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Consumer Reports testing finds many small turbo engines underperforming; fuel economy, acceleration no better than in larger conventional powertrains

5 February 2013

Consumer Reports’ own fuel economy tests of vehicles equipped with small turbocharged engines has found in many cases that the turbocharged cars tested by CR have slower acceleration and no better fuel economy than the models with larger conventional engines, the organization said.

Consumer Reports tests many cars with small, turbocharged engines, and many competitors with traditional, naturally aspirated engines, large and small. Based on the EPA fuel-economy estimates, many of the charged engines look better. However, CR testers found those results don’t always map to real world driving and Consumer Reports’ own fuel economy tests.

As another example, in December, Consumer Reports road testing found the fuel economy on the 2013 Fusion Hybrid sedan and new C-Max Hybrid falling far short below Ford (and EPA) triple 47 mpg (5.0 l/100 km) figures—i.e., 47 mpg for city, highway and combined—for both vehicles. (Earlier post.)

While these engines may look better on paper with impressive EPA numbers, in reality they are often slower and less fuel efficient than larger four and six-cylinder engines.

—Jake Fisher, director of automotive testing for Consumer Reports

Consumer Reports points to the collection of 2013 Ford Fusions with EcoBoost engines as the latest example of underperforming small turbocharged engines. The smaller engine—a 1.6-liter producing 173 hp—is a $795 option over the basic conventional 2.5-liter Four on Fusion SE models. But that car’s 0-60 mph acceleration time trails competitive family sedans, and it delivers just 25 mpg, placing it among the worst of the crop of recently-redesigned family sedans, according to CR.

The most direct comparison among the vehicles Consumer Reports has tested is the Chevrolet Cruze. CR tested both a Cruze with the base 1.8-liter conventional four-cylinder, and one with the smaller 1.4-liter turbocharged four. While the 1.4-liter feels marginally more powerful in daily driving, it was barely faster to 60 mph, and got the same fuel economy as the larger engine, CR said.

The Hyundai Sonata Turbo, Kia Sportage Turbo, and Ford Escape 2.0T are examples of cars with turbocharged four-cylinder engines that are less fuel efficient than V6 models in the same class, Consumer Reports found.

Consumer Reports has also found some turbocharged four-cylinder models that do deliver good fuel economy and acceleration: BMW’s new 2.0-liter turbocharged four gets 28 mpg in the new 328i Sedan and delivered improved mileage in the 2012 X3 SUV by one mpg, with essentially identical power and acceleration.

Volkswagens using that company’s 2.0-liter turbo also return what CR calls “impressive mileage”, though CR hasn’t tested any model variations with other engines that are directly comparable.

In contrast, BMW's turbocharged four-cylinder engines seem to deliver both good fuel economy and acceleration: The 2.0-liter turbocharged four cylinder contributes to 28 mpg overall in our last tested 328i sedan. It improved mileage only marginally in the 2013 X3 SUV compared to the six-cylinder 2011 X3 we tested, with essentially identical power and acceleration but somewhat comprised refinement. The 2.0-liter turbo four cylinder engine we've tested in Audis and Volkswagens usually return impressive mileage, though we haven't tested any identical model powered by two different engines for such a direct comparison.

Consumer Reports testing results (turbos in bold)
Model Engine 0-60 mph EPA mpg CR mpg
Ford Fusion 1.6L Turbo 4 8.9 28 25
Hyundai Sonata 2.4L Four 8.2 26 27
Kia Optima 2.4L Four 8.6 27 25
Toyota Camry 2.4L Four 8.4 28 27 
Honda Accord 2.4L Four 7.7 30 30
Nissan Altima 2.4L Four 8.2 27 31
Ford Fusion 2.0L Turbo 4 7.4 26 22
Hyundai Sonata 2.0L Turbo 4 6.6 26 25
Kia Optima 2.0L Turbo 4 6.6 26 24
Toyota Camry 3.5L V6 6.4 25 26
Honda Accord 3.5L V6 6.3 25 26
Nissan Altima 3.5L V6 6.3 23 24
Chevrolet Cruze 1.4L Turbo 4 9.8 28 26
Chevrolet Cruze 1.8L Four 10.5 27 26
Dodge Dart 1.4L Turbo 4 8.6 31 29
Dodge Dart 2.0L Four 11.0 27 27
Ford Escape 1.6L Turbo 4 9.9 25 22
Honda CR-V 2.4L Four 9.2 25 23
Kia Sportage 2.4L Four 10.3 23 22
Toyota RAV4 2.5L Four (2012) 10.0 24 23
Ford Escape 2.0L Turbo 4 8.2 24 22
Kia Sportage 2.0L Turbo 4 7.1 22 21
Toyota RAV4 3.5L V6 (2012) 6.7 22 22
BMW X3 2.0L Turbo 4 7.3 24 23
BMW X3 3.0L Six 7.2 21 22
Ford F-150 3.5 V6 Turbo 7.7 17 15
Ford F-150 5.0L V8 7.8 16 15

February 5, 2013 in Engines, Fuel Efficiency | Permalink | Comments (23) | TrackBack (0)

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Comments

Is EPA playing a game to favor local products?
It seems that we are 'selectively' being taken for a ride.
In many cases the consumption obtained by CR is 10% to 20% higher than reported by EPA, specially on Ford and GM products?

OTOH, Honda's and Hyundai's products often did better?

Using CR figures, the average may be closer to 22 mpg than the reported 24.6 mpg?

In my experience (and opinion), Consumer Reports car testing biases tend toward the extreme, perhaps to produce more sensational press, so I tend to ignore them.

The Ford CR results consistently fall short.

ChristL...local independent testers have arrived to results very close to CR and not with EPA. They found an average of 20% difference with EPA, mainly on Big-3 units?

Hyundai admitted to reporting false MPG last year. They probably have an incentive to report accurate number snow.

My experience with Honda products is consistent with CR testing. Honda engines are very efficient at part load (e.g. highway cruising at constant speed). CRs highway mileage test is very simple: measure fuel flow directly at a steady 65mph. Some examples from this highway test:

'13 Civic LX: 47mpg (EPA 39mpg highway)
'13 Accord LX: 40mpg (EPA 36mpg highway)

I own a VW 1.8T and a VW 2.0T, and love them. But they appear to be very susceptible to individual driver habits. If I drive like an old lady, I get 15% better mileage than if I drive like a red-blooded American leadfoot. I suspect that the big 2.5L fours in Japanese mid size sedans are less variable, and that is what CR is observing.

OTOH, I looooooove spooling up the turbo.... so to hell with Consumer Reports.

I would not believe a word of what Consumer Reports has to say. They seem to have not no clue about statistics. In the past I have also seen different recommendations on car brand names that I know were built on the same assembly line by the same workers in random order. They are total idiots.

Stoichiometry is the big dog, and charging extra money for forced induction is the cat's meow.

That's the thing about turbos. You can get great mileage out of them if you take things easy. That way you are benefiting from lower pumping losses and lower friction losses (due to smaller displacement and higher torque at lower RPM).
That added efficiency goes out the window if you really lean on them, as CR testers probably do. No denying that turbo boost can be fun and addictive.

I drive a turbocharged mid-sized sedan, and my mileage numbers are slightly better than EPA numbers (3%). My highway numbers are way better than EPA (15%), but that's because the EPA test is a short loop starting from 0mph and involving several speed changes. That's easy to beat at a constant speed in a relatively slippery car.

Perhaps CR should try to "drive it like you own it," rather than "drive it like you stole it." It may cramp their test-pilot style, but it would better reflect consumers' actual lifestyles. I enjoy the odd full-throttle start, but 99% of my driving is in built-up areas where you really shouldn't go fast (pedestrians, kids, etc), and commuting where you can't go fast even if you try.

Is Ford 'polishing' the numbers? Their hybrids seem to suffer the same gap between real world fuel economy and EPA ratings.

Official test cycles are very precise loops intended to mimic the average driver, and the test are run on Dynos. The typical independent tester like CR jumps in a sees what happens. They drive like the motorheads they are. I can drive any car and do better or worse than EPA depending on what I do. The EPA tests are at best exactly similar tests that allow for the comparison of vehicles independent of driver variation. Nothing else. So having CR say anything about EPA numbers is ridiculous.

How can we assume that CR drivers would selectively drive a few trade marks differently than others?

My own pet theory ...

We want companies to build cars that are fuel efficient for a broad variety of driving styles so that they are good for a large section of the population. But as fuel economy becomes more important as a purchasing decision the companies will more strongly focus on improving for a particular driving style - the EPA one.

Perhaps the US brands are more optimized for the EPA than foreign brands. Explains observed results without any hidden agendas or secret bias.

Harvey,

Here's a different way of stating the same thing: a car with a V6 or a big 4 will always have poor fuel economy, no matter how you drive it. You can try driving slow, but you'll be using extra fuel because of the inefficiencies inherent in the design. Most non-turbo mass-market cars are really unpleasant to drive fast (noisy, no top-end power, jerky gear changes), so people won't bother. Ever try to drive a Camry in a lively way? There's really no point...

A smaller turbocharged engine can have very good fuel economy, or very poor economy, depending on how you drive it. The key difference is that turbo cars get more entertaining the more you rev the engine and the faster you go. The power just builds-up with the revs.

Most of us know that there's a time and a place for that kind of stuff. Automotive "test pilots" don't. That's why you read about stuff like "understeer at the limit," which is code for "nearly crashed." That's not the kind of stuff that regular drivers want to experience every day in cars that they own, with kids in the back.

It is still somewhat mysterious that many name brands claimed fuel consumption is very close to what people get and others are regularly 20% off?

Why the 20% (off) rule does not apply to all vehicles? Should EPA's testing be revisited again?

@Harvey: Most EPA testing is done by the car companies themselves with results submitted to EPA. The auto companies have a strong incentive to get good results, and are not unbiased testers. I would expect that the companies vary in how much they are willing to fudge the tests. One can imagine analyzing the test and tuning the ECU to the test to some degree. I have no specific knowledge about such things, but having worked in large corporations for many years, I can imagine just the sort of things that might go on, depending on the corporate culture involved.

Having an single, independent entity run the testing for all cars might give a more consistent picture, or help reveal flaws in the test methodology at any rate.

FWIW, I have found CR's mileage ratings to be on target.

@Nick

"One can imagine analyzing the test and tuning the ECU to the test to some degree"

Some manufacturers went so far as to put special code in the software to specifically detect the EU testing cycle and switch to a cleaner and/or more efficient program.

Yes NL... this type of self-testing-monitoring is probably as suggestive and biased as the self-testing-monitoring done by Tar Sands Developers and Operators to determine the pollution created by their current and future operations.

Most car specialists-testers will 'selectively' add 20% to EPA's and/or Big-3's claims.

Most Environmental Specialists will 'selectively' add 50+% to claimed-declared pollution from Tar Sands Operations.

Well protected (incorruptible) independent monitoring entities (if they still exist) should be called upon to overview the testing-monitoring done by manufacturers-operators and governmental agencies?

I can easily and consistently get 26 mpg over a tank of gas in the city when I drive at hours where I can match the timing of the traffic lights; one stop or almost stop every five miles. If I drive mildly but aim to keep my place in traffic during rush hour I get 8 mpg accelerating from the light and then slow and stop for the next light = ~16mpg.

What a (CR) driver gets while just driving around is like measuring how much the gas gauge drops in 10 miles and computing MPG.

The EPA sticker fuel economy is derived from a weighted average of 5 driving cycles: city, highway, city with cold start, US06 (more aggressive driving), and SC03 (hot ambient with air conditioner set for maximum cooling rate). In the recent past, auto companies had the option of just using the city and highway driving cycles and using a linear correlation to get "real world" driving numbers for the EPA sticker. EPA created the linear correlation to produce reasonably accurate estimates for 2008 vintage vehicles. I'm not sure if auto makers now have to use the 5 tests, or if they can still use the linear correlation with the city and highway tests. Detailed test result data is available at http://www.epa.gov/otaq/testdata.htm and for many of the cars there are only city and highway test results.

Given this background, there are several possible reasons why the EPA sticker numbers might not be accurate for turbos and for the Ford Fusion hybrid. Perhaps the weighted average of the 5 tests does not work very well for these vehicles. Or perhaps the linear correlation for the city and highway tests does not work very well for these vehicles. Of course, if drivers are much more aggressive in terms of acceleration and maximum speed, then their fuel economy will be worse than the EPA sticker would predict. Similarly, the Consumer Reports tests may or may not do a good job of predicting real world driving for these vehicles.

Might I suggest that the consumers of turbo vs non-turbo cars be different? Turbo drivers are much more likely to be aware of their driving style and utilize control to yield the experience they prefer. Non-turbo drivers are more likely to just drive in whatever way is more natural and convenient to them.

I also find it amusing that CR is ignoring the difference in cost of fuel per mile... some of the turbo-charged examples that get better mileage like VW and Audi require premium fuel to do so.
The cost of fuel per mile may actually be better in the 1.8T Cruze than the 2.0T BMW. CR doesn't point it out so I have to assume they didn't account for it.
I see this same failure when comparing the mileage of gas hybrids to diesels. Different fuels have different costs and energy content per volume so why would you directly compare their MPG ratings? Doing so is comparing apples to oranges.

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