Is this a hypercar that happens to be a hybrid. Or a hybrid that happens to be a hypercar?
Some say neither. We say both. The performance certainly is hyper. The straight-line figures are staggering, thanks to 875bhp delivered by a screaming V8, plus electric power, and four-wheel-drive. Porsche claims 0-60mph in 2.5 seconds, and 0-125mph in 7.2, and 0-186mph (300kph) in 20.9. That's Veyron-fast up to 150-odd mph.
And it's not just a straight-line drag merchant. The 918 has famously lapped the Nurburgring in 6 minutes 57 sec. That number is on par with deadly rival McLaren's claim for the P1 of 'under seven minutes'.
But while the P1 is a track-attack 2WD machine, the Porsche is more dual-purpose. Charge it from a socket and you can drive several miles at hot-hatch speeds before you ever start the engine. Hence the hybrid emphasis too.
Driven in the normal EU cycle it makes 94mpg and puts out 70g/km. But you won't buy it to save fuel or tax, because it costs the Euro equivalent of £715,000.
How does it actually feel?
It's a honey. My Top Gear colleagues who've driven the McLaren P1 say that car will bite your arm off as soon as look at you. The 918 is rather different. Thanks to four-wheel-drive, four-wheel steer, a computer-controlled torque vectoring system and a rear e-diff, it'll do all it can to keep you going in the direction you've pointed it. And with all that electric assistance, you don't even need to be too attentive to what gear you're in. Immense, instant-on thrust and traction are right there, anywhere round the rev dial.
It turns in sharply. If it's wet or the tyres are cold and the ESP's off, the back end will edge out under brakes, but really that's not the car's natural state. In the dry you can brake deep into a bend. There's plenty of feel through steering wheel that's sharp and progressive rather than over-direct. Sure you can cut off the ESP, but even so it doesn't want big slides. Through the apex of slow or fast corners it's very neutral, and tells you the limits clearly. Ridiculously high limits, naturally. You can get on the power very very early and it will just catapult out of most bends and down the straight.
Get on the power even earlier, and it will edge the rear out again, especially in the wet. But controllably. Or if the stability controls are off and you're in second gear, there's no way the tyres can cope with that power, and it's an easy spin.
And what about that powertrain?
Two things strike you about the power. First, the amount of it. And second, how easy it is to get at. At low revs you hear the whine of the electric motors, but by about 3000rpm, that epic flat-crank V8 is starting to get your attention. At that point the noise is hard and gutteral. Beyond, it's a simple, hard-edged, take-no-prisoners howl that rises and rises towards the 9150rpm top end, by which time every particle of your flesh and bones is in a state of quivering excitement.
It needs absolutely no allowances from you. The delivery is progressive and the throttle as instantly sharp as a knife-cut. At low and middle revs, the arrival of the surge is as brutal as a big turbo engine, but with none of the lag or softness. As soon as you so much as think about moving your foot, the power's there for you, propelling you into the next dimension.
I did some laps following Walter Rohrl who was in a 911 Turbo S - itself a blindingly fast car by almost any standard. In the slow corner before the main straight, I'd take an extra tight inside line, just to exaggerate the feel of the steering and the balance. The Turbo S would go catapulting off own the straight, becoming a thimble-sized spot in the distance. I'd floor the 918. By half-way down the straight it'd have reeled him in and I'd be cruising on part-throttle, wondering what's for lunch.
And can it stop?
Because it's got electric motors at the front and rear, the 918 can do properly strong road-level braking using them alone. That's regeneration, recharging the batteries like a racing car using KERS. This is strong enough to stop the car at 0.5g. But even that isn't enough on the track, so the car also has a set of huge carbon-ceramic discs. A new electronic controller hands off the braking power between the regenerative system and the discs.
There are times when that hand-off can be a little woolly. And the initial bite is a bit disappointing too. But there was never a moment on the track when I thought the car wouldn't stop like I wanted it to. And it's so stable you can brake late and deep into a corner - another handy way of catching 911 Turbos.
And on the road?
Again dominated by the V8's feral sounds, and the pops and chunters during light-throttle gearshifts. The ride is actually pretty flat and surprisingly supple, the dampers breathing nicely and the springs taking the harshness off. The steering is great, never twitchy, and varying its weight nicely as you sweep over dips and crests around a corner. You feel intimately connected.
What's so darned special about the engine?
It's derived from a race engine, the one out of the 2005 RS Spyder race car. Every part is new though, to make sure it's durable and OK in traffic. Even so, the spec is pretty compelling. Even without the help of the electric motors, it makes 603bhp from just 4.6 litres. It revs to a dizzying 9150rpm, and uses a dry sump. At just 135kg, it's astoundingly light, and it exhausts through upward-firing pipes amid the V. Which sounds like the arrival of a swarm of very angry mutant horror wasps played through AC-DC's sound system.
The capacity, power, torque and rev profile of the Porsche's V8 are eerily similar to the engine in the Ferrari 458 Speciale. And yet the Porsche is decisively faster. Which pretty comprehensively rebuts the whingers who say Porsche should have made the 918 as a lighter non-hybrid car. It's clear the 314kg of battery, electronics and motors are more than pulling their weight.
At the back axle, the V8 engine and the electric motor are coupled together and drive through the seven-speed PDK transmission. In any given gear, the motor is at its torquiest at low revs, and then at medium-to-high revs the V8 hits its mighty stride and takes over. The e-motor's torque is 276lb ft at up to 2000rpm. The petrol engine hits 398lb ft but not until 6700rpm. So the motor fills in while the engine isn't quite awake. There's another, smaller, electric motor at the front.
There is really no other way you could get this instant yet brutal power delivery with any other solution than the small-capacity race-type engine plus hybrid. Lose the hybrid you'd be short of torque. Try to recover the torque through turbos and you'd get lag. Try to recover it by building a bigger engine and you'd lose the thrill of 9000rpm.
How does the four-wheel drive work?
Although the rear electric motor runs through the seven-speed gearbox, the front electric motor has just one gear, its ratio chosen to give most drive at low-to-medium speeds. In fact at 165mph the front motor is decoupled entirely to avoid over-speeding it. In other words, at high speed the 918 is RWD only. But you won't spin your wheels at those speeds because you'll be in a high gear, so 4WD is unnecessary. Whereas in low gears, you're extremely likely to get wheel-spin from the rears, so some balancing front traction is welcome.
By controlling the electrical power to the front and rear motors, the car can instantly vector its own torque. Plus there's four-wheel-steering keeping you stable. As soon as the rear wheels spin up, the car is designed to send more torque to the fronts. No drifting please.
Does it run like a Prius and turn its engine off?
Not in sport or race modes. Because of the braking regeneration, the engineers say that most drivers (not the really hard ones like Walter Rohrl, but most of us) will never deplete the battery when lapping a track. Which means even going fast, this is an economical and efficient car.
There's also a 'hot lap' mode, allowing you to go past a soft limit on the throttle pedal and drain the battery. The idea is you arrive at the start of the long final straight at the 'Ring and floor it, and finish the lap with the battery down, the car spent. They really are 'Ring obsessed.
Does the aero make a difference?
As with other hypercars, the vast rear wing has several positions. There's also an extending rear spoiler below that wing. They retract at slow speeds, but will go into a high-downforce mode for quick cornering or a feathered mode for making an assault on the 214mph top speed. They're balanced by an active front diffuser.
There are also openable cooling flaps in the front. They cause drag, so stay shut to keep drag down in slow-speed or very high-speed running. The 918 has five separate cooling circuits for the engine (oil), engine (water), gearbox (water-to-oil), electronics (water) and, because people and batteries are both comfy at the same temperature, a shared battery cooling and air-con system.
And the body? Carbon?
Oh yes. The tub and rear engine-and-suspension frame are made by the same people who build the McLaren tub - CarboTech in Austria. The Carrera GT had a similar tub, so Porsche has experience here. The engine frame is also carbon fibre, and the panels, and seat frames. Weight reduction is always a priority in fast-lapping cars but here it was extra-vital to offset the mass of the hybrid system.
The masses are where you want them, too. Everything of consequence is inside the wheelbase. The battery is extremely low and central. The engine and box are so low down that they had to mount the transmission upside down. (It's not a 911 transmission, by the way, because the extra torque and the mounting position meant every part had to change.)
Overall weight is 1634kg. Well, it is for the version with the Weissach pack: lightweight magnesium wheels, more visible carbon, a bit less soundproofing, fireproof seats instead of leather. This is the one whose figures I've been quoting - the 1674kg 'standard' car - is very slightly slower and less economical. Oh if you do see a 918, you'll know it has the Weissach pack by the aero-blades behind the rear wheel-arches. Those plus the lighter weight are what helped squeeze the 'Ring time under seven minutes. The standard car has more soundproofing, the nice show-car wheels and a price of £654,600. That makes it a £60k option price for the Weissach pack.
Any fancy chassis tech?
Well, the Carrera GT had pushrod suspension like an F1 car, but with all the electrical stuff in the 918 it wasn't possible to package it. There are adaptive dampers, with a sport position, but you probably won't use that mode except on very smooth tracks. They say it's too firm even for the Nurburgring.
We've mentioned the four-wheel-steering. It's similar to what's in the 911 GT3 and Turbo. The engineers say this makes a huge difference in making the car feel light and agile in slow bends (because the rears steer in opposite phase to the fronts), as well as stable at big speeds (when they go slightly same-phase). Certainly it feels like a very light, biddable car.
OK, the hypercar box seems pretty well ticked. What about the hybrid bit?
The 918 also has a conventional road-hybrid mode, the car switching between e-power and the V8 in pursuit of economy. Of course this isn't like a Panamera with a quiet V6: the noise of the strident V8 cutting in makes it a pretty unsubtle and clunky idea. No doubt it's working to an efficiency-maximising strategy, but from the driver's seat it arrive and disappears again on a quasi-random basis.
Hit the E switch and you have a 4WD electric car, capable of about 15-20 miles in normal driving. And 0-62 in 6.2 seconds without the engine. But in e-mode the braking is inconsistent in the pedal weight and feel, both in initial bite and the final roll to a stop. You get used to it, but it takes a while to adapt.
Let's face it, unless they want to make a secret getaway from the scene of a misdemeanour, no-one's going to drive this car without the engine on. Can't say it often enough: the point of the electric power is to add performance. Just to do it without ghastly consumption.
So if it's 4WD and quiet in cities, is it a realistic proposition to use daily?
Again against the hypercar grain, yes it is. The visibility is good, the driving position comfortable. They've proved the windscreen wipers work at 214mph top speed. The whole car has been durability tested for two Le Mans distances at full-on track speed. You can put the targa panels in the front boot. (The targa, by the way, originally used 944 cabrio roof catches. They were among the few shared parts in the whole car, but then they got modified too.)
Even the navigation and comms system is brand new and highly bespoke. It uses a touch panels with swiping gestures, with an additional colour panel above the lovely flying console. The graphics are lovely and the responses pretty quick, though the touch switches are a bit too touchy and I kept activating the wrong thing with a misplaced brush of a finger or sleeve. And it's connected to a concert-level Burmester 600W hi-fi.
So, in conclusion?
The 918 an astounding technical achievement. An absolutely all-new car, using bleedin'-edge techniques wherever you look. And it was done at record speed, apparently to Porsche's usual elevated quality. The engineers can't have slept a wink these past three years.
They've absolutely met the goals. The 918 is insanely fast, in a straight line and around a track. It's a car that looks after you rather than insisting that you're as good as it is. And you can use it every day. In that sense it's the 911 Turbo of hypercars, rather than a true successor to the Carrera GT.
So is it £800k-worth of raw excitement? Possibly not. To cover all the bases you're going to need a McLaren P1 and one of these. Well, you didn't come here for money-saving tips did you?