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Lotus Elise. (Lotus)
Lotus Elise. (Lotus)

Road Rush

When less is more Add to ...

Lotus designer Colin Chapman was the high priest of automotive weight reduction: It was rumoured that he designed cars by taking out one piece at a time until they collapsed under their own weight, then putting the last piece back in.

By the time of his death in 1982, Mr. Chapman was legendary for both his engineering genius and a willingness to push the limits - his cars broke so often that one driver suggested that every Lotus come with a free welding kit.

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Although he sometimes took things too far, Mr. Chapman was on to something.

Now, his weight-reduction mantra is becoming an article of modern faith. Fuel prices are on an upward arc, and tough new government regulations set efficiency standards that cannot be met without cutting vehicle weights across the board. Chapman founded the church of mass reduction. Now everyone is ready to worship.

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"Chapman was brilliant, no question," says Ruben Archilla, an engineer at Mazda's design headquarters in Irvine, Calif. "He understood vehicle dynamics. It's a simple equation. The more a car weighs, the more energy it takes to accelerate it and stop it. This is pure physics."

Archilla and his fellow engineers are scrutinizing every part for weight and function, and if a component can do two jobs, it does - an approach pioneered by Chapman back in the 1960s, when he made the engines of his Formula cars serve double duty as structural members that carried the rear suspension.

Today, every car company in the world has a renewed interest in mass reduction. Consider Porsche: Although the German manufacturer has always been known for high performance and light weight, the changing times have given mass even higher priority.

"Right now, weight reduction is everything," says Porsche Canada spokesman Laurance Yap. "When you take mass out of the car, everything gets better. The acceleration improves. The gas mileage improves. So do the braking and handling."

Last year, Porsche introduced the Spyder, a super-light version of its Boxster roadster. By eliminating luxuries like the electric convertible top, air conditioning and even the radio, Porsche cut the car's weight by 176 pounds, a loss of more than 6 per cent. Although the Spyder is a limited-production vehicle aimed at the purist driver, its philosophy has been applied to other Porsche vehicles, including the Cayenne SUV, the heaviest car in the company's lineup. Porsche designers carved more than 400 pounds out of the 2011 Cayenne compared to the previous model.

"It all adds up," says Yap. Porsche has studied the future of automotive design, and believes that weight loss will be an enduring theme: "Going forward, the mantra is intelligent performance," he says. "And there's no way to achieve that without mass reduction."

For more than a decade, North American car culture was defined by overweight luxury vehicles like the Cadillac Escalade - at 6,000 pounds, it weighs five times as much as Henry Ford's original Model T. But even sports cars have grown. The 1972 BMW Tii sports coupe weighed 2,200 pounds. Its modern successor, the sleek BMW M3, weighs 3,700. When the iconic Porsche 911 was introduced in 1964, it weighed about 2,000 pounds. The 2010 Turbo version weighs 3,400.

Other vehicles have followed a similar pattern - and there are reasons for the 70 per cent weight gains. Governments have enacted tough crash standards. Safety features like airbags, antilock brakes and stability-management systems add weight. But the biggest increases come from luxury and convenience features demanded by consumers - like air conditioning, power seats, electric sunroofs, automatic sunshades, power tailgates, video screens and 16-speaker stereo systems.

Smart engineering can cut the weight of a car. But real weight reduction also demands a different approach on the part of consumers. At Mazda, for example, Archilla and his colleagues believe that drivers are increasingly ready for small cars - like their new Mazda2 subcompact. With a weight of just 2,300 pounds, the Mazda 2 is part of a growing number of small vehicles offered to North American buyers - its competitors include the Toyota Yaris and the Honda Fit.

Archilla believes that rising fuel prices and a increased environmental awareness are making North Americans receptive to a new automotive paradigm. "First, you have to choose the right-size vehicle for the purpose," he says. "Some of this is already occurring, with the shift from SUVs to passenger cars. A lot of people have re-examined their needs."

Once they determine the minimum size for a vehicle, engineers focus on making it as light as possible. Mazda's approach to the 2 typifies current thinking. The body shell, for example, uses high-tensile steel in strategic areas - this allowed engineers to reduce weight while meeting tough crash test standards. Metallurgists studied every component in the car, from the engine to the transmission to the suspension arms, and specified tough, light alloys for the castings and forgings. By the time the car was ready for production, hundreds of pounds had been pared away, giving the Mazda2 sparkling performance with an engine that many North Americans would once have considered impossibly small - a 1.5-litre, 100-horsepower four cylinder.

"The engine is perfect for the car," says Archlla. "That's because we thought about weight all the time."

Archilla estimates that a 200-pound weight reduction translates into a fuel saving of about 5 per cent, all other things being equal. But the weight reduction also improves virtually every other aspect of the car, including handling. And one of the design team's inspirations came directly from Chapman - Mazda bought a Lotus Elise sports car to study its chassis design.

Few modern cars embody Chapman's mass reduction ethos better than the Elise. Although it's powered by a 1.8-litre Toyota engine, the Elise's extremely low weight enables it to accelerate as hard as many Ferraris - and go faster around a corner.

Although the Elise is too hard-core for the average driver (it has almost no sound insulation, and rides just a few inches off the ground) the car's phenomenal performance is a timeless reminder of what can be achieved through automotive weight loss.

"That car is a lot of fun," says Archilla. "It's amazing what it can do."

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