Simanaitis Says

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TURBO FOOT?

THERE’S AN element of deception lurking in smaller turbocharged engines that are replacing larger normally aspirated engines. There’s also good solid logic—and even legitimate consumer choice—in this quest for enhanced fuel economy.

GuideCloseText

It’s all in the way you drive—and the way you read the advertising.

EPA fuel economy numbers are posted on new car Monroney stickers. These mpg values are based on highly reproducible lab testing, much more controlled than anything an ordinary driver might see in the real world. For more on these EPA fuel economy numbers, see www.wp.me/p2ETap-9s.

EPA

EPA Fuel Economy Guide 2013. Available from http://goo.gl//ctnB5.

Given something as inherently variable as driving styles, the instrumented EPA testing is as robust a metric as we can hope for. On the other hand, these clearly delineated City and Highway Cycles offer engineers an opportunity to optimize for the tests.

cycles

The EPA City and Highway test cycles are legitimate territory for engineering optimization.

There’s nothing deceitful in this; it’s sound engineering practice. An engineer can only guess about the real world, but the precise speeds, accelerations, pauses and power requirements are known for every instant of the test cycles. So why not optimize with respect to them.

But can’t this same gaming be played with normally aspirated engines as well as turbocharged ones?

Not as much. When the turbo is on boost, it’s forcing more air—and more fuel—into the combustion chamber for more power. The effect is more profound than any throttle action of a normally aspirated counterpart.

In a sense, the gaming of turbos has a better payoff.

However, the deceit—and, ultimately, consumer dissatisfaction—arises in the difference between the words “and” and “or.”

I suspect

I suspect this drifting Ford F-150 isn’t in the Eco portion of its EcoBoost.

“Hot Performance and High Economy!” should honestly read “Hot Performance or High Economy!” However, advertising copy doesn’t succeed on honesty; it’s assessed on effectiveness—as measured by sales.

Ford’s EcoBoost is a good case in point. About 80 percent of Ford’s North American products are available with this technology of engine downsizing, direct injection and turbocharging. According to Automotive News, June 10. 2013, Ford has sold more than 600,000 EcoBoost vehicles. More than 400,000 of these have been in one model, the F-150 pickup (which, month after month, year after year, scores as the country’s best-selling vehicle).

For a long time, V-8s have been the F-series’ popular powerplants. A “small” 5.0-liter V-8 was a choice of the mpg-frugal; only a wuss would opt for a six-cylinder.

Ford

Engine choices for the 2013 basic rear-drive F-150 are the 3.5-liter EcoBoost V-6 at left or the 6.2-liter normally aspirated V-8 at right.

For 2013, Ford rear-drive F-150s have two engine choices. Its 6.2-liter V-8 tests at 13, 18 mpg and 15 mpg, EPA City, Highway and Combined, respectively. By contrast, an EcoBoost 3.5-liter turbocharged V-6 gets 16, 22 and 18 mpg, City, Highway, Combined, respectively.

That is, in the controlled confines of lab testing, there’s only a 3-mpg difference in their EPA Combined estimates.

Thus, I’m not surprised to hear that some EcoBoost V-6 owners—namely those who exploit the Boost portion of the moniker—are seeing less fuel economy than owners of frugally driven V-8s. Those emphasizing the Eco part of the name—by not seeking boost at every opportunity—are likely coming close to EPA values.

Apart from the “and” suggested in advertising, there’s nothing deceitful. It’s simply—and logically—a consumer choice: How do you work that right foot of yours? ds

© Dennis Simanaitis, SimanaitisSays.com, 2013

One comment on “TURBO FOOT?

  1. William Rabel
    June 19, 2013

    Dennis –
    I wish you’d explore the ‘gaming’ of the EPA system, whereby many cars are morphing into crossovers (nee trucks) to give the manufacturers some sort of numbers advantage. The Volvo V70 is no longer available, leaving the V70XC, which sits higher. Ditto the Subaru wagon replaced by the Outback. The most glaring example is the new Porsche Cayenne GTS, where the US version sits a half-inch higher than the European version, lest it be reclassified as a car.

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