New York Auto Show: 2013 Porsche Cayenne Diesel Introduced on Wednesday, April 4: 2013 Porsche Cayenne Diesel. The long-awaited diesel variant of the Cayenne sport utility vehicle. The Cayenne accounts for roughly half of all Porsche sales in the United States. Limited-edition 911s are well and good, but the brand expects meaningful market penetration from the big diesel. It is also follows in a long tradition of Porsche diesels dating back to its tractor-building days. What they said: Detlev von Platen, president and chief executive of Porsche Cars North America, said the automaker hoped for the Cayenne Diesel to account for "10 to 15 percent" of total Cayenne sales. What they didn't say: The diesel-powered S.U.V. could take a bite out of sales of the more expensive and less fuel-efficient Cayenne S Hybrid. According to Porsche, the Cayenne Diesel should average 28 miles per gallon during highway driving and 23 m.p.g. over all. The Cayenne Hybrid delivers 24 m.p.g. on the highway. Don't let the modest power number fool you. The 240-horsepower turbocharged 3-liter V-6 is all about low-end torque - in this case, 406 pound-feet of it. Scheduled to arrive in American showrooms later this year, the Diesel has a starting price of $56,725, roughly $8,000 more than the base Cayenne. Porsche claims 740 miles of range on a tank of fuel, but a driver would have to travel long and far to soothe the bite of that price premium. The Cayenne S Hybrid, however, starts at $70,825. Save for a tiny badge on the rear liftgate, there are almost no visual clues to distinguish the diesel from its stablemates. Of course, considering its epic road-trip range, they might be distinguishable by the speed with which occupants vacate their seats at highway travel plazas.