First an SUV. Then a sedan. And now a hybrid. It may be another gut punch for purists, but Porsche's foray into volume products and new segments continues with a hybrid model for the new, second-generation Porsche Cayenne. However, the Cayenne S Hybrid isn't an overweight Toyota Prius. Both the hardware and the software feature unique-or at least unusual-approaches to hybrid execution. The result is that the Porsche Cayenne doesn't drive like any other hybrid.
Primary propulsion for the most efficient Porsche SUV is the 3.0-liter supercharged V-6 borrowed from the Audi S4, here producing 333 hp and 324 lb-ft of torque. As in all automatic-transmission Cayennes, power is transmitted to all four wheels through an eight-speed gearbox. An electric motor that measures 5.5 inches long sits just ahead of the torque converter, raising the total output to 380 hp and 428 lb-ft.
The final piece of hybrid-specific hardware is a dry multiplate clutch placed between the engine and the electric motor, and it's the hybrid Cayenne's most distinctive feature. The clutch can decouple the V-6 from the rest of the drivetrain, allowing the Cayenne to coast or move under electric power without the drag of a spinning engine. Pure electric mode is possible at low speeds and under light throttle applications, but you'll have to push through the kickdown switch to get the electric motor and the gas engine operating together, unless sport mode is activated. The Cayenne's calling card is a unique mode referred to as "sailing," also described as coasting or freewheeling. As soon as the driver removes a foot from the accelerator, the gasoline stops flowing and the clutch decouples the engine from the drivetrain, allowing the Cayenne to coast (at speeds less than 97 mph) without using gas or electricity.
Only a mile into our drive of the Cayenne S Hybrid, we were already impressed with the powertrain. It's the hybrid that you'd never know is a hybrid. One trip through the eight gears, and we were blown away by how much it felt like we were driving an SUV with only a supercharged gasoline engine. The transitions from electric to gas-only to electric-boost mode to sailing are barely noticeable unless you're looking for them. We had to rely on the tachometer and the powertrain display to discern what the complex powertrain was doing. We even had trouble identifying when the hydraulic brakes began assisting the regenerative braking system, all while staring at an analog gauge that showed exactly when the change happened. Our chief complaint is the slow shift times, whether the gearbox is left to shift on its own or controlled by steering-wheel-mounted buttons.
Unfortunately, the hybrid won't be offered with some of the Cayenne's most compelling chassis features, such as an active antiroll bar and a trick torque-vectoring rear differential, so it's not quite as fast or as confident in the turns. At 4938 pounds, it's also the heaviest Cayenne, but it is lighter than last year's V-8 model.
Official fuel-economy numbers for the hybrid Cayenne haven't been finalized, but they're expected to come in at 20 mpg in the city and 23 mpg on the highway. That won't make the Cayenne a standout, but it will slot right in the mix of large hybrid and diesel SUVs. The hybrid's cost premium is exactly $4000 over the V-8 Cayenne S, a price worth paying for those people who appreciate improved fuel economy. Unless you desire the $105,775 Turbo edition or insist on having sporty equipment like the fancy rear diff, the hybrid model delivers the comfort, drivability, and performance that a Porsche SUV should.
ON SALE: Fall 2010
ENGINE: 3.0L supercharged V-6/electric hybrid, 380 hp, 428 lb-ft