Chicago Automobile Trade Association

The struggle for automakers to solve car 'obesity' problem

June 8, 2012
Americans have a weight problem, with more than a third of us estimated to fall into the obese category. But it’s a problem automakers are struggling with too. Over the last several decades, the typical automobile has added hundreds of pounds, according to industry data, as it has grown longer and added more comfort, safety and convenience features.
Engineers are now struggling with how to cut all that added car flab. There are a variety of reasons why, but the biggest factor is fuel economy. The industry’s general rule of thumb is that 100 pounds equals one mile a gallon. And with automakers facing tough new fuel economy standards in 2016 and even more stringent mandates for 2025, it’s becoming critical to end the auto obesity epidemic.
The new Cadillac XTS underwent the automotive equivalent of liposuction. Though a full foot longer than the compact Caddy CTS, the 2013 Caddy sedan weighs about 100 pounds less, thanks to some creative engineering that includes the use of new, ultra-high-strength steel alloys.
Porsche was able to slash nearly as much weight off the new, seventh-generation 911 sports car through similarly creative engineering and the introduction of aluminum and even carbon fiber. The 2013 Boxster is expected to see similar mass reductions.
And though it’s slightly larger than the old model, the new Nissan Altima is 79 pounds lighter than the outgoing sedan. The process wasn’t easy, company engineers stress, and required an intensive focus on literally every element of the new Altima’s design, down to the re-engineered continuously-variable transmission. The new model also switched to lighter aluminum for its trunk, roof and hood.
Nissan will achieve a significant payoff (the base 2013 Altima is rated at 38 mpg on the highway) of as much as several mpg better than the so-called Eco versions of competitors, and without the added price premium.
“Cutting mass was a major factor in getting there,” along with improved aerodynamics and powertrain refinements, said John Curl, Nissan North America’s senior product planner for the Altima project.
It’s hard to find a manufacturer that isn’t putting a premium on cutting weight. Before retiring earlier this year, Ford product chief Derrick Kuzak laid out a goal of trimming as much as 750 pounds off the weight of Ford’s models.
But the process, which industry insiders have dubbed “lightweighting,” isn’t as simple as it might seem — especially in the United States, where people equate size with luxury.
The rule of the automotive business is that with every new model-year, “consumers expect more features and more and more safety equipment,” said General Motors designer Bob Boniface. Even that little CD changer built into the dash adds 5 pounds of mass, Boniface said.
Federal regulations further complicate the situation. Take the new roof crush safety standard that went into effect last year, effectively requiring manufacturers to more than double the ability of a vehicle to survive a rollover.
“You’ve got tough new safety standards that add weight at same time you have stringent new mileage standards,” complains analyst Jim Hall. “At some point, somebody’s going to have to blink.”
Perhaps, but Boniface and other industry leaders don’t expect to see regulators back off anytime soon. Instead, the pressure is on for the industry to come up with alternative solutions, whether through creative engineering or the use of breakthrough materials, such as carbon fiber.
The super-strong, ultra-light material has long been used in race cars and exotic automobiles, such as the $1 million McLaren F1 supercar of a decade back. But it is a major challenge to produce, requiring extensive labor that has priced it out of use by all but the most expensive automobiles. But that may soon change.
The original McLaren F1 used a carbon fiber “tub” that took 3,000 man hours to produce. On the next-generation Mercedes-McLaren SLR it still took 400. With McLaren’s newest street car, the MP4-12C, “believe it or not, we got it down to four hours on this car,” boasts chief designer Frank Stephenson.
That model is still beyond the reach of the typical motorist, at nearly $300,000. But carbon fiber will account for 44 percent of the material used in Chrysler’s reborn Viper sports car, at a quarter the price. And BMW believes it could soon bring the cost of the material down enough to use in models like the $40,000 3-Series. It will make extensive use of carbon fiber in its new BMW i3 and i8 battery cars because the lower weight will allow greater range.
The good news is that even the newest steel alloys are getting both stronger and lighter, helping to meet new safety mandates while also reducing mass.
But analyst Hall is skeptical that makers can pull several hundred pounds off the typical car, never mind 750, because of both federal rules and consumer demand.
“The best makers will be able to do,” Hall contends, “is manage the bloat.”
Designers like McLaren’s Stephenson and GM’s Boniface are more upbeat, though they admit it’s a challenge to deal with automotive obesity, much like it is for the mere mortal motorists who will have to squeeze inside their new automobiles.


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