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Ford EcoBoost vs. GM Active Fuel Management: Which is Better?

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2015 Silverado Engine lineup | EcoTec3 |V8 Engine Fuel Efficiency

GM’s famed 5.3-liter V8 EcoTec3 engine
© General Motors

In an effort to reduce pollution and reliance on gasoline, the Environmental Protection Agency (EPA) has been setting increasingly high goals for fuel economy that automakers are furiously working to meet.

Automaker fleets must achieve 54.5 mpg by 2025. This has led manufacturers to implement all sorts of tricks and tools to increase the fuel economy of their vehicles, which needs to improve at a rate of about 5% per year to meet the EPA’s target. Even Toyota has begun adding stop/start technology to its bigger vehicles.

And big vehicles are key. It’s easy enough to get good mileage out of small, lightweight cars, which is why big truck brands like Ford and GM have been focusing much of their efforts on their pickups. Performance cars have received attention too, as they tend to fall in the fuel-thirsty category.

What’s most interesting is how differently Ford and GM have approached the issue of raising fuel economy. While Ford is using turbochargers in its EcoBoost engines to make small engines produce big-engine power, GM is using Active Fuel Management cylinder deactivation to make its big EcoTec3 engines produce small-engine fuel economy.

Second-generation 3.5-liter EcoBoost engine 2017 Ford F-150

The 3.5-liter EcoBoost that powers the Ford F-150

In theory, Ford’s approach provides better horsepower and torque, allowing V6s to feel like V8s when pressing on the throttle while still getting V6-like fuel economy. However, this has the downside of adding complexity. Ford has recalled 170,000 Escapes because of quality glitches with its 1.6-liter EcoBoost and has also had issues with the EcoBoost-equipped F-150 pickup truck. In addition, when the turbocharger actually kicks in to give you that extra power, fuel economy goes down—as far down as in the single digits when pulling a trailer.

GM’s approach is completely different. Under light load conditions, its 4.3-liter V6 and 5.3- and 6.2-liter V8 EcoTec3 engines shut down two of their cylinders, turning the V6 into a V4 and the V8 into a V6. You still get all the power when you need it, but when you don’t, the engine focuses on economy instead—and GM has been tweaking the technology for so long that it happens so smoothly and seamlessly that the driver might not even notice.

The main advantage of the GM method is that it is far less complex than Ford’s, which makes it cheaper and more reliable. GM’s EcoTec3 engines also produce real-world fuel economy numbers that are closer to or even higher than their EPA estimates, whereas Ford EcoBoost engines usually miss the mark. Still, Active Cylinder Deactivation doesn’t solve the issue of low mileage when trailering.

Ultimately, the lightweight nature of Ford’s turbocharged engines help them get the edge when it comes to driving fun, but GM’s cylinder deactivation system takes over when it comes to real-world savings. No matter which approach is the “best,” both Ford and GM will have to continue improving their systems to meet the EPA’s increasingly stringent demands.

  • Gregory Faulkner

    Not so fast with your conclusions. Besides the fact that both of these technologies have been around a while and both are constantly being developed and improved and honed in; both are not mutually exclusive from one another, visa-a’-vis, GM Ecotec3s’ do not only employ only active fuel management and VVT, but also direct injection just like Ford Ecoboosts. So to state that Ecoboost is higher tech, is just not right. It should also be noted that GM uses the same sort of techniques (both DI & turbo charging) under this same name, Ecotec, in some of their cars. Additionally, I don’t think that either technology is all that complex in the whole scheme of automotive engineering (a.k.a. hybrids, electrics, and have you ever looked under the hood of a modern U.S. certified diesel). It’s just that, finally, the OEMs are starting to implement a little bit of more modern technology to the pickup truck segment that has been historically low tech. Also, the author failed to mention that GM has dealt with as many reliability issues concerning active fuel management, as Ford has with Ecoboost, even lately.

    So the big difference here is that GM has so far stayed with larger displacement and natural aspiration, because they believe that’s what their customers’ prefer, and they feel they can achieve what they want without downsizing displacement at least for now, and that turbos in this segment, at least for spark ignition, does not help enough to be worthwhile. Ford, on the other hand, believes turbo charging is a worthwhile technology for their trucks up to half-ton, and from a CAFE standpoint, they have moved up ahead of GM, and it is CAFE that really matters, as long as real world mpg is not behind the competition. The 2.7 liter, new for 2015, leads all gas-powered power trains in the segment starting at 19/26/22 versus GMs best rating at 18/24/21, city/highway/combined, respectively. And comparing the top-billed engines, it gets even more separated. Ford’s new-for-2017 3.5 liter comes in at 18/25/21 versus GM’s 15/21/18.

    As for real world, the media has beat Ford to death on this issue, but part of the issue is that Ford can’t help it if the average driver drives 80 mph on the interstate, and Ford can’t stop customers from adding outside accessories and modifications that kill mpg, such as brush guards, lift kits and leveling kits, which hurt all trucks, but hurt turbo charged gassers disporportionally. Ford is designing to a standard set by the EPA, and the EPA is setting a standard based on people driving within the law, driving like they care about mpg and leaving vehicles as they were designed.

    My 2015 Std Cab, 2WD, Short bed, with 3.31 gears and 2.7 liter Ecoboost has returned me almost 24 mpg life time. I easily meet the city rating of 19; probably better, and I can come close to the advertised 26 for round trip highway treks at 70 mph. So I know for a fact that Ecoboost works for saving fuel. My last NA V6 returned me 17 at best, and my last V8 returned me 16 at best driving just as conservatively as I do now. Ecotec3 may help that number some, but they also take alot of prodding to get them to go, as GM designs the trannys so that drivers give up on accelerating and just wait for the high gear to finally get them to speed, and the gearing ratios are like a rear drive car on those highest-rated versions, meaning more downshifts while cruising. So to get those good numbers, they employ more tricks that drivers are stuck with after delivery; they hurt refinement and driver satisfaction for the sake of mpg.

    And that brings me to my final point. When DI turbo gas motors are well designed, like Ford Ecoboosts, which are well proven and getting even better with each new engine, they provide great low end torque, decent acceleration without the need for downshifts, and so there is more to Ecoboost than just sportiness and good mpg, because even when taking it easy, it’s got that diesel-like quality that comes with good torque down low. And this is why many say you have to try harder to get better mpg with Ecoboost, because the GMs try to force one to drive like it’s in an mpg test, whereas one has to be easy on the F150 Ecoboost gas pedal to get the EPA effect, and so what’s wrong with taking it easy.

    But I agree that neither of these technologies will take them where they need to go for trucks, and that gas engine technologies have about peaked without some major breakthroughs such as HCCI, because both turbo charged gas engines and cylinder deactivated gas engines have only modest potential. They’ve also maxed out drive line, and and Ford has maxed out weight savings at this tow capability of over 10,000 pounds. One area of huge potential is drag reduction; another is electrification (at least partly); or diesel power, but breakthroughs are needed to simplify exhaust treatment systems, and make those components more reliable, more packable, less consumer intrusive, less service oriented, and cheaper to manufacture as well. At least though, Ford, GM, and Ram are doing something. Can’t make that case for the Japanese gas guzzler, low tech, NA V8 as the only choice from them and full size trucks.

    • nam

      Excellent points ! Almost every review beats on the Ecoboosts for poor fuel economy. But I get very close to the posted EPA numbers with my 2.7 EB and it is a blast to drive if I choose to drive it that way. And the low end torque really is magnificent. With the price of diesel now , it would take me more years to break even with the Ram Ecodiesel than I would ever own the truck . And GM has really taken the pleasure out of driving altogether. The 2.7 EB really is the sweet spot for most pick up drivers who rarely tow and still want good fuel economy and torque without the extra expense of a diesel