The light rider

HOW DO YOU CREATE A monster? Take a tough, lightweight, aluminium frame and wrap it around a 5 litre V-8 generator that cranks out 385 horses. With 98% of its body made of lightweight materials, that’s what Jaguar Land Rover’s third generation XJ is all about. Even though lowering emissions, using recycled materials, and getting better fuel economy drove that design, the result is a body shell weighing as much as a Mini Cooper.

“As much as 50% of the aluminium alloy in the XJ’s structure is from recycled material, and the way it’s put together means no cooling water is used, and power consumption is low because we cut back on welding,” says Mark White, Jaguar Land Rover’s chief technical specialist. Jaguar’s XJ and XK sedans use patented epoxy and riveted bonding that make the body shell more rigid than those that are welded.

That makes a Jaguar XJ’s body shell weigh about 300 kg—less than a Mercedes S-Class, or a BMW 7 Series, or an all-steel Jaguar whose shell weighs over 500 kg. In development for about 10 years, JLR’s lightweight technology began by costing the company twice that of a steel body shell. “That’s now down to about 25%,” White says. “The technology has to be invisible to customers and they shouldn’t realise they’re driving a lightweight car.”

The fuel-saving design is already in use in Jaguar’s XK and, in Land Rover vehicles such as the Range Rover Evoque that will hit the road in Europe in 2012. “Our technology will include aluminium, magnesium, lightweight thermoplastics as well as high-strength steels to get weight savings of over 80 kg,” White says.

The big question: Can such technology make its way to mass-volume passenger cars like Tata Motors SUVs? “Lightweighting is limited for lower-cost vehicles,” says Wilfried Aulbur, partner with strategy consulting firm Roland Berger and former CEO of Mercedes-Benz India. “In the luxury segment, certainly, there’s a significant amount of pressure to slash fuel consumption for everyone.”