this time the Mazda's launch meant little, the Accord achieving a higher trap speed of 89.6 mph against the Mazda's 88.1 and the Altima's 87.7.

An Automatic for the Enthusiast People
The Mazda's six-speed is an excellent example of a true automatic. It offers smooth yet quick shifts, and it's not overly busy on long uphill grades. Plus it can be shifted manually via steering wheel paddles or the console lever and will hold gears right up to its redline. In Drive mode, however, the Mazda's gearbox is not as quick to react as the Altima's CVT.

And that CVT is key to the Altima's miserliness. One of its fuel-saving tricks is its constant attempts to drop the revs as low as possible as soon as possible, to the point that it often feels like it's lugging the engine. But Nissan's engineers also made this CVT highly responsive, so as soon as you dip into the throttle for a tad more power, it responds immediately. The downside is sometimes we don't want 5,000 rpm worth of CVT fury to get just a bit more acceleration.

The Accord's CVT, on the other hand, could easily be mistaken for a regular automatic. It's neither as "luggy" nor as responsive as the Altima, and therefore it's a wholeheartedly calmer experience. In short, it's the CVT for people who don't like CVTs.

At 3,170 pounds, the 2013 Nissan Altima is the most feathery of the group by 117 pounds over the Mazda 6 and 187 pounds over the Accord. This no doubt helped its fuel economy numbers, which paid off not only on our test route. The Altima managed 31.7 mpg over its entire stay with us, while the Mazda 6 averaged 27.1 and the Accord just 26.8 mpg.

Comparing the Cabins
It's fun to throw around acceleration and fuel economy numbers, but they mean little if a sedan can't fulfill its needs as basic, everyday transportation.

So let's start with the completely bewildering: the Mazda 6. Here's a car slathered with a complete redesign, yet its center stack is stale while its tiny, 5.8-inch TomTom navigation screen already looks dated. Other oddities include front door pockets only large enough for one water bottle, and air-conditioning vents that are positioned too low in the dashboard.

On the plus side, the Mazda 6 has snazzy and easy-to-read instruments, and the utter simplicity of the HVAC controls makes them easy to use. We also like the lateral support provided by the Mazda's seats.

Hop in the Accord and things look clearer. Particularly the superb 8-inch navigation screen, easily the largest and sharpest of the group (although it's also situated the farthest away). There's a pleasing mix of large buttons and knobs, and the controls exude the damped, quality feel we love.

Some editors found the smaller secondary screen an oddity, while others thought the tachometer was too small. The front seats are flat and wide and lack the lateral support found in the Mazda. The cushions get surprisingly uncomfortable after a couple hours of seat time, and the center and door armrests are woefully under padded.

The Altima splits the difference between the Accord and the Mazda 6 in terms of both style and utility. Its 7-inch nav screen is big enough to use easily, the controls are intuitive and while its center stack presentation isn't the most stylish, it just flat works. The tach-speedo combo is by far the largest and easiest to read quickly, and without question its cloth-covered seats are the most comfortable.

That said, the center and door armrest coverings feel cheap and we question their durability, though the Altima's center armrest bin gets points as the most cavernous. As far as ease-of-use, we set an all-time Edmunds speed record for pairing our iPhone.

Take a Backseat
If you took a glance at the Mazda 6's sexily aggressive roof line and guessed rear passengers would pay a price, you'd be wrong. Other than a slightly more difficult entry in the 6, headroom was similar for all three sedans, enough to fit a 6-foot, 2-inch adult. The Mazda's shorter side and rear windows make things more claustrophobic, and the Accord and Altima both have better elbow room.

It's a dead heat between the Accord and Altima for trunk capacity, the former at 15.5 cubic feet and the latter at 15.4. The Mazda's is the smallest at 14.8, but it's also the most uniformly shaped. Our own measurements showed the Altima had the lowest cargo loading height, the widest opening and the most width between the wheelwells, while the Accord was the worst in this category.

The 6 wins for overall utility, its split-folding rear seats lying down almost flat with by far the most generous trunk pass-through. The Altima's seats weren't quite as flat-folding, and its pass-through a bit tighter. Meanwhile, the Accord's one-piece folding rear seat and miniscule pass-through seem more to satisfy a spec sheet than provide any real convenience.

What Can They Handle?
Even the most conscientious of us are late sometimes, so it doesn't hurt if your family sedan can handle a little giddyup. At our test track we found all three cars turned in similar, if mediocre, numbers. But they went about the task in very different ways.

The Mazda 6 easily felt the sportiest through the slalom, with the most precise steering and fluid handling. It would've easily notched a better number than 63.0 mph if not for the most intrusive stability control system of the group.

The Accord has quick initial turn-in, but the chassis allows lots of body roll, limiting it to 63.5 mph. The Altima benefited from the least intrusive stability system, and even with over-boosted steering, it garnered the fastest time at 63.8 mph.

Out on public roads, where you almost never invoke a stability control system, the Mazda 6 is in another world. And a fine world it is. The suspension feels properly snubbed down, yet there's plenty of damping for bumps. The precise steering makes it a joy to flick through corners. In contrast, the floppier, loose-steering Accord is more a chore than a pleasure in this setting. The Altima strikes a nice balance between the two, not as tied down as the 6 but with steering that offers significantly more feedback than the Accord.

And the Mazda 6's shiftable automatic offers levels more driver control than the two CVTs on back roads.

When simply cruising along, the Altima offered the comfiest ride and the least road noise (62.2 dB at 70 mph). The Accord rode more firmly than its so-so handling would lead you to believe, and had the most road noise. The Mazda's oversized 19-inch wheels endowed it with the most jittery ride.

The New Champ
Although the 2013 Honda Accord topped the Toyota Camry in our last comparison, in this test the Accord just couldn't quite keep pace with the Altima. Its ride comfort, storage options, seat comfort and cargo flexibility are all a step behind the Nissan's. The Accord's excellent build quality, first-rate controls and superb nav screen just can't overcome these other foibles, and while there's nothing offensive about the Accord's driving demeanor, it's simply not as fun as the Altima or Mazda 6.

Now if you like driving simply for the sake of driving, the 2014 Mazda 6i Grand Touring is a standout choice. It's unquestionably the enthusiast choice here, and makes no bones about it with its aggressive 19-inch wheels and tires. This is the only one of the three that makes sweeper on-ramps worth attacking. It's the only one we'd hand wash just to fondle its fenders. But while its exterior is gorgeous, the interior is far less impressive.

That leaves the 2013 Nissan Altima 2.5 SV. Our winner is good at nearly everything, with only minor deficiencies. It drives well, has comfortable seats and remains quiet on the highway. It's no Mazda 6 in terms of handling, but it's at least somewhat entertaining on a twisty road. And even though it was the least expensive car here, it rarely felt like it.

The mileage figures only add to the Nissan's appeal. Delivering almost 5 mpg more than the Accord and Mazda 6 on our test loop was no small feat. Then it followed it up by surpassing the EPA's combined mileage rating in city and highway driving. That's a rare feat in any type of car. Sure, you could find a hybrid sedan that's more efficient, but none of them put together the complete package as well as the Nissan Altima.

The manufacturers provided Edmunds with the Mazda 6 and Nissan Altima for the purposes of evaluation. The Honda Accord was purchased by Edmunds.