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We have seen (and driven) the future of the sports car, and it is the All-Star winning BMW i8. The halo car for BMW’s Project i melds the brand’s sporty dynamics and premium refinement with plug-in-hybrid efficiency.
Carbon-fiber-reinforced plastic (CFRP), more commonly known as carbon fiber, is key. Used in Formula 1 since the early 1980s, the strong, lightweight material makes it possible to combine sporty dynamics and premium refinement with dramatically reduced carbon-dioxide emissions. Partner SGL Group of Wiesbaden, Germany, makes the material for the body shells of the i3 and i8 at its carbon-fiber plant in Moses Lake, Washington. In the coming years, BMW’s Project i will add a range of models between those numbers, project chief Ulrich Kranz says.
“CFRP is about 30 percent lighter than aluminum and 50 percent lighter than steel. Used in the right places, this material reduces weight, optimizes the vehicle’s center of gravity, and improves body strength.”
“Lightweight design is a key technology in the quest for reduced fuel consumption and CO2 emissions,” Kranz tells us. “Lightweight
design is also particularly critical in the BMW i3 because of its key role in determining what size of battery will be required and what mileage range can be achieved. It is the combination of SGL’s advanced carbon fibers and BMW’s unrivaled know-how in mass production of the CFRP components that will allow us to produce carbon-fiber components at competitive costs to alternative materials.”
The cost of carbon fiber is partially offset by the benefits of its low mass, which allows Project i to downsize “very expensive” battery systems, Kranz adds.
“For the same function, CFRP is about 30 percent lighter than aluminum and 50 percent lighter than steel. Used in the right places, this material reduces weight, optimizes the vehicle’s center of gravity, and improves body strength.”
About half the BMW i3s sold to date (both globally and in the U.S.) have the optional range-extending 0.6-liter two-cylinder gas engine, Kranz reports. So equipped, the 3,130-pound i3 has a 117 mpge/39 mpg (gas only) combined rating and a 150-mile total range (81 miles for the EV-only model), and it’s 122 pounds lighter than the electric-only Honda Fit EV. Meanwhile, the electric-only BMW i3 weighs 2,860 pounds.
But it’s the sleek, sinewy 3,455-pound BMW i8 that exemplifies the Munich brand’s dynamic automotive artwork. Powered by the Mini Cooper’s turbocharged three-cylinder engine, pumped up to 228 hp and 236 lb-ft, and a 129-hp synchronous electric motor, this 2+2 coupe gets to 60 mph in 4.2 seconds and reaches a top speed of 155 mph. At the same time, BMW’s exotic sports car has an EPA fuel-economy rating of 76 mpge/28 mpg (gas only) combined and delivers a cruising range of 330 miles.
When the BMW i project began, CEO Norbert Reithofer paid up front for BMW’s 50/50 investment in the Moses Lake plant to keep Project i unburdened by the fixed capital costs. “If everything continues to go according to plan, we will earn a reasonable margin per vehicle and make money on every car,” Kranz says about the investment. “We don’t build vehicles that are not profitable.” This is quite a statement when you consider that the BMW i3 starts at $42,300 before any tax incentives.
‘Unrivaled know-how:’ BMW has mastered mass production of carbon-fiber-reinforced plastic components, allowing for lightweight body shells of the i3 and i8.
Moses Lake was also chosen for its ability to meet an acceptable standard of sustainability. Carbon-fiber production is energy-intensive, and the factory gets its electricity from a hydroelectric dam on the nearby Columbia River. BMW and SGL developed shorter production times and lowered baking temperatures to produce the carbon fiber, though they won’t detail how they achieved these cost-reducing methods.
The joint venture already has doubled Moses Lake’s initial annual production of carbon fiber to 6,000 tons and is in the process of increasing it again to 9,000 tons per year. BMW plans to produce 27,500 units of the i3 and 10,000 units of the i8 in 2015, and will add an i5 model shortly after.
BMW believes the cost of carbon fiber could ultimately drop by 90 percent, well within the ballpark of steel. Aluminum may be the new lightweight miracle material for full-size pickups, but for cars—and especially sports cars—carbon fiber is the future.
Read about the 2015 AUTOMOBILE All-Stars: