With the P1's launch getting closer McLaren has revealed details of the mid-mounted powerplant. A twin-turbo, 3.8-litre V8 petrol engine is combined with a lightweight electric motor for a total of 916hp. The combination is said to provide the responsiveness of a naturally aspirated engine thanks to its Instant Power Assist System (IPAS). In addition the P1 can travel six miles in electric mode and emits less than 200g of CO2 per km.
A new version of the V8 used in the MP4-12C is fitted to the P1, with a new block and other improvements to stand up to the extra load of the increased power output. There is now 737hp produced at 7,500rpm and maximum torque is 720Nm at 4,000rpm - 112hp and 120Nm up on the 12C. The electric motor was developed by McLaren Electronics and produces 179hp. When IPAS is activated this power can be deployed almost instantly.
Drive is transmitted through a seven-speed, dual-clutch gearbox. By applying negative torque to the engine the electric motor is used to achieve faster shifts by helping to reduce engine speed on upward gear changes. The electric motor also provides energy recovery, charging the battery when the driver comes off the throttle.
The battery can also be charged from mains electricity, with a full charge taking two hours. Weighing 96kg the battery pack is mounted on the under body of the carbon fibre chassis. A cooling system is fitted to manage the system's temperature for optimum performance and reliability.
Steering wheel mounted buttons control IPAS and the Drag Reduction System (DRS). The DRS alters the angle of the P1's rear wing, cutting drag by 23%. Releasing the DRS button or touching the brakes returns the wing to its normal position.
More announcements about the McLaren P1 will be made before it appears at the Geneva Motor Show on 5th March.
John Lambert - 21 Feb 2013
