Riding Shotgun in the 2015 McLaren P1

For most of the day, we've watched McLaren P1 test driver Phil Quaife turn in remarkably consistent lap times around Willow Springs International Raceway. The Californian desert circuit is 2.5 miles of banked bends, bumpy asphalt and broken curbs. There isn't much to hit, but any mistake will result in a bodywork-damaging trip into the rough, sandy scrub at the track's edge.

I love circuits like this. There's a sun-bleached charm to the venue, which was first used 60 years ago. Earlier, in the circuit office, I spied a list of track lap records, which shows that in February 1982 Nigel Mansell posted a lap time of 1 minute, 6.3 seconds, which equates to an average speed of 136 mph. For a few moments I quietly contemplate what level of bravery and commitment it would have taken to lap at that pace in a brutal, stiffly sprung, early '80s Formula 1 car.

Can the 2015 McLaren P1 Take the Heat?
McLaren's test today is not about records. The main objective has been to simulate how the hybrid P1 will behave when it is taken onto a track by one of the 375 well-heeled connoisseurs who will own one. The 903-horsepower P1 is designed to be the world's best driver's car, equally at home on the road or track, so it is natural that an enthusiastic owner might want to engage its full-fat "Race" mode on a circuit.

Back at McLaren's headquarters in the U.K., the development team simulated what might happen to the P1 after a dozen fast laps without a cooling-down period. Today, McLaren is using this test at a hot, sunny track to check that its calculations were correct.

Quaife, instructed to drive at a set pace for data-gathering purposes, has conscientiously done so lap after lap. With the test team satisfied and the track curfew fast approaching, there's just enough time for him to cut loose and exploit more of the P1's prodigious power and 664 pound-feet of torque. Unfortunately for the 27-year-old, he now has to contend with a considerable amount of extra ballast in the shape of me.

Yes, This Is a $1M Prototype
It's early July and although McLaren's engineers are moving into the final phases of the hybrid supercar's development, few outsiders have been allowed to ride in any of the prototypes. This car, code-named XP7, is one of several preproduction versions being used to validate the reams of simulation data generated during the car's development.

As much as I'd love to drive the 2015 McLaren P1, I'm secretly glad that the opportunity isn't on offer here. For three weeks the test team has been working from dawn until way past dusk to hone this car. Although their test in the U.S. is nearing an end, I don't think they would take too kindly to a nervous journalist bending their car. Besides, getting the chance to sit alongside one of McLaren's own testers — professional racer Quaife has been part of the development team for almost two years — is a real treat.

This well-traveled test mule is configured to collect heating, ventilation and air-conditioning (HVAC) data, so it is a little porkier than the 3,086-pound production car will be, and isn't equipped with the most up-to-date aero kit. Nevertheless, finished in a stealth bomber-spec black paint job and sitting quietly in the pit lane in the California sun, the taut, toned lines of the P1 make it look worth every penny of its $1.15 million price tag.

A Driving Mode To Suit Every Situation
Helmet on and seatbelts fastened, I survey the cabin, which is close to production spec. Looking beyond the data-gathering paraphernalia, some elements of the P1's interior are recognizable from the 12C, such as the center control interface and the turbine-style air vents, although everything is a lot more pared back.

Before we set off, Quaife points out some of the key controls, such as those for the drag reduction and instant power assist systems, placed within thumb's reach on the steering wheel. There's also a switch to toggle among the driving modes that are key to the P1's ability to fulfill its wide-reaching brief.

"The aim of this car is to be the best-handling sports car in the world, but we also want it to be very usable on road," says Quaife. "To combine those two elements is very challenging, as you can imagine.

"That's the beauty of our active panel, where you can switch through Normal, Sport, Track or Race modes. So we can go from Comfort on road, to turning up in the pit lane at a racetrack and switching to Race mode, where the car lowers, the wing comes up and it gives you more downforce.

"Also a nice touch is that we have different steering feel as you go up through the modes. In Normal mode the assistance is quite high for a car of this type. When you go into Race, it gets heavier, so you have more feel."

You Can't Possibly Prepare for the Thrust
With that, Quaife guns the P1 down the pit lane and on to the bumpy, dusty circuit. I'm shoved deeper into the bucket seat by a quite remarkable surge of acceleration. With 727 hp on tap from the 3.8-liter twin-turbo V8 and a supplementary 176 hp from the electric motor, I guess I should have been prepared, but I'm not sure you really can brace yourself for the kind of thrust that propels the car north of 60 mph in 3 seconds. Each time feels as much of an event as the first.

On track, the 2015 McLaren P1 is a steroidal, in-your-face monster. It will also make you revise any preconceived attitudes you may hold toward hybrid cars. It's noisy, with a hearty bellow from the twin-turbo V8 and a pleasing "whooomp" from its wastegates.

For me, the standout sensation is the level of grip. Turn 1 at Willow Springs, Castrol Corner, is a banked 90-degree left-hander. It dips and blends into a cambered right called the Rabbit's Ear, which goes on forever and involves at least two apexes.

The P1 is impossibly fast through this section. On our first flying lap I'm convinced that Quaife has carried too much speed into turn two and we're going to understeer wide into the scrub. My brain cannot compute that the car will keep on gripping, even with its bespoke Pirelli P Zero tires. But grip it does, without a hint of losing its composure.

Despite All the Grip, It Will Slide
In certain circumstances, the P1 can be made to break traction. Out of a tight, uphill left-hander, with the car travelling at a low speed, Quaife stabs the throttle and lets the back end slew pleasingly sideways for a millisecond. Then we swing downhill and left and on to the most spectacular turn on the circuit, the one where the effectiveness of the P1's aerodynamics package is truly evident.

Turn 6, Monroe Ridge, is a very quick right-hander over a crest which, from the low-slung vantage point of the P1's seats, is taken blind. Stray off the racing line here and there's a real danger of drifting wide off the circuit on the far side of the crest. But the McLaren is quite simply nailed to the ground.

The final section of the track involves two right-handers that blend together into one gradually tightening curve. It's a long turn, and the P1 feels comparatively docile through here. Quaife is waiting, waiting, waiting... then as soon as the pit straight looms into view, he squeezes the throttle and lets the car run wide out to the curb on the exit.

We zap across the line before the looming Castrol Corner demands heavy braking. The stopping power of the P1's brakes — developed by Akebono and using carbon-ceramic discs infused with ultra-tough silicon-carbide — is phenomenal.

A Supercar Designed for Less-Than-Super Drivers
I've ridden shotgun in World Rally Cars, a Dakar Rally truck and a Le Mans-winning sports car. All felt quick in a brutal way, but competition cars are designed with a single-minded purpose: winning, at all costs. As long as it succeeds, it doesn't matter whether a racecar's engine sounds like a bag of broken wrenches, or if the shut lines aren't millimeter-perfect.

The P1's purpose is different. To be simply fastest around a track is not enough; it must thrill all of its owner's senses and also provide the kind of creature comforts demanded by the well-heeled, no-compromise individuals who have already paid their deposits at the McLaren Technology Centre.

I'm interested to know why Quaife, an experienced campaigner in sports car and GT racing, changes his driving style at times and doesn't engage "maximum attack" mode during these track sessions in the P1 prototype. After all, isn't it important to test all the components and systems to their limits?

"Not everyone who buys the P1 will be a professional driver, so they might be a little bit more aggressive on the steering, the throttle pedal or the braking, and the car has got to cope with that," he says. Driving at different levels of aggression and pace also helps McLaren's test team calibrate the driver assist systems in the hypercar's different driving modes.

"When I'm driving smoothly around a circuit, for example, I don't have any interference from the ESP, but if it is being driven more aggressively and the car starts to move about a little bit more, the ESP needs to catch that slide without the driver knowing," says Quaife. "We want the systems working in the background, keeping the customer on his desired path but not feeling like the car is taking over."

My fleeting laps alongside a man who already knows the P1 inside-out suggest it is a car that's more rewarding to drive the more you push. There's so much to play with — F1-style power and aero boosts, a surfeit of low-end acceleration and reassuring levels of high-speed grip, to name a few — that an owner could grow with the car, gradually exploiting more of its potential as they become comfortable with the immense performance on tap.

We just have to hope that most of those 375 enthusiasts who are fortunate enough to afford the $1.15 million hypercar don't lock their cars away in a private collection.

The 2015 McLaren P1 is a machine that's made to be driven, and driven hard.

This content has appeared in Autocar and is reproduced with permission.