Jonathan Gitlin











Elle Cayabyab Gitlin

In the next few months, Porsche is going to launch the Mission E, a sleek and powerful electric vehicle that might just be the most competition the Tesla Model S will have faced to date. However, the company has been electrifying some of its range for some time now.

We'll have to wait a while for better battery tech before we get a plug-in hybrid EV (PHEV) 911, Boxster, or Cayman, but Porsche's Panamera and Cayenne range are available now with a side helping of lithium-ion. The first PHEV Porsche appeared in 2014 in the second-generation Cayenne. It impressed us when we tested it last year, beating less powerful plug-in SUVs from BMW and Volvo when it came to fuel economy and driving fun. But the boffins in Stuttgart have been tinkering with their PHEV tech, adding more kWh, horsepower, torque, and generally refining all the software and control electronics that make everything work. They've done a fine job, if our time testing the $104,000 Panamera 4 E-Hybrid Sport Turismo is anything to go by.

Porsche invented the hybrid?

When you think Porsche, you probably picture a 911, the rear-engined sports car now in its 55th year of production. Or maybe the name calls to mind Steve McQueen racing down the Mulsanne Straight in a blue-and-orange blur. But did you also know the company invented the hybrid automobile back in 1900? The Lohner-Porsche Mixed Hybrid—also known as "Semper Vivus"—was one of Ferdinand Porsche's first creations, using a pair of single-cylinder engines coupled to 2.5kW generators that fed power into a massive battery pack. The technology didn't catch on at the time, but fast forward more than a century and today the company is still a leader in hybrid technology.

In 2010, it launched the Cayenne S Hybrid, which added some nickel-metal hydride batteries to the big off-roader. That same year, it experimented with a mechanical flywheel as an energy store in the 911 GT3 R race car, technology that then went on to be used by Audi's diesel-powered Le Mans racers. When it was time for Porsche itself to return to Le Mans with the 919 Hybrid, the company went a more conventional route, combining a turbocharged V4 gasoline engine with two hybrid systems powered by an array of lithium-ion cells. A similar approach was used for its 918 Spyder, which featured a V8 engine derived from the RS Spyder race car, 6.8kWh of lithium-ion storage, and a price tag that wouldn't leave a lot of change from a million bucks.

As is the way in the automotive world, that technology has been trickling down to Porsche's mass-production range. The current 911 and 718 sports cars feature a lot of the same engine technology as the 919 Hybrid's internal combustion engine, for instance. For now, Porsche is holding back from hybridizing its sports cars, citing weight and size as a reason to hold off for the promise of solid state batteries. But it has no such reticence when it comes to adding some juice to its four-door range. The third-generation Cayenne SUV has a PHEV variant coming—some of our friends at other publications were off driving it in Germany last week, in fact, but it's yet to go on sale here in the US.

For now, you can buy several different PHEV Panameras, depending on whether you want the regular sedan version or the Sport Turismo body style we tested here. There's also a choice of two powertrains. Over in Europe, where it went on sale in June 2017, the E-Hybrid versions now account for 60 percent of all Porsche Panamera sales. We got the model much later in the US, but, if I'm reading the sales figures right, in April it made up about a third of Panamera sales. A review of the full-fat, 680hp Panamera Turbo S E-Hybrid will have to wait a few more weeks, so today we're just going to discuss the "lesser" 4 E-Hybrid.

Porsche

Porsche

Porsche

Porsche

Under the skin

The internal combustion side of things is courtesy of a 2.9L direct-injection twin-turbo V6. This provides the Panamera 4 E-Hybrid with 330hp (246kW) and 331ft-lbs (450Nm)—essentially the same as the non-hybrid 3.0L V6-powered Panamera 4. Between the engine and an eight-speed version of dual-clutch gearbox (Porsche Doppelkupplung, or PDK) is an electric motor rated at 136hp (100kW) and 295ft-lbs (400NM). It's worth noting that the total power and torque output for the powertrain is a little less than the sum of its parts, but 462hp (345kW) and 516ft-lbs (700Nm) is still more than adequate for a vehicle with a curb weight of 4,828lbs (2,190kg). The electric motor is a development of the one in the older Cayenne hybrid we tested, and the older system's electro-hydraulic internal combustion engine decoupler has been replaced by an electromechanical system that provides shorter response times.

As you might expect, the E-Hybrid uses liquid-cooled lithium-ion batteries, located behind the rear seats and underneath the floor of the trunk. The pack is the same weight as in the previous generation of Panamera PHEV, but it's now 14.1kWh (versus 9.4kWh). Charging from empty to full takes 12 hours at 120V or three hours with a 240V level 2 charger if you spec the 7.2kW onboard charger (an $840 option). Porsche claims 31 miles (50km) of electric-only range, although that's based on Europe's NEDC cycle. The EPA, which seems to get much closer to real-world EV range, figures the Panamera 4 E-Hybrid at 16 miles (26km) with a combined 46mpge, or 22mpg when using gasoline alone.

As the electric motor is positioned upstream of the gearbox, it will send power and torque to—and recover kinetic energy under deceleration from—all four wheels (the "4" in Panamera 4 E-Hybrid means all-wheel drive) compared to PHEVs like the BMW i8 or Volvo XC90, which use their internal combustion engines to power one axle and their electric motors to power the other. Distribution of the powertrain's power and torque to the wheels is handled by the Porsche Traction Management system, one of an array of electronic systems that control the Panamera. It sends most of it to the rear wheels by default, but the vehicle can send 100 percent of available torque to either axle if road conditions necessitate. (A torque-vectoring rear differential is also available as an option, although our test car wasn't fitted with one.)

The suspension is a double-wishbone arrangement with adaptive air suspension at each corner. Our test Panamera was also equipped with rear-axle steering ($1,620), which enhances cornering stability at higher speeds by turning the rear wheels in the same direction as the front, effectively increasing the wheelbase. At low speeds, it boosts maneuverability by turning in the opposite direction to the front wheels, effectively reducing the wheelbase. All Panamera 4 E-Hybrid Sport Turismos also get the Sport Chrono package as standard. This is most obvious from the stopwatch mounted atop the dashboard, but this package also gives you access to Sport Plus mode, more on which shortly.

Listing image by Jonathan Gitlin