Cayenne S Hybrid is a Powerful Environmental Move for Porsche

A bit of disclosure: I’ve approached the thought of a Porsche hybrid with some degree of caution. My car in high school was a ‘57 Porsche 356A restoration project, an ideal choice to nurture the ‘car guy’ spirit during impressionable teenage years. Later, in my hot rod phase, it was customized 914 and 924 Porsches, the latter painted Ferrari Red and styled with a fiberglass kit that looked hauntingly like the ‘new’ Porsche 944 that would emerge at showrooms a year later. Then it was a Porsche Boxster S, a pocket rocket in red that couldn’t help but bring a smile while carving any turn. I’ve test driven many Porsches over the years back when I was editor of Porsche Classics magazine, so I definitely know this brand.

And so the coming Cayenne S Hybrid posed a challenge in my mind. Clearly, it was the right evolutionary move for Porsche, but it just couldn’t … possibly … be ‘eco’ in the sense of sacrificing the brand’s tight and delightful Teutonic performance in favor of fuel efficiency. It had to offer both, seamlessly. Porsche engineers could do this, right?

In a word, ‘yes.’ Recent time spent behind the wheel of an advanced prototype Porsche Cayenne S Hybrid in Southern California proved not only that it could be done, but would be in classic Porsche style and without sacrifice.

The hybrid Cayenne is fast, responsive, tight. Energy-efficient electrohydraulic steering provides good road feel. It can be driven in electric-only mode up to 30 mph for a maximum 1.2 miles with a light touch on the accelerator. Both the combustion engine and electric motor combine to provide power for brief stints when maximum acceleration is needed. Unique to the Porsche hybrid system is a coasting feature that disengages the powerplant under no-load conditions when driving below 86 mph, a nod to boosting fuel efficiency. Power comes on line again upon accelerator input.

When the Cayenne S Hybrid comes to new car showrooms in 2010, Porsche buffs will enjoy a model that’s not only about 25 percent more fuel efficient than a standard variant with super-low ULEVII tailpipe emissions levels, but also one with copious amounts of performance. In fact, under hard acceleration, the combination of the two powerplants provides a very satisfying launch with 405 lb-ft of peak torque at just 1,500 rpm. As Porsche likes to say, the car is based on a six-cylinder, but it combines the power of an eight-cylinder with the fuel consumption of a four-cylinder. It’s the ‘new math’ of the advanced automotive world.

Porsche took a straight approach to creating its first hybrid, literally. The addition of a 52 horsepower electric motor and disengagement clutch in line between the Cayenne’s supercharged 333 horsepower, Audi-derived 3.0-liter V-6 and Porsche’s first-ever 8-speed automatic transmission works best with the existing Cayenne platform and powertrain layout, Porsche execs point out. Power electronics modules are located up front in the engine bay with a 288 volt, 38 kilowatt hour Sanyo nickel-metal-hydride battery at the rear.

While our drive on streets and freeway allowed a good sense of this developmental hybrid, there was no instrumented testing element available so we’ll just pass along Porsche’s specs: a combined 374 horsepower maximum system output brings 0 to 62 mph (100 km/h) acceleration of 6.8 seconds and an electronically governed top speed of 133 mph. Fuel economy is projected to be about 27 mpg.

No sacrifices have been made to accommodate the hybrid system since the hybrid module is a compact 5.8 inches in length and the 154 pound, 240 cell NiMH battery is completely enclosed in the space that normally houses the Cayenne’s spare tire. Off-road capabilities are retained and towing capacity is a substantial 7,000 pounds.

So … our overall impression? We like it, not just from an environmental perspective, but also from a performance perspective as well. It strikes a delicate balance that’s true to the brand. The Cayenne S Hybrid’s destiny was never that of a 50 mile-per-gallon eco champion, but rather a premium crossover SUV with significantly improved fuel efficiency and lower environmental impact. On that account, mission accomplished. Many hybrids tune in on efficiency quite well but seem to leave the love of driving behind. The Cayenne S Hybrid is not one of them.