This Is What Mazda EPA MPG Results Will Look Like With Skyactiv-X HCCI Engines (Asterisk, Fine Print, Subject To Change)

Timothy Cain
by Timothy Cain

Mazda announced on August 8th what had long been rumored. The small Japanese automaker has successfully overcome the remaining issues which held at bay mass production of gasoline compression ignition.

Essentially, Mazda’s Skyactiv-X engines, due first in the next-generation 2019 Mazda 3, is intended to bring diesel-like ignition to small, supercharged four-cylinder engines, along with diesel-like fuel economy. However, the gas-fired Skyactiv-X engines will be wildly cleaner than diesel powerplants. Mazda has said in the past that these HCCI engines will likely limit the need for continuously variable transmissions. We also learned, with Mazda’s latest pronouncement, that the company’s Skyactiv-X engines will be significantly torquier than their Skyactiv-G predecessors.

If Mazda can live up to its pronouncements — the company says the engines are “still under development and figures are subject to change” — it’ll be a win for both the environment and driving enthusiasts. And because Mazda also claims a 20-30-percent improvement in fuel efficiency, it’ll be a win for your bank account, as well.

We wanted to see exactly where Mazda’s alleged fuel savings will put Mazda’s current products on the EPA’s miles per gallon scale, so here are the results of some quick math.

One column below shows the fuel economy ranges of Mazda’s current six-model U.S. lineup. We’ve opted to show the combined figures only to avoid cluttering with too great a quantity of numbers. Another column shows the same Mazda products with a 25-percent (the average of Mazda’s claims) reduction in fuel consumption. An extra column shows where current class leaders are positioned.

Naturally, rival automakers have just as much license as Mazda to make fuel efficiency advances over the next two or three years, so don’t assume the figures in the competitors’ column will hold through 2017.

Mazda2017 EPA MPG Range CombinedWith Skyactiv-X 25% Improvement (MPG) Class-Leading CompetitorMazda 328-3237-4337 *Mazda 628-3037-4052 **Mazda MX-5 Miata293930 †Mazda CX-329-3139-4231 ††Mazda CX-526-2735-3634 °Mazda CX-923-2431-3229 °°

* Presently, the Mazda 3 rival with the greatest combined mpg is the Chevrolet Cruze Diesel, rated at 37 miles per gallon combined. The Hyundai Elantra Eco has a combined rating of 35 mpg, as does the Honda Civic with a 1.5-liter turbo.

** The 2018 Toyota Camry Hybrid LE is rated at 52 miles per gallon combined. The most efficient non-hybrid midsize sedan is the base Camry at 34 miles per gallon.

† The Fiat 124 Spider, incidentally a Miata-based car, has an EPA combined rating of 30 mpg.

†† The front-wheel-drive Honda HR-V is rated at 31 mpg combined.

° The front-wheel-drive Nissan Rogue Hybrid is rated at 34 miles per gallon combined. Among non-hybrid compact crossovers, the FWD Honda CR-V 1.5T is the leader at 30 mpg.

°° The Toyota Highlander Hybrid is rated at 29 miles per gallon. The front-wheel-drive Kia Sorento 2.4 is rated at 24 mpg combined; the FWD non-hybrid Toyota Highlander at 23.

[Image: Mazda]

Timothy Cain is a contributing analyst at The Truth About Cars and and the founder and former editor of Follow on Twitter @timcaincars.

Timothy Cain
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  • Tstag Tstag on Aug 09, 2017

    It's pretty amazing how the worlds automakers continue to pour billions into ICE and gearbox development whilst knowing that the electric car is getting closer to the mainstream all the time. There must be a real opportunity for a company like Cosworth with a pure focus on engine development to step up and roll out new types of engine on an almost annual basis if the worlds automakers decided to centralise more investment with a company like them. Think of all of the recent advances we've seen from cylinder shut down capability to this. If a company like Cosworth focused on engine design it could outsource the part manufacturing to regional hubs and then get car companies to use existing facilities to do assembly. It's the way chip maker ARM operate so why not the car industry?

  • Luke42 Luke42 on Aug 10, 2017

    Mazda is still fighting the last war. Our next car purchase will be a Tesla Model 3, not a Mazda 3. Our Mazda 5 might last long enough to be replaced by a Tesla Model Y. If it doesn't last long enough, we will replace it with an Odyssey which had Honda Sensing. Honda has them beat as a value purchase, and also as a cheap cheerful car which handles well (especially in the Civic w/ Honda Sensing vs the 3). I want to root for Mazda, because our Mazda 5 is a 90s car done right. But Mazda's lineup is already obsolete, and it's going to be much more so driving assistance technology and electrification hit the mainstream when the Model 3 deliveries begin in earnest. Between the Model 3 and the Civic, I just don't see Mazda lasting in their niche -- unless their crossovers start to sell in extra-amazing numbers...

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  • Rover Sig We have a car with two fake exhausts in the bumper, but a large shiny muffler visible hanging down on one side, not aligned with the fake exhaust exits. Horrendous. I had to paint the shiny muffler with high-temp black paint to make it less visible. Exhaust pipes were meant to be round and hang below the bumper, and they can be made quiet or loud as the engineers like. But fake exhausts rank down there with fake intake vents on the side of that old Buick.
  • EBFlex Of course it does. What a silly question
  • Buickman Elon is a phony.