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 just 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.
New hybrid hardware
Ironically, primary propulsion for the most efficient Cayenne comes from what’s rightly considered a high-performance engine when installed in a lighter and lower automobile. Borrowed from the Audi S4 sport sedan, the 3.0-liter supercharged V-6 produces 333 hp and 324 lb-ft of torque. Power is transmitted to all four wheels through an eight-speed automatic transmission supplied by Aisin.
But it’s what’s between the engine and transmission that turns the Cayenne into a hybrid. An electric motor, measuring 5.5 inches long, sits just ahead of the torque converter. It’s good for 47 hp and 295 lb-ft of torque and raises combined output of the Cayenne S Hybrid to 380 hp and 427 lb-ft. Electricity for the motor and accessories like air conditioning and a hydraulic steering pump are supplied by a 1.85-kWh nickel-metal-hydride battery stashed below the cargo floor.
The final piece of hybrid-specific hardware is a dry, multiplate clutch placed between the engine and the electric motor, and it’s the Cayenne hybrid’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 (but not firing) engine.
It may sound complex, but the Cayenne’s powertrain looks quite simple and conventional when you view the technical diagram in our photo gallery. The path of the power flows naturally from the front of the car, starting with the supercharged V-6 and continuing through the clutch, electric motor (highlighted in red), torque converter, eight-speed automatic, and transfer case to the four wheels where it finally meets the road.
The hybrid system operates in five different modes. The first is pure electric operation, available at light throttle and speeds up to about 30 mph. A button labeled E-POWER on the center console alters the throttle map so there’s more pedal travel before the gas engine starts up. But even with E-Power active, you’ll need an absolutely flat road or a slight downhill if you want to maintain or increase your speed. At best, it’s useful for quietly, cleanly, and patiently motoring through your subdivision before you hit a main thoroughfare.
To activate boost mode, where the gas engine and electric motor work together for quick acceleration, the driver has to be asking for full throttle by pushing the gas pedal through the kickdown detent at the bottom of the pedal travel. However, if the Cayenne is in sport mode (activated with console-mounted button), electric boost comes on earlier, at about 70 percent throttle. Interestingly, the Cayenne never uses the gas engine and electric motor together during light acceleration.
Whether you’re in the city or on the highway, the most common situation is to simply use the gas engine. It may not sound that efficient or innovative, but remember that the 3.0-liter V-6 is significantly downsized compared to the 4.8-liter V-8 in the Cayenne S or the Turbo, or even the 3.6-liter V-6 in the base Cayenne. In this mode, the V-6 also drives the electric motor as a generator to charge the battery. By raising the powertrain load, the gas engine operates at a higher rpm and thus higher efficiency. So while more gas is being used, the energy recaptured for later use makes the net energy consumed lower than if the battery weren’t being charged.
Brake regeneration is the fourth operation, and a universal hybrid trick that uses the electric motor to slow the car and charge the battery. The Cayenne’s calling card, though, is a unique mode referred to as “sailing” by Porsche’s German engineers, because it’s the translation of their word for “paragliding.” In America, coasting or freewheeling is a more familiar descriptor. As soon as the driver removes their foot from the brake, the gas stops flowing and the clutch decouples the engine from the drivetrain, allowing the Cayenne to coast without using gas or electricity and with reduced parasitic drag. Unlike electric mode, sailing works at any speed. Or at least any speed you should expect to see on U.S. roads. Above 97 mph, the gas engine stays on at all times.
A different hybrid driving experience
Less than a mile into our drive with the Cayenne S Hybrid, we’re impressed with the powertrain. Why? It’s the hybrid that you’d never know was a hybrid. Or, at least a typical driver wouldn’t know it’s a hybrid. One trip up and down the eight transmission gears, and we’re blown away at how much it feels like we’re driving a SUV with a only a boosted gas engine. The transitions from electric to gas-only to boost mode to sailing are all seamless, and barely noticeable unless you’re looking for them. Thanks to the library-quiet cabin, you won’t even hear the gas engine kick on if you have the radio playing at a normal volume. Instead, we had to rely on the tachometer and powertrain display to discern what complexities were happening. We even had trouble identifying when the hydraulic brakes began assisting the regenerative braking, all while staring at an analog gauge that showed exactly when the change happened.
The real magic here isn’t in the electric motor, or the battery, or even that special clutch. The normalcy is a product of the automatic transmission and the hearty gas engine. When the media or enthusiasts bemoan a hybrid’s sluggish character, it’s rarely the electric bits damaging the character. Rather, it’s the incessant drone of a continuously variable transmission or an underpowered engine with the reluctance of a moody teenager that makes hybrid driving so mundane and tiresome. Porsche got a head start by choosing the right hardware and then mastered the calibration for a competent – even fun-to-drive – hybrid.
It’s worth noting that the gas-electric model is called the Cayenne S Hybrid, not simply the Cayenne Hybrid. That’s because this model is closer in character and equipment to the 400-hp Cayenne S than the base, 300-hp Cayenne. Lapping the 2.38-mile track at Barber Motorsports Park, the hybrid provides more instant throttle response thanks to the switch-like reaction of the electric motor. However, once its gas-powered peer has downshifted and reached the upper third of the tachometer, the regular Cayenne S runs a bit harder. Porsche tells us that the hybrid gets to 60 mph in 6.1 seconds, while the normally aspirated V-8 Cayenne S makes the sprint in 5.6 seconds. Unfortunately, the hybrid won’t be offered with some of the Cayenne’s most compelling chassis features like the active antiroll bar, or the fabulous torque-vectoring rear differential, so it’s not quite as fast or confident in the turns. At 4938 pounds, it’s also the heaviest model, though it is lighter than last year’s V-8 model.
Our hybrid Cayenne was equipped with the standard steel-spring suspension and rode nicely over the well-kept roads of Birmingham, Alabama. This setup doesn’t have the range adjustability, or body control of the more advanced air suspension and active dampers, but we imagine most buyers would still be content with it. Our largest gripe is shift speeds from the eight-speed automatic. Whether it’s left to shift on its own or controlled by the wheel-mounted buttons, the gearbox is never in a hurry to swap cogs. Whether they’re full-throttle upshifts or part-throttle downshifts, there was a noticeable delay between when we called for a shift, and when the Cayenne finally completed the action.
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 SUVs with the Chevy Tahoe Hybrid (21/22 mpg), the Mercedes-Benz ML450 Hybrid (21/24 mpg), and the BMW X6 ActiveHybrid (17/19 mpg). The Cayenne S Hybrid will also compete with the trio of diesel German SUVs, the BMW X5 xDrive 35d (19/26 mpg), the Mercedes-Benz ML350 BlueTec (18/25 mpg), and the Audi Q7 TDI (17/25 mpg). We expect the V-8 Cayenne S to be rated around 15 mpg in the city and 21 mpg on the highway.
Even the hybrid’s visual clues are subtle. From the driver’s seat, there’s just the E-Power button, a small analog charging gauge, a few special information screens on the nav system, and the tachometer that reads “Ready” in place of a zero. Outside, the only indicator is a pair of small fender badges. Stepping back, the second-generation Cayenne’s styling evolves for a more expressive and significantly less awkward look. The cabin receives a much-needed update to modern switchgear and finishes and adds a dose of Panamera design in the center console. The five-binnacle instrument cluster now features the tachometer in the center position, while a full-color display for vehicle information or a navigation map sits just left of it. The grab handles on either side of the center console are still in place and are now duplicated on the doors. Our favorite upgrade, though, is the new seating, with excellent bolstering and support.
A hybrid we can live with
Starting at $68,675, the Cayenne S Hybrid is exactly $4000 more than the Cayenne S. That’s a significant step up, but we think that’s a price worth paying for the people that appreciate the improved fuel economy. Unless you’re going to spring for the $105,775 Cayenne Turbo or insist on having the sporty equipment like the torque-vectoring rear differential, the hybrid offers the comfort, drivability, and performance that the Cayenne promises. True, the money saved in fuel costs may not recoup the $4000 premium, but then a regular Cayenne is hardly the epitome of rationality. In that view, it’s easy to justify the splurge on the innovative yet comfortably normal Cayenne S Hybrid.