2015 Mazda6 vs. 2015 Subaru Legacy

Can AWD be Fuel Efficient?


For decades, Subaru has been perfecting the craft of equipping all-wheel drive to nearly every product in its portfolio.

With so much experience and knowledge, the symmetrical all-wheel drive systems have been engineered into compact, lightweight units. Frequently beating its competitor’s all-wheel drive setups with better packaging and efficiency, Subaru has a new target in sight. It wants to offer all-wheel drive products with comparable efficiency to competitors with front-wheel drive powertrains.

SEE ALSO: 2014 Mazda6 Review – Video

During the new product launch for the new 2015 Legacy, Subaru kept commenting on how the permanent all-wheel drive sedan could match its front-wheel drive counterparts in real world efficiency testing. Wanting to evaluate this claim for myself, I decided to pit the Legacy against the 2015 Mazda6, another efficient mid-size sedan.

i-ELOOP vs. Symmetrical AWD

A few years ago Mazda switched from being the “Zoom Zoom” company to one that’s all about “SkyActiv.” Using a design philosophy that focuses on lightweight materials, friction reduction and efficient engines, the 2015 Mazda6 Grand Touring is rated at 26 MPG city and 38 MPG highway. Impressive figures already, add the energy recovering i-ELOOP system and the efficiency rises to a class leading 28 MPG city and 40 MPG highway.


The Subaru Legacy isn’t rated quite as high, with official figures pegged at 26 MPG city and 36 MPG. But remember, this is a car with permanent all-wheel drive. The Legacy sends 40 percent of its power to its rear wheels while still achieving EPA fuel economy ratings that beat those of the four-cylinder Toyota Camry. The Legacy 2.5i Premium I drove weighs 3,455 lbs., which makes it the lightest of the Legacy line-up. Svelte as that may make it seem, the Mazda6 still undercuts it by 223 pounds.


Driving for Maximum Efficiency

On paper the Legacy and Mazda6 match up fairly well. Both cars start at just over $22,000 after destination charges and use a 2.5-liter four-cylinder base engine; albeit with the cylinders sitting in different configurations. The power edge favors the Mazda with 184 HP and 185 lb-ft. of torque on tap compared to the Subaru’s 175 HP and 174 lb-ft.

Equipped with a continuously variable transmission, the Legacy has an aggressive throttle that makes smooth, efficient driving hard to achieve at first. With an initial lurch off the line, I found I needed to try to catch the engine between that initial forward jump and the point where it settles back down. The Mazda6’s six-speed automatic transmission provides a much smoother roll-out from a stop without peaks or valleys in the power delivery.


2,000 RPM is Enough, Thanks

In general, efficient driving requires you to pay more attention to the tachometer than the speedometer because it’s important to drive in the optimal RPM range. There’s a surprising amount of low-end torque in both cars considering their modest power output. Driving it slowly and smoothly, gear changes in the Mazda6 are quick and occur at just over 1,500 RPM. It’s also possible to keep the Legacy under 1,500 RPM with prudent throttle applications.

Only when climbing steeper freeway passages did I need to push either the Legacy or the Mazda6 past 2,000 RPM. With careful driving and planning, there was no reason to ever go beyond that point.

Compare Specs

2015 Mazda6
2015 Subaru Legacy
Vehicle 2015 Mazda6 Advantage 2015 Subaru Legacy
Engine 2.4L Four-Cylinder 2.5L Four-Cylinder
Horsepower 184 HP Mazda6 175 HP
Torque 185 lb-ft Mazda6 174 lb-ft
Transmission Six-speed automatic CVT
Curb weight 3,232 lbs. Mazda6 3,455 lbs.
Rear seat legroom 38.7 inches Mazda6 38.1 inches
Trunk space 14.8 cubic feet Legacy 15 cubic feet
Fuel economy (US) 28 MPG city, 40 MPG highway Mazda6 26 MPG city, 36 MPG highway
Fuel economy (CDN) 8.5 l/100 km city, 5.9 l/100 km highway Mazda6 9.0 l/100 km city, 6.5 L/100 km highway
Observed fuel economy 37.9 MPG Mazda6 36.8 MPG
Starting price (US) $22,010 $22,490
Starting price (CDN) $26,190 Legacy $25,090
Top trim price (US) $33,095 $33,380
Top trim price (CDN) $37,090 $36,990

Different Driving Styles, Surprising Results

By using the steering wheel mounted paddle shifter in the Mazda6, I achieved greater efficiency, especially when climbing hills, by forcing the car to stay in lower more efficient gears. At 50 MPH, you can keep the Mazda in sixth gear and maintain speed even on slight inclines.

SEE ALSO: 2015 Subaru Legacy Review

The Legacy calls for a different technique to achieve maximum efficiency. Instead of using the paddle shifters, I left the CVT in D (drive mode) and used various throttle applications to keep the engine speed low. In fact, at freeway speeds the Legacy would cruise at lower RPM in “D” than if slotted into the paddle-shifter-induced simulated sixth gear.

After several hours of driving, the Legacy was able to beats it’s official highway rating with an observed average of 36.8 MPG. Surprisingly, the Mazda6 wasn’t able to live up to the 40-MPG EPA figure, but it still beat the Legacy with an average of 37.9 MPG.


The Verdict:

Even if it came up short to the Mazda6, the Legacy can match most of its front-wheel drive competitors in terms of fuel efficiency while offering permanent all-wheel drive. The win still goes to the Mazda6 for being more efficient, having a more premium interior and for being more engaging to drive while sacrificing little ride comfort compared to the legacy.

Still, at least it’s good to know that if all-wheel drive is required in a mid-size sedan, it’s not only possible to get it in a wholly compelling package like the Legacy, but also one that doesn’t suffer the old drawback of excessive fuel consumption.

2015 Mazda6

2015 Subaru Legacy