When the new Nissan Versa sedan rolls into showrooms, in the coming weeks, motorists might notice it’s a bit more svelte, despite adding decidedly more cargo and interior space.
The Japanese subcompact is 150 pounds lighter than the vehicle it replaces, reflecting a conscious effort to put the second-generation Versa on a diet. Indeed, Nissan has set a corporate goal of trimming at least 15% “off the weight of every vehicle” it develops, going forward, says Vice President of Product Planning Larry Dominique.
That’s a critical step in the maker’s efforts to meet consumer demands for better mileage – and rapidly increasing government fuel economy mandates. But it also underscores the conundrum makers like Infiniti face. Even as they use smarter designs and lighter materials to reduce mass, tougher regulations – particularly when it comes to vehicle safety – force engineers to add content that only packs the weight back on.
The industry continues to discover a variety of ways to improve fuel economy, notes Dominique, such as 8-speed gearboxes, advanced turbocharging and direct injection. But improvements to the internal combustion engine “are reaching their limits,” he stresses, “so we have to lighten up.
On a midsize car, goes conventional engineering wisdom, a 100-pound reduction can yield at least an extra mile a gallon. So on a 3,000 to 3,500 pound vehicle like a Nissan Maxima, a 15% drop would be substantial.
How to get there is the challenge. Makers like Nissan have been turning to lighter-weight materials, such as aluminum, magnesium and advanced plastics. And even when they use steel they’re switching, where possible to thinner, high-strength alloys. But “there’s a significant cost to that,” Dominique cautions. “I could make all my seat frames out of magnesium, but I couldn’t afford it.”
Automakers see carbon fiber as a sort of Holy Grail, as it is incredibly light and phenomenally strong. But, for now, it remains impossibly expensive, suited only to ultra-expensive models such as the Lexus LF-A supercar build by Nissan’s rival, Toyota. Like all so many other executives, Dominique says he is hoping that, going forward, new manufacturing processes will be developed to bring carbon fiber into the realm of mainstream automakers.
There are other ways to reduce weight, noted the Nissan planner. The new Versa has about 20% fewer parts and components. In some cases, developers were able to shift to one large piece of molded plastic where three might have been needed in the old sedan. And that reduces overlaps and eliminates fasteners that can yield a 5% savings, according to Dominique.
Meanwhile, by trimming the weight of the overall body, for example, Nissan might then be able to switch to smaller brakes and a lighter, less powerful engine. The new Versa migrates from a 1.8-liter inline-four to a new 1.6-liter engine.
The Japanese marque is by no means the only manufacturer pursuing significant weight reductions.
“In the mid-term, from now to 2017 or 2018, we’ll remove anywhere from 250 to 700 pounds depending on the vehicle,” said Derrick Kuzak, Ford’s global product development chief. (Click Here for more on Ford’s program.)
But such numbers can be misleading.
Nissan proposed weight reductions refer to apples-to-apples comparisons – that is, assuming that the next-generation Altima, for example, were to feature the same levels of content as the outgoing model. But that seldom happens.
For one thing, consumers continue to demand more and more content, whether it’s larger, more powerful infotainment systems or new, heated/cooled seats.
Add to that what the government continues mandating, such as the latest roof crush standards. “We know that keep adding weight to the car,” lamented Dominique, during an interview following a drive in the new Versa. “And that will offset much of the weight we hope to save.”