Join Date: Nov 2004
Turbocharged Cars Don’t Live Up to Fuel-Economy Hype Says Consumer Reports
Vehicle quality was not the only thing making news when Consumer Reports unveiled the results of its latest reliability study in Detroit earlier this week. Amongst the issues highlighted by the consumer publication were real world fuel economy and forced induction engine technology.
In particular, the watchdog organization took issue with downsized, turbocharged engines, citing efficiency and reliability issues with certain engines during real-world testing.
Currently, automakers are in a race to the bottom, slashing engine displacement and bolting on boost to help meet ever-stricter fuel-economy standards. Brands like Hyundai and Ford are seen to be leading the charge with turbocharged powerplants in mainstream products like the Sonata and Fusion.
“Engine downsizing is the biggest driver for turbocharging, along with direct fuel injection,” said Tom Grissom, Director of Business Development for BorgWarner Turbo Systems. He said they’re essential to giving smaller engines the performance characteristics drivers need.
BorgWarner sees big growth potential for turbos in North America. Grissom said, “the U.S. is fundamentally a gasoline-fueled passenger car market.” As automakers downsize engines they will have to turn to turbos. Europe’s vehicle fleet is already predominantly diesel powered, which means turbochargers are already on most engines there.
Bosch Mahle Turbo Systems, another major supplier of turbochargers to car manufacturers, projects that by 2019, 45 million turbochargers will be used in passenger vehicles annually.
LAB RESULTS, NOT THE REAL WORLD
Part of the discrepancy noted by Consumer Reports and documented anecdotally in AutoGuide reviews may come from the fact that so called “window sticker” fuel-economy numbers provided by the Environmental Protection Agency (EPA) are achieved through tests done in a lab, rather than on the street.
In the EPA test cycle vehicles are strapped to a chassis dynamometer, their drive wheels positioned on a series of rollers. The energy it takes to spin these rollers can be adjusted to simulate extra vehicle weight or wind resistance.
Once a vehicle is securely mounted on the dyno, a professional driver takes it through a series of simulated routes, accelerating and braking according to the standardized test schedule. Fuel economy ratings are determined by measuring the amount of carbon exhausted out the tailpipe. Obviously this methodology doesn’t work with electric vehicles.
Since 2008 the test has been amended to include additional variables, things like higher driving speeds, cold temperatures and air conditioning usage. These tweaks help the EPA test more accurately reflect real-world performance.
When contacted to see if new changes should be incorporated to close the gap between as-tested fuel economy and real world fuel economy on turbocharged cars, the EPA did not immediately respond. But given Hyundai and Kia’s recent trouble in this area, things may change in the future.
On paper the downsized-turbocharged formula really works to improve fuel economy. New-vehicle shoppers see bigger numbers on window stickers, but this is not something the folks at Consumer Reports found in their testing.
CHEVY CRUZE, FORD F-150 SINGLED OUT
Two examples cited are the Chevrolet Cruze compact car and the Ford F-150 pickup, both of which offer optional force-fed engines. Jake Fisher, the Director of Auto Testing at Consumer Reports said that even with downsized, turbocharged engines “[they deliver the] same fuel efficiency as their normally aspirated counterparts.” This calls into question the fuel-economy improvements automakers have made the last few years.
“EcoBoost had virtually the same zero to 60 time and 15 miles per gallon as the V8,” Fisher said of the F-150. This is not exactly a ringing endorsement of blowers and direct injection, given their added cost and complexity.
These engines have also proven to have reliability issues. According to Fisher, when it first came out, “the Mazda CX-7 turbo had a lot of problems… but they ended up working them out.” Also, “in previous years the WRX and other turbocharged Subarus were below average in reliability.”
Even premium brands have had some trouble in this area. Fisher said, “there were some early problems with BMW’s 3.0-liter turbo engine.”
Under-hood troubles can impact quality scores, but there are other factors to consider. Turbocharged powerplants are often found in higher-trim models. Typically these vehicles are delivered with extra options, which means there are more things to go wrong.
EPA standards are the law of the land so automakers follow them to the letter. As for the Chevy Cruze’s performance in Consumer Reports’ testing, Tom Read of GM Technology and Powertrain Communications said “based on their drive schedule they may have come up with something different from the EPA numbers.”
“The EPA numbers we report on are clearly better with the 1.4 turbo – 26/42 [miles per gallon] with the eco model versus 26/38 with the 1.8,” Read said.
Richard Truett, Powertrain Communications Manager at Ford echoed these sentiments. He said “a lot of it depends on how consumers use it” and “we’re discovering that people really enjoy the turbos.” In other words, buyers like the rush of acceleration they offer.
According to Truett, the 3.5-liter EcoBoost V6 offered in the F-150 can deliver superior fuel economy to the company’s the 5.0-liter V8 engine “if you use the turbos smartly.” He also said you can’t have your cake and eat it too; you have to keep a light foot on the throttle to maximize efficiency.
Lower-than-expected real-world MPG numbers don’t appear to be dissuading buyers from opting for boosted pickups. Truett said as of last month “EcoBoost alone is about 42 percent of F-150 sales,” adding “it’s exceeded all expectations of sales and performance.”
Summing things up, Read offered some advice, “no drive schedule can be perfect to simulate what a customer is going to get, but [EPA scores are] better than ever as an indicator of what a customer is going to get.” As always, you mileage will vary.