It may be a variation of an established model, but in reality, the newest addition to the Cayenne range represents a very big step for Porsche, both technically and philosophically. It is the Cayenne Diesel.
The very thought of a production diesel Porsche would once have been anathema to the company and its clients. But times change, and in a world in which low CO2 engine emissions are the stamp of responsibility, particularly for SUV vehicles, a diesel-engine Cayenne was inevitable, if late in appearing. By now some 86% of premium SUVs in Europe are diesel powered.
Porsche uses a version of the 3.0-L V6 turbodiesel that is also fitted to its increasingly close relations—the Volkswagen Touareg and the Audi Q7.
Together with the gasoline hybrid system that is now in its final phase of development for launch in the next-generation Cayenne S and Touareg for MY2010, the new direct-injection gasoline engines fitted to its sports cars, and now its first diesel, Porsche is sending out a clear message about its determination to embrace both heightened social responsibility and high performance.
In fact, by Porsche standards the Cayenne diesel is not particularly high-performance, but in SUV terms, it performs convincingly well. The engine has an output of 176 kW (236 hp) and peak torque of 550 N·m (406 lb·ft) at 2000 rpm. Top speed is 214 km/h (133 mph) and 100 km/h (62 mph) is reached from rest in 8.3 s. A six-speed Tiptronic S transmission is standard.
To extract full power from the engine when maximum traction or acceleration is needed, the engine management briefly switches off the alternator and air-conditioning compressor up to 2500 rpm.
NEDC (New European Driving Cycle) combined fuel consumption is 9.3 L/100 km with CO2 emissions of 224 g/km. In Porsche’s established tradition, the Cayenne has a large fuel tank of 100 L (26.4 gal), so its theoretical range is some 1000 km (620 mi).
The car’s diesel engine has an 1800-bar (26.1-ksi) common-rail system, piezo injection technology, a VTG (variable turbine geometry) turbocharger, an intercooler, and EGR (exhaust gas recirculation). The engine is thermally highly efficient, so an additional cabin heater system is fitted.
The transmission’s torque converter has two lockup clutch friction discs as used on larger engined Porsche applications. As a fuel-saving measure, the transmission automatically shifts to neutral when the driver depresses the foot brake with the vehicle stationary on a level surface.
A sports mode sharpens the transmission’s responses, changes the accelerator control map, and, when fitted, switches the PASM (Porsche Active Suspension Management) to a more dynamic setting. PASM with air springs gives three damper settings and six body-height adjustment levels over a 110-mm (4.3-in) range. PSM (Porsche Stability Management) is standard on the Cayenne diesel, which gets steel springs as standard.
Intelligent PTM (Porsche Traction Management) is set to 62:38 rear/front bias as a default.
Acoustics control is important in a premium diesel product. The new Cayenne’s windshield incorporates a layer of laminated, sound-deadening glass to reduce what Porsche terms underhood transmitted "humming frequencies," adding that "a special fleece material" is used to attenuate sound above the gasoline Cayenne’s damping. Compared to conventional sound-deadening packages found on diesel vehicles, Porsche revealed that its system saved a very significant 20 kg (44 lb).
As for external aesthetics, there is no identification that the Cayenne is a diesel. The interior giveaway is the rev counter marking, and the best indication that the Cayenne is a diesel is the picture under the hood.