Formula 1-derived DRS (Drag Reduction System) and IPAS (Instant Power Assist System) technologies offer an increase in straight-line speed and an instant boost of power.

The 3.8-liter twin-turbo V8 gasoline engine in the McLaren P1 is a new version of the M838T unit—developed in collaboration with Ricardo for the MP4- 12C supercar—significantly upgraded to optimize cooling and durability under its higher loads. The engine block has a unique casting to incorporate the electric motor.

The gasoline engine produces 727 bhp (542 kW) at 7,500 rpm, and 720 N·m (531 lb-ft) of torque from 4,000 rpm. (The M838T engine delivers 592 bhp / 441 kW at 7,500 rpm with 600 N·m at 3,000 rpm.) To optimize efficiency of the new gasoline engine, extensive testing and development work was carried out with McLaren Automotive technology partner Mobil 1 on lubrication and hydraulic fluids.

The lightweight electric motor, developed by the McLaren Electronics arm of the Group, produces 176 bhp (131 kW), and is unique to the McLaren P1. The motor produces maximum torque of 260 N·m (192 lb-ft). The combined torque of 900 N·m is delivered from 4,000 rpm.

In addition to this, the McLaren-developed boost system, IPAS, provides up to 176 bhp instantly. The instant response of the electric motor provides a sharper throttle response more associated with a normally aspirated engine, and the significantly enhanced air-charging system enables the McLaren P1 to have more top-end power.

The electric motor is mounted directly onto the engine, and all drive is channelled through the dual-clutch seven-speed gearbox to drive the rear wheels.

The e-motor can also provide faster upshifts. This is achieved through the application of instant negative torque at the point of shift, making the engine revs drop as quickly and efficiently as possible to the required engine speed for the upshift.

When off-throttle, the electric motor provides additional drag torque, recovering energy to the battery that would otherwise be lost to the brakes.

The McLaren P1 can be driven in a variety of modes, powered by the engine and electric motor together, or solely by the electric motor. E-mode is the most economical mode available with zero tailpipe emissions. In E-mode, the McLaren P1 can travel more than 10km with electric-only power; when the battery is depleted, the gasoline engine will automatically start to maintain drive and charge the battery.

IPAS and DRS. The power available via the gasoline engine and electric motor is further enhanced on the McLaren P1 through two steering wheel-mounted buttons which activate the DRS and IPAS.

The Drag Reduction System used on the McLaren P1 is a technology similar to that employed on Formula 1 cars. Speed is increased by reducing the amount of drag on the rear wing and, where the MP4-28 has a moveable flap on the rear wing, the McLaren P1 has a wing that reduces in angle to lower drag by 23%. The system immediately deactivates when the button is released, or if the driver touches the brake pedal.

IPAS is designed to deliver power rapidly for high performance acceleration, and provides 176 bhp of instant additional power. In developing the IPAS technology for the McLaren P1, power delivery was prioritized over energy storage. This is achieved through a lightweight battery pack, which offers greater power density than any other automotive battery pack on sale today, the company said.

Battery. The high power density has been achieved through a combination of high power cells, low pack weight and an innovative cooling system. The battery weighs 96 kg (212 lbs), and is mounted onto the underbody of the high-strength Formula 1-grade carbon fibre MonoCage chassis, which seals the unit in the vehicle, thus avoiding the added weight of any unnecessary battery packaging.

The coolant flow is balanced so each cell is cooled to the same temperature across the entire pack.

In addition to the battery being charged via the engine, the McLaren P1 is also equipped with a plug-in charger which can fully recharge the battery in two hours. The plug-in charger can be stored in the luggage compartment, although the customer may choose to store it off-board to save weight.

Further details of the McLaren P1 will be released prior to its debut.