Riding Shotgun in the 2014 Porsche 918 Hybrid
Is This Plug-In Hybrid the Future of Sports Cars?
We arrive at Nardo at daybreak. We barely slept an hour last night out of nervous anticipation for what comes today: a ride in a 2014 Porsche 918 Spyder prototype, the only one in the world. It's still winter in the heel of Italy, but the air is warm and there's a blue sky overhead. This is good news, because multimillion-dollar development prototypes and rain don't mix.
A Volkswagen Multivan deposits us at the remote test track where we find a gaggle of Porsche engineers at work, surrounded by all sorts of data-logging equipment. And there, in the middle of it all, is the 918.
The first ever Porsche 918 Spyder to run under its own means is nothing more than a rolling chassis pieced together so engineers can test its gasoline-electric hybrid drivetrain. Partly covered in modified Porsche 911 body panels and flaunting outrageous exhaust pipes that sprout up from the engine bay at the rear (a feature we're assured will be retained for production), it is a long way from the 918 Spyder concept that basked in the spotlight at the 2010 Geneva Auto Show.
Will Look Like the Concept Eventually
"The production version will be very similar to the concept car in overall appearance," Frank Walliser, chief engineer for the 918 program, assures us. "There will be some changes, like these tailpipes. This is really just a systems mule that we're using to sort the various gasoline-electric hybrid components and its electronics package before we begin construction of road-going prototypes back in Weissach (Porsche's research and development center in Germany)."
You should know the Porsche 918 Spyder by now. Mere months after its unveiling, Porsche confirmed it would put the targa-roofed supercar into production as a successor to the celebrated Carrera GT, starting on September 18, 2013. Just 918 examples are planned, each running down a dedicated line that is being established in a former paint shop at the carmaker's Zuffenhausen headquarters in Germany. It is the same factory that builds the latest Boxster and 911 — a holy grail to true Porsche fans, no less.
Waking Up the Engine
The Porsche engineers make some adjustments to the prototype's electronics, which are housed in a makeshift aluminum box strapped to an area that will eventually be occupied by the production car's rear spoiler. Walliser's boss, Wolfgang Hatz, Porsche's chief of research and development, slides down into the driver seat and twists a key in the left-hand-mounted ignition. Odd whirring sounds rise up from underneath before the gasoline engine catches and fills the garage with a deep pulsating blare of exhaust from those prominent tailpipes.
The centerpiece of the new Porsche is its mid-rear-mounted V8 gasoline engine, seated on traditional rubber mounts (rather than the hydraulic mounts used on the 911) within a carbon-fiber cradle that is attached to the back of the main tub by six prominent mounting points. Similar to the 90-degree V8 used in the Porsche RS Spyder successfully campaigned in the American Le Mans series between 2005 and 2008, the engine has gained 1.2 liters of displacement, going from 3.4 liters in race trim up to 4.6 liters in this application.
Walliser describes the engine as "entirely new," noting that it features an all-new crankcase, cylinder head design and low-reciprocating-mass internals, plus that radical exhaust system that sees two pipes exit just behind the integral carbon-fiber roll hoops. The point of this arrangement is to keep hot exhaust gases well away from the car's heat-sensitive battery pack mounted down low directly behind the tub.
Let's Talk About the Numbers
The revamped V8 has been tuned to rev to a dizzying 9,200 rpm (though in its current state of tune, it has a lower redline), and owing to its racing gene, Walliser promises it will deliver the same razor-sharp throttle response as the Carrera GT's 5.7-liter V10. Porsche engineers tell us the V8 makes about 562 horsepower.
But the 2014 Porsche 918 Spyder is a hybrid, remember, so it also has a pair of synchronous electric motors — one mounted up front acting exclusively on the front wheels with 107 hp, and a second, 121-hp motor attached to the rear of the gasoline engine providing drive to the rear wheels. We're told total system power will be in the neighborhood of 759 hp, with 568 pound-feet of torque.
Barely containing his delight at finally getting to show off the 918 Spyder to someone other than an engineer, Hatz gingerly guides the prototype out of the garage. After prodding the throttle a couple times to release some heat into the engine and its peripheries, he speeds off into the distance. We scramble back into the Multivan and catch up with the prototype at the end of an immense test track. The engineering team has spent the last 10 days here methodically running through the first systems test of the new car.
How It All Works
Like the Cayenne and Panamera hybrids, the 918 is a parallel hybrid, but its electric motors are obviously a lot more powerful and its battery pack is bigger (Porsche hasn't released a kWh capacity rating, but we know there are 312 lithium-ion cells rated at a maximum 202 kilowatts). The Spyder can be operated in either all-gasoline or all-electric mode, or when added performance is called for, a combination of both. In electric mode, it has a claimed range of 16 miles at speeds up to 93 mph.
Electric energy for the battery pack is collected on the overrun and during braking via a recuperation system claimed to operate up to three times more efficiently than the setup on the Cayenne and Panamera. You'll also be able to plug this car in, with an anticipated recharge time between 2 and 6 hours, depending on the available voltage.
Depending on which engine and/or motor combination is in use, the 918 Spyder is either rear-drive or all-wheel drive. The front electric motor runs a direct-drive unit, and an electronic torque-vectoring function apportions torque between the front wheels to benefit handling. The Porsche engineers tell us that drive to the front wheels is disengaged at 146 mph to improve high-speed stability.
Meanwhile, the gasoline V8 and rear electric motor are mated to Porsche's seven-speed, dual-clutch automated manual PDK transmission, which drives the rear wheels with the help of a torque-vectoring system and mechanical locking differential.
Finally, It's Our Turn
Hatz folds himself in two and uneasily steps out of the precious prototype wearing the biggest smile you've ever seen and, after some data-logging equipment is wired to various VGA sockets, diminutive Porsche test driver Holger Bartels takes his place behind the wheel. We're then asked if we'd like to be the first of a small group of media to ride in the 2014 Porsche 918 Spyder. We're halfway into the cabin, tripping over the wide sill, before we remember to answer.
It's snug, dark, and frankly a complete mess in the 918 prototype. Although the production car is set to receive a removable roof panel, the prototype sports a fixed structure. There's a three-spoke steering wheel from the 911, instrument pack from the Boxster and a stubby, cast-aluminum gear selector, along a sea of blue wires in front of our seat, which is borrowed from the 911 GT3. There's an 18.5-gallon gas tank mounted behind our seat. Almost apologetically, Bartels tells us this will all change by the time the new car reaches production. For now, it's one hell of an office.
Unaware the 918 Spyder had been idling in electric mode, we're suddenly whisked away from standstill with only the remote whirring of electric motors. Acceleration is stronger than we'd expected given the prototype's crude build. There's real shove and, as all sort of figures turn over on Bartels' monitor, a proper sensation of speed as grit from the road surface is picked up by the tires and fired into the wheelwells.
Beside us, Bartels points the prototype down a long straight. We accelerate beyond the 93-mph all-electric limit, and the gasoline engine booms to life. There's still a lot of tuning work to be done, but the free-revving V8 instantly provides an added dimension to the performance — both in terms of outright pace and aural attributes.
This car will offer five driving modes. There's "e power" for all-electric operation, a "hybrid" mode that allows either electric or gasoline operation, followed by "sport hybrid," which is the first of three performance-oriented gasoline-electric modes. Beyond that, "race hybrid" calls up even further levels of performance, while "hot lap" unleashes all the battery's remaining power for short periods of what Walliser describes as overboost.
How Quick Is It?
Nothing is official just yet, but Porsche is aiming for a curb weight around 1,700 kg (3,747 pounds), with 0-62-mph acceleration in less than 3 seconds.
Officials also hint at a 0-124-mph time of less than 9 seconds and zero to 186 mph in less than 27 seconds — quicker than the Carrera GT. Top speed, achieved with the help of a series of active aerodynamic functions including diffuser elements behind the front wheels and a multistage rear wing that extends to a maximum height of 4.7 inches, is pegged at 202 mph.
Still, there's more to this latest Porsche supercar than straight-line speed. Walliser also claims the production version will be capable of returning 78 mpg combined on the European test cycle. It's a headlining figure, of course, achieved primarily on electric drive. But even when driven for performance, the 918 Spyder will be capable of returning more than 30 mpg, we're told.
With a deft flick of the left-hand-side shift paddle, Bartels drops down to 5th gear, then 4th, and then he just stands on the brakes — which include giant 16.1-inch front carbon-ceramic discs and 15.4-inch discs in back. Still going hard, he turns into a tightening 180-degree bend and drops down again to 3rd before unleashing a combination of gasoline and electric power mid-bend. We're sideways. Bartels, still looking calm, winds on a touch of opposite lock and we fire back in the direction we have just come from, up into 4th, 5th and 6th gear, the hard blare of the gasoline engine combining with the whirring of the electric motors.
What About the Chassis?
The 2014 Porsche 918 Spyder prototype rides on a unique chassis made almost entirely from cast-aluminum components. The suspension is a combination of double wishbones at the front and a multilink setup in back, but unlike the system on the Carrera GT, which used a racecarlike pushrod system attached to the unit-body, the 918 has conventional springs and dampers sited outboard near the center-lock-style wheels, which measure 20 inches up front and 21 inches in the rear and are wrapped in 265/35R20 and 325/35R21 Michelin Pilot Sport Cup rubber.
It is all attached to the car's ultra-stiff carbon-fiber structure manufactured by Austrian company CarboTech via solid metal mounts. The dampers are adaptive, altering between comfort and sport modes at the push of a button on the center console in line with the PASM (Porsche Active Suspension Management) already offered on each and every Porsche model these days. To ease entry into suburban driveways and avoid expensive underbody scrapes on parking lot ramps, the front end offers 1.2 inches of ride height adjustment.
As on the latest 911 and Boxster, the steering uses electric power assist and automatically corrects steering lock to compensate for factors such as stiff side winds. It also provides a small degree of steering angle to the rear wheels, reducing the turning circle at lower speeds.
A Work in Progress
Despite the rough look of this prototype, it rides well on Nardo's smooth asphalt. As we rush up on a fast right-hander, we expect Bartels to back off. But he keeps on it, clearly confident of the car's dynamic properties. There's very little lean, hinting at a low center of gravity, and loads of purchase from the tires.
Walliser tells us computer simulations suggest the production car will be capable of generating up to a 1.4g on the skid pad (though that's a maximum figure, rather than the average lateral acceleration we customarily report). He also drops a Nurburgring claim: Porsche is targeting 7 minutes, 22 seconds on the Nordschleife — still well short of the Dodge Viper's 7:12, but moving nonetheless.
Even in early prototype form, the 2014 Porsche 918 Spyder is hugely impressive. There's still a long way to go — another 18 months of intensive development, no less. But as our ride comes to an end, we're struck by just how far Porsche's engineering team has come during just 10 days of development work on the rolling chassis.
In the next phase, Porsche will build 23 road-going prototypes. Stay tuned.