Vauxhall VXR8

Vauxhall VXR8

If you’re wondering how a big sedan powered by a 6.2-liter V-8 engine can win a competition focused on high mpg, here’s a quick explanation of the challenge itself.

One of the challenges of the Fleet World MPG Marathon recognizes those drivers and their cars which record the greatest percentage improvement over the manufacturers’ published gas mileage ratings.

In the case of the Vauxhall VXR8, the European cousin of the Holden Commodore HSV GTS and now defunct Pontiac G8 GXP, drivers Andrew Duerden and Chris Mooney achieved the best percentage increase of any other car in the competition, bettering the VXR8's quoted mpg figures by 53 percent.

Yes, the Vauxhall VXR8 still features a 6.2-liter ‘LS3’ V-8 complete with 425 horsepower and 405 pound-feet of torque.

Its official gas mileage numbers come in at 17.5 mpg on the European combined cycle but Duerden and Mooney managed to get this figure up to 26.7 mpg over a course of 350 miles of mixed city and highway driving.

“It just goes to show that the person behind the wheel can make a massive difference to fuel costs and carbon emissions,” said Mooney.

We suspect there were a lot of early up-shifts, coasting, and barely any throttle throughout the drive. In other words, a sad way to drive such a sporty sedan but perhaps a reasonable way when on public roads.

The overall champion of the event, awarded for attaining the highest mpg figures, was the Smart ForTwo Cdi, a diesel model unavailable in the U.S. market. In the hands of eco-driving expert Mick Linford it achieved over 68 mpg, according to our sister site GreenCarReports.