A 42mpg Diesel Roadster- fun as it is efficient

Diesels are fuel efficient and practical, but they're dogged by a reputation for being about as much fun as a tax audit. VW's worked hard to change that perception with cars like the Jetta TDI, but it might be the sweet Concept BlueSport roadster that finally convinces Americans diesels are cool.

The mid-engined sports car made its world debut at the Detroit auto show, and although it's just a concept, there's no reason why VW couldn't - or shouldn't - build it. The car gets 42 mpg and emits about as much CO2 as a Toyota Prius, and it is emissions-legal in all 50 states so even car-crazy Californians could buy one.

BlueSport relies upon three technologies VW believes will become more prevalent as the auto industry develops cleaner, more fuel-efficient cars: turbocharging, automatic start-stop technology and regenerative braking. "The future of Volkswagen belongs to cars like this," company chairman Martin Winkerhorn said as he unveiled the car, which could appear in showrooms in 2011.

We sure hope so.

Volkswagen has been toying with the idea of a two-seat, mid-engined sports car since unveiling the Concept R in 2003. It rolled out another one, the EcoRacer, two years later at the Tokyo auto show. Such a car always seemed like a long shot, though given it would compete with the Audi TT and perhaps the Porsche Boxster. But VW keeps teasing us, and along comes the BlueSport, built with off-the-shelf parts to keep costs down - and raise our hopes that production might be financially feasible.

VW started with an aluminum chassis and body to minimize weight, then shaved more weight with an aluminum manual folding top, lightweight leather seats with one-piece backs and other tricks. As a result, the 13-foot-long car weighs just 2,640 pounds, making it about the same size and weight as a Honda Fit.

Propulsion comes from a 2.0-liter turbocharged common-rail TDI clean diesel similar to the mill in the 41-mpg Jetta TDI - named Green Car of the Year by Green Car Journal. VW says the engine produces 177 horsepower and a very respectable 258 pound-feet of torque. It's enough to propel the BlueSport to 60 mph in 6.2 seconds and a top speed of 140 mph. Power flows through a six-speed paddle-shifted DSG transmission with dual clutches. Start-stop technology helps improve fuel economy, and regenerative braking provides additional energy for on-board systems like air conditioning.

The styling, led by VW group design director Walter de'Silva, reflects the design language of the Scirocco and new Golf and looks like an angrier, more muscular Audi TT, though the front end also bears a similarity to the Honda S2000 - a car that, like the Lotus Elise and Miata, almost certainly would be the car's competitors should it see production.

"It is the symbiosis of outstanding technology and timeless Volkswagen design that makes this car an exceptional sports car," de'Silva said. "Its styling is clear and is reduced to the essentials."

VW is among the few automakers that didn't take a beating last year. Although sales were down for the industry as a whole, VW sold 6.2 million cars last year, a 6 percent increase over 2007. "We all know 2009 is going to be a very difficult year for the auto industry," Winterkorn said. "So far Volkswagen group has handled the market well."

We'd wager VW would handle the market even better if it built the BlueConcept.