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We recently had the opportunity to participate in a technical workshop hosted by McLaren to discuss all things P1. The long-awaited successor to the famed F1 has been touted by the Woking-based operation as "the world's best car on road and track." So we took the opportunity to discover what will make this $1.15-million hypercar just that and compiled 10 pieces of information you probably didn't know—and, frankly, neither did we—about the P1. 1. The P1 Really is the P12 McLaren's first road car, the F1, was codenamed "P1." And that got us wondering, "What's P2 through P11?" It's unclear what P2 through P6 were, as McLaren says they were lost to time. (We suspect the Woking crew is keeping the details secret, for now.) P7 was the Mercedes-Benz SLR McLaren. P8 was an aborted Mercedes/McLaren follow-up project to the SLR. P9 and P10 were, well, these are some other projects McLaren is keeping secret, although we suspect they were other joint ventures with Benz. P11 is the 12C and its variants. So we are up to P12, which is the P1. P13 likely is the 911 fighter we're expecting, and P14 is on its way, too. We're not sure what form the P14 will take, but we've confirmed it won't be a sedan or an SUV. Phew. 2. Suspended Animation In the planning process it was deemed the suspension of the P1, or as McLaren calls it, "the world's best car on road and track," needs to adapt from casual drive to race-car focus at the touch of a button. The target roll stiffness is achievable with the hydraulic system underpinning the 12C. Controlling suspension heave, the up-and-down control of each axle, to the targeted level required something else. In the 12C, a Z-bar is fitted to control rear-axle heave. Heave is very important in a car like the P1 because at 150 mph it makes 1323 pounds of downforce. At that speed, even the smallest change in ride height will greatly affect aerodynamics and potentially upset the car's balance. Also, McLaren wanted the ability to slam the P1 2.2 inches closer to the ground. So, what is McLaren to do? File a patent, of course. While the hardware is supplied by Tenneco, the hydraulic actuators (that look like a fancy damper) now feature four chambers, instead of two in the 12C's hardware. The two extra chambers dictate ride height and control heave. Four additional accumulators (two at each axle) link the axles together. As in the 12C, the P1 is fitted with unequal-length control arms at the front at rear axles and relatively soft Eibach coil springs are at each corner. In the end, there are no anti-roll bars, no Z-bar, and eight hydraulic accumulators (there are four in the 12C).  The P1′s hydraulic actuators feature four champers, twice as many as are found in the 12C's actuators. 3. A 90-Percent New Powerplant McLaren looked at 10- and 12-cylinder options for the P1, but in the end, it determined that modifying the 12C's V-8 was the best choice, both for efficiency, packaging, and emissions, that target is 200 grams-per-kilometer, about one-third of the Bugatti Veyron's. While this 3.8 shares bore centers and cylinder dimensions with the 12C's, almost everything else is different. The aluminum block is beefed up so the electric motor can mount to its flank and handle the forces associated with said motor. The cylinder heads, pistons, fuel delivery, and turbochargers are all new. McLaren estimates the engine is 90-percent new. Maximum boost is up 40 percent to 20.3 psi. The transmission is closer to the 12C's unit, though, but, like the V-8, it's beefed up to handle more torque. When this engine is running its hottest—1796 degrees at the turbo, 1652 at the exhaust exit—the port injectors will continue to pump fuel into the cylinders when the driver lifts off the throttle. Unburned gasoline has a cooling effect on the turbo system, though once it hits the catalytic convertors, the fuel ignites and fire belches out the rear. Another interesting note: If the 12C's V-8 were in the P1, the airbox would sit completely outside the P1's skin. 4. It's Always On The 177-hp electric motor is linked to the drivetrain via a narrow gearbox between the 3.8-liter V-8 and dual-clutch gearbox. This gearbox has a fixed ratio of 2.02:1 and it is how McLaren managed to line up the torque and power peaks of the V-8 and electric motor. There is also a clutch between the motor's gearbox and the engine, so the P1 can, and will, drive under electric power. In fact, there is no way to drive the P1 without some torque from the electric motor going to the wheels. And, with 177 horsepower on tap, the electric motor can power the car at speeds of more than 100 mph all by itself. 5. A Carbon-Fiber Cage To transform the 12C's carbon-fiber tub into the P1's MonoCage, McLaren utilizes a process it calls co-curing. It combines resin transfer molding and an autoclave. The lower half of the MonoCage is, for all intents and purposes, the same as the tub found in the 12C, although it's about 11 pounds lighter. Then the roof is laid up on the tub and the top half is cured in an autoclave. The end product weighs less than 200 pounds. And, while we're on the topic of carbon fiber, the front clamshell weighs about eight pounds and the rear clam, that stands six feet tall, is about 15 pounds. McLaren claims the P1 will come in at around 3100 pounds, but we suspect the actual curb weight will be closer to 3300 when she's full of fluids.
6. Very, Very Cool Gobs of power, 903 ponies to be exact, means lots of heat. To manage all that heat McLaren employs 13 heat exchangers. Yes, that is a lot. McLaren estimates the P1′s V-8 generates 20 percent more heat than the 12C's, and thus requires about 40 percent larger radiators. 7. More on the Way McLaren promises a new model in each of the next two years. It's unlikely the 2014 model will be the 911 fighter. We're thinking the '14 model will be a track-oriented 12C variant. Maybe P1's 727-hp V-8, sans electric motor, will power such a car. 8. A Natural Feel P1 planners and engineers didn't think they could adapt an existing electrically assisted steering rack to provide ample feedback. Instead, and as is the case in the 12C, an electrohydraulic system is used. This pump also moves hydraulic fluid around the suspension system. Brakes, too, were a feedback concern. While most hybrids use the electric motor(s) to slow a car with regenerative braking, the P1 harvests the otherwise wasted energy generated by the engine during off-throttle events, like coasting, in order to preserve brake feel.
9. Start Me Up The 177-hp electric motor has many roles. Aside from delivering torque to the wheels, it starts the V-8, charges both the high voltage (535-volt, 4.7-kWh hybrid battery), and via a DC-DC convertor, acts as an alternator by managing the standard 12-volt system. This setup simplifies the engine auxiliary layout. In fact, the engine lacks any belt-driven auxiliary altogether. Aside from the motor, there is an A/C compressor, but it is driven off the electric motor's gearbox. 10. Suppliers Many suppliers and partners were tapped for this project. Here are just a few: Carbo Tech GmbH worked on the MonoCage, Tenneco was involved with the hydraulic suspensions, Eibach supply the springs, Ricardo had a hand in the engine, Axeon handled the battery pack, the transmission is a Graziano, seats come from Sabelt, Prodrive constructed the body, Akibono developed the brakes, and the electric motor is all McLaren. from Car and Driver Blog http://blog.caranddriver.com | |||
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Monday, May 13, 2013
Ten Things You Probably Didn’t Know—And Neither Did We—About McLaren’s P1
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