918 Spyder PHEV tech trickles down to the execusedan
Electrons are nothing if not democratic. They’re equally eager to illuminate a dim bulb in a mud hut as they are to hasten the acceleration of a Porsche 918 Spyder. Porsche first harnessed electrons for propulsion in 1900 with the AWD Lohner-Porsche Mixte Hybrid, reviving the idea in 2010 with the Cayenne S Hybrid. But until now, except for that headline-grabbing 918 hypercar, every other hybridized Porsche has been an entry- or mid-level V-6 variant. Well, the wait for an—ahem—“affordable” range-topping V-8 hybrid Porsche is over.
Meet the Panamera Turbo S E-Hybrid—sort of a 918 with the engine relocated to the front to make room for big comfy chairs in back. Not really. Actually, no part numbers of consequence get shared between the hypercar and this sedan. But the decision to electrify the top dog second-gen Panamera leveraging 918 technology was made just as the Spyder was getting off the ground. Developing this sedan powertrain from scratch without copying off the 918’s homework would not have been practical—especially the complex control strategies for blending the combustion and electric power under acceleration and the regenerative and friction forces during braking. McLaren and Ferrari aren’t in the sedan biz, so it might be a while before a true competitor emerges.
The beating heart of this beast is a 542-hp, 567-lb-ft twin-turbo V-8 bolted to a 134-hp, 295-lb-ft electric motor that fills the otherwise emptyish space in the bell housing of a spanking new ZF eight-speed PDK transmission. The electrons it employs flow in and out of a 14.1-kWh battery pack. Do the hybrid math (or strap one to a dyno), and you end up with 671 horsepower and an impressive 627 lb-ft of torque that remains constant across a ludicrously broad band from 1,400 to 6,000 rpm.
Now about that “affordable” part: The $185,450 USD asking price (add $10,400 USD for the long-wheelbase Executive version) represents a tiny fraction of the going rate for a 918 Spyder, but the premium over the next-swankiest Panamera Turbo is a steep $37,500 USD. The claimed 0-60-mph time of 3.2 seconds and top speed of 192 mph (309 km/h) only outpace the base Turbo by 0.4 second and 2 mph (3.2 km/h), so that doesn’t pencil out too flatteringly. The Euro-spec gas/electric combined fuel economy rating is 81 mpg-e, but let’s assume nobody’s buying this car for that. Relative to the V-6 Panamera 4 E-Hybrid we recently drove in South Africa, the V-8’s 215-hp, 111-lb-ft improvement nets a 1.2-second drop in 0-60 mph and a 20-mph (32 km/h) boost in top speed, but the price difference would buy a second base Panamera ($85,000 USD).
Not to worry. The filthiest-rich people don’t want two cheap Panameras; they want one fabulous one. And Porschephiles looking to avert a purchase veto from a pragmatic left-brain spouse can point out that adding the cost of the Panamera Turbo options that become standard on a Turbo S E-Hybrid—big ticket performance-enhancers such as $8,960 USD carbon-ceramic brakes, the $5,000 USD Porsche Dynamic Chassis Control with torque vectoring, and lesser items such as the Sport Chrono package, 21-inch wheels, and sybaritic extras—to the $10,000 USD value of the E-Hybrid gear pretty much covers the price spread. (If that doesn’t work, mention that the battery can precondition the car to the desired temperature via smart-phone app.)
We sure hope that at least some buyers have racetrack club memberships because this rig digs track time. During a hot 2:52.2 lap of Porsche’s 3.9-mile (6.3-km_ Nardò handling circuit in Italy’s boot-heel with Porsche test driver Lars Kern at the helm (he set a 7:38.40 Nürburgring lap time in a Panamera Turbo last June) three passengers enjoyed decidedly unsedanly g forces in all directions—levels that the car’s rear entertainment self-reported as 1.16 g turning left and 1.48 turning right (always on an even keel, thanks to the 48-volt active anti-roll bar system), and 1.34 g during our slingshot launch. The comparatively modest 0.87 g braking force reported suggests there was plenty of regen-braking going on, allowing 0.3 g of that energy to go back into the battery (running in Sport+ mode, the powertrain assists in keeping the battery topped up). Indeed, after two three-lap sessions, the reported electric range only dropped from 23 to 19 miles (37 to 31 km). And with no cars to pass, Lars never pressed the Sport Response (press-to-pass) button, which maximizes E-boost for 20 seconds. Might this E-Hybrid eclipse the Turbo’s ‘Ring time? Maybe. It weighs 700 pounds (317 kg) more, but the weight-to-power drops from 8.0 to 7.6 pounds/hp (3.6 to 3.4 kg/hp) and its center of gravity moves aft a skosh and down 0.4 inch.
Speaking of modes, the others mirror those on the 4 E-Hybrid: E-Power, the default which prioritizes electric driving and depletes the battery most freely; Hybrid Auto mode, which blends gas and electric power most efficiently; and the two Sport modes, which both keep the engine on and prioritize electric assist with the non-plus mode maintaining a constant battery level instead of maximizing battery charge.
Later this summer we’ll take the helm ourselves to determine whether the Turbo S E-Hybrid is more four-door 918 or crazy-pricey Panamera Turbo.
This new hot-vee twin-turbo 4.0-liter V-8 is smaller, more powerful, 44 pounds (20 kg) lighter, and more efficient than the one it replaces. Its two twin-scroll turbos spool out 1.4 bar (20.3 psi) of boost with minimal lag, thanks to the very short trip the pressurized air makes from either turbine through an intercooler to the inlet valves. Those inlet valves enjoy variable timing and lift (the exhaust valves get variable timing only), and enabling cylinder deactivation between 950 and 3,500 rpm greatly reduces throttling losses under light loads (184 lb-ft max). The sand-cast aluminum block gets a new type of atmospheric plasma-sprayed 150-micron-thick iron coating applied. This, in combination with chrome-nitride-coated piston rings, greatly reduces friction. The basic architecture is shared with the EA839 V-6 also employed in the Panamera. Expect to see this V-8 engine rolling out at Audi and Bentley for sure, and probably in Lamborghini’s SUV.
ZF 8DT eight-speed PDK transmission
Developed by Porsche and built by ZF, this box is now standard on all Panameras. It adds an extra cog and the option of hybridization in essentially the same package envelope as the seven-speed PDK box it replaces with mass increasing by only 3 pounds (1.4 kg). The gear ratio spread is an impressive 11.2 (up from 10.2), with first gear unchanged from the seven-speed PDK’s and a top gear that’s 10 percent taller. Internal power loss in the transmission is said to be 28 percent less, thanks to friction reductions, a demand-driven lubrication system, the wide gear ratio spread, and optimized electronic control of the gearbox. The gearbox can also provide on-demand clutched power takeoff to the front wheels with a variable torque split from 4/96 percent front/rear torque bias to 50/50. This box helps improve fuel economy by 1.4 percent.
Samsung SDI Battery
This pack features eight modules of 13 prismatic lithium-ion battery cells each on two levels cooled by a dedicated coolant circuit. Operating voltage is 381 volts, and its peak output is 128 kW (172 hp) for 10 seconds. The system is designed to utilize 11.3 kWh of the 14.1 kWh total capacity, discharging only as low as 15 percent, and topping up to just 95 percent. The pack weighs about 280 pounds (127 kg) and measures 32.6-by-17.3-by-9.4 inches. It’s water tight, and it rides outside the bodywork under the rear deck in the space where unelectrified Panameras package a well containing the 12-volt battery and sound-system subwoofer. These items move into the auxiliary storage cubbies off to either side of the rear of the cargo area, reducing Euro DIN cargo volume from 17.5 to 14.3 cubic feet. But by the SAE hatchback measuring methods, we don’t expect the 17.4-cu ft volume to change. The hardened aluminum case has been safely crash tested at high speeds, thanks to mounts that direct it to move down and away from the passengers instead of remaining fixed, rupturing, and potentially catching fire.
|2018 Porsche Panamera Turbo S E-Hybrid|
|VEHICLE LAYOUT||Front-engine, AWD, 4-pass, 4-door sedan|
|ENGINE||4.0L/542-hp/567-lb-ft twin-turbo DOHC 32-valve V-8 plus 134-hp/295-lb-ft electric motor; 671 hp/627 lb-ft comb|
|TRANSMISSION||8-speed twin-clutch auto|
|CURB WEIGHT||5,100-5,300 lb (mfr)|
|LENGTH X WIDTH X HEIGHT||198.8-204.7 x 76.3 x 55.7-56.2 in|
|0-60 MPH||3.2-3.3 sec (mfr est)|
|EPA CITY/HWY/COMB FUEL ECON||Not yet tested|
|ON SALE IN U.S.||Fall, 2017|