|Auto Bild test data for 8 of the cars, rendered as fuel economy (mpg US) rather than fuel consumption (l/100km). Click to enlarge.|
While it may seem intuitive that driving at higher speeds consumes more fuel, exact data on just how much a difference that makes model-by-model isn’t readily available. The editors at the German weekly Auto Bild recently changed that, however, publishing (12 May 2006) a head-to-head comparison of the fuel consumption of 16 different models of cars under higher speed driving conditions.
Testing was done at the Automotive Testing Papenburg (ATP) 12.5 km high-speed circuit in Germany. The editors measured fuel consumption using on-board computers at speeds of 80, 100, 130, 150, 180, 200, 220, 250 km/h and at top speed.
The guzzler of guzzlers was the Porsche Cayenne Turbo S, which swills down an eye-popping 66.7 liters of fuel per 100 km at a top speed of 270 km/h—that’s 3.5 mpg US at 168 mph. Of more prosaic interest was the difference in performance between diesel and gasoline versions of the same cars, as well as some data gathered on the difference a bicycle carrier on the roof can make, or driving with the top down.
|BMW 5 series diesel and gasoline. Click to enlarge.||The downsized VW twin-charged TSI vs the larger diesel. Click to enlarge.||GM Opel Zafiras. Click to enlarge.|
|Prius data is included on each chart as a reference.|
Adding a rooftop bicycle carrier to the BMW 530i Touring model increased fuel consumption by 11% at 100 km/h (62 mph). That gap increased to 26% at 180 km/h (112 mph).
Driving a Mercedes SLK 200 K with the top off imposed a 5.8% penalty on fuel consumption at 100 km/h.
(A hat-tip to George Minko!)