By on August 9, 2017

2017 Mazda 3 - Image: MazdaMazda 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.

Mazda 2017 EPA MPG Range Combined With Skyactiv-X 25% Improvement (MPG)  Class-Leading Competitor
Mazda 3
28-32 37-43 37 *
Mazda 6
28-30 37-40 52 **
Mazda MX-5 Miata
29 39 30 †
Mazda CX-3
29-31 39-42 31 ††
Mazda CX-5
26-27 35-36 34 °
Mazda CX-9
23-24 31-32 29 °°

* 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.

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

  • avatar

    Huh. I wonder if being SC by default will lead to any power gains. The 6 and CX-5 would benefit from that the most, I think.

    The CX-9 may not see this tech for awhile.

  • avatar

    The 6 and CX-9 would very much be on my radar the next time around if your estimates are close.

    Question: would the higher compression require 91 or higher octane (i.e. premium?)

    • 0 avatar

      Mazda managed to avoid that on the current SkyActiv-G engines despite their higher compression by specifying North American bound engines at a 13:1 ratio instead of 14:1 to allow for regular unleaded.

      I would be surprised if Mazda changes that philosophy for the NA market.

    • 0 avatar

      Considering that a compression ignition engine requires a high cetane number (and necessarily a low octane number) to function, I’d say no.

    • 0 avatar

      The 2018 mazda6 coming out in the spring will have 225hp and over 300 ft lbs of torque.

  • avatar

    More torque is always welcome my brothers.

    Let us see if Mazda shalt bring reliability to the altar of torque.

  • avatar

    While the fuel economy increase is great, I’m more interested in the ability of the supercharger to increase the power on something like a Mazda6 (generally underpowered). An extra 30% torque over the current offering puts it around 240 lb/feet, which is pretty reasonable for that car. Assuming some HP gains as well, that would make for a nice engine. Even if HP doesn’t change, the additional torque will certainly increase the “fun to drive” quotient (if my former TDI is anything to judge by).

  • avatar

    NVH Levels?????????

  • avatar

    They talked a good game on USA certified diesels too.
    Time will tell.
    Meanwhile, put an extra 25 bucks into corrosion resistance.

  • avatar

    To paraphrase Bob Lutz, “Only poor people care about fuel economy.”

    How much more POWER will these engines be making?

  • avatar

    I love how every Mazda article, no matter what the topic, will invariably have someone bring up NVH and rust, typically by people who have not driven current models, but not always. I can understand the NVH issue as being a deterrent. Mazda is quite capable of tacking the NVH issues, see current CX-9 as exhibit A. Why they don’t in the rest of their lineup, probably due to weight, but who knows.

    I was the owner, living in Detroit, of a 2001 Protégé5. I can attest to the NVH in that car, and rust on examples still in the road. But no issues with rust in the 5 years 100k miles I owned it. People who stick to stereotypes may just miss out on some things. Maybe a test drive before writing it off to NVH and rust lol. Whatever.

    • 0 avatar

      Regarding NVH they also fixed it in the new CX5. They are improving with each new model. More efficient and thorough than adding it one model year. So the 3 will get it next as the all new model us due next year. Then the 6.

      • 0 avatar

        I just drove my 2016 6 from Toronto to Chicago and back recently. It’s no S class for silence, but it was a huge step up from when I did it in the RX8, even though I put loud-ass Pierelli’s on the 6.

        the NVH is quiet enough at highway speeds in there that I didn’t even need to raise my voice to my passenger, which is about where the point of diminishing returns starts for me.

  • avatar

    With the improved torque and likely hp, I seriously wonder if the 2.5 will be relegated to top trims and the 2.0 will be the much more common engine across all vehicles but the CX-9. The skyactiveX 2.0 could probably produce power equivalent to the 2.5 as it is now. I am sort of waiting for this eventuality. If power is on par with rivals, I am sure there is temptation to downsize displacement rather than be the hp/torque leaders in every 4 cyl vehicle they make.

  • avatar

    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?

  • avatar

    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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