The astonishing McLaren P1™, which debuted in production form in March 2013 at the Geneva Motor Show, had a clear goal – to be the best driver’s car in the world on road and track. To achieve this objective, McLaren used all its 50 years of racing experience and success, especially in the fields of aerodynamics and lightweight carbon fibre technology.
The result was a car with an unprecedented amount of downforce for a road vehicle; levels similar to a GT3 racing car and yet with even greater ground effect. This downforce not only boosts cornering and braking performance, it also helps balance, stability and driveability at all speeds.
McLaren introduced the carbon fibre chassis to the world of Formula 1 in 1981 with the MP4/1, and had the first carbon-bodied road car in the McLaren F1. Always at the forefront of vehicle aerodynamics, McLaren raised the supercar performance bar in the 1990s with the F1; with the McLaren P1™, it redefined it once again.
To live up to its design brief of being the best driver’s car in the world, the McLaren P1™ had to have exceptional straight-line performance and instant throttle response. To deliver this, it uses an innovative IPAS petrol-electric powertrain comprising a McLaren 3.8-litre twin-turbo V8 petrol engine, coupled to a single electric motor. Collectively known as M838TQ, the combined power output is 916PS (903bhp). As important as absolute power is the electric motor’s ability to provide instant torque, making the powertrain superbly responsive. It is also amazingly efficient. The McLaren P1™ returns 34.0mpg (8.3 l/100km) on the EU combined cycle, with CO2 emissions of 194 g/km. The electric motor offers a range of more than 10km (6.8 miles) in full electric mode on the NEDC cycle, with emissions dropping to zero.
Maximum speed is electronically limited to 350km/h (217mph), with 0-100km/h (62mph) standing start acceleration taking just 2.8 seconds. The McLaren P1™ will power from rest to 200km/h in 6.8 seconds, and on to 300km/h in 16.5 seconds – a full 5.5 seconds quicker than the McLaren F1.
The braking figures for the McLaren P1™ are equally as impressive, a bespoke Akebono system with specially formulated, carbon ceramic discs coated in silicon carbide able to bring the McLaren P1™ to a halt from 100km/h (62mph) in just 30.2 metres.
The advanced technologies developed for the McLaren P1™ included active aerodynamics and adjustable suspension – both banned in Formula 1 by 2013, due to being seen to give too great a performance advantage. Airflow is optimised around the body using an active wing and underbody devices; the adjustable rear wing can extend from the bodywork by 120mm on road and up to 300mm on the race track, maximising downforce. The wing is directly inspired by Formula 1 design, with the intersection of the double element rear wing and design of the endplates being the same as that on the 2008 championship winning McLaren MP4-23.
In addition, the McLaren P1™ also features adjustable ride height as part of its hydro-pneumatic suspension. The RaceActive Chassis Control (RCC) can lower the car by 50mm in Race mode, to produce ground effect aerodynamics. It also features adaptive spring rates, roll control, pitch control and damping, all providing a huge range of adjustment, making the McLaren P1™ perfect for either road or track. In Race mode, the spring rates stiffen by 300 per cent, allowing the McLaren P1™ to corner at more than 2g.
Formula 1-inspired technology permeates the McLaren P1™. The revolutionary carbon fibre MonoCage monocoque forms a complete structure that incorporates the vehicle’s roof and distinctive ‘snorkel’ air intake – a styling feature inspired by the McLaren F1 road car.
McLaren is an acknowledged world leader in carbon fibre technology. The material offers lightness, strength and rigidity – improving performance, safety, handling, agility, durability, efficiency and ride comfort. The body panels of the McLaren P1™ are made from lightweight yet strong carbon composite, with their complex shapes tuned for optimal aerodynamics.
The McLaren P1™ was designed from the outset to prioritise aerodynamic performance – just like a Formula 1 car. As with a Formula 1 car, wind tunnel testing and CFD (computational fluid dynamics) aerodynamic modelling were used to optimise the aerodynamic flow for both incredible levels of downforce powertrain cooling. The resulting 600kg of downforce in Race mode at well below maximum speed (257km/h / 161mph) is considerably higher than most other comparable high performance supercars and in line with the levels of downforce generated by a GT3 racing car of the same era. This downforce improves cornering ability, especially in high speed corners, and the overall balance, agility and controllability of the McLaren P1™ are all outstanding.
Other areas of Formula 1 technology evident on the McLaren P1™ include the highly efficient IPAS (Instant Power Assist System) which is a development of the KERS (Kinetic Energy Recovery System) used on Formula 1 cars, while DRS (Drag Reduction System) is also used on the McLaren P1™, giving extra power and straight-line speed both at the touch of a button. The car is equipped with revolutionary layered carbon ceramic brakes developed for the road by Akebono, as well as Brake Steer – another outlawed Formula 1 technology that improves cornering behaviour and increases cornering speed.
The name of the McLaren P1™ is itself inspired by Formula 1, ‘P1’ referring to ‘first place’ or ‘position one’. There is also a heritage link: the McLaren F1 was initially known internally within McLaren as Project 1, or simply, P1.
The McLaren P1™ was designed to be driven to a racing circuit as a refined and comfortable high-speed supercar, before being used on the circuit to offer an experience matched only by purpose-built race cars. Those fortunate enough to secure ownership of a McLaren P1™ joined an exclusive club, McLaren having kept production to the 375 road cars that it announced when the car was launched.
The McLaren P1™ is very much an engineering-led design, as is the McLaren way. Form follows function. Nothing is superfluous. Everything is designed for a reason, as with a Formula 1 car.
The mid-engine, two-seater design reflects the aerodynamic requirements needed to meet the ambitious downforce targets for the McLaren P1™. But there was also clearly a desire to make a very beautiful and striking ‘supersports’ car.
“The McLaren P1™ reflects the McLaren brand’s core values. It celebrates aerodynamics, great packaging and light weight, and is all about innovative technology. At the very beginning, we sought to develop a car that you could drive to a racing circuit, then press a button and race it. The priority was high-speed performance matched with tremendous composure, which would come mostly from the state-of-the-art aerodynamics. We wanted a car that was connected and predictable at any speed.’”
Dan Parry-Williams, Design Engineering Director, McLaren Automotive
The design team worked to a brief of ‘light and agile’. The design had to be ‘shrink wrapped’ around the mechanicals, making the car as compact and lightweight as possible. There are only five main panels: front clamshell, front bonnet, rear clamshell and the doors, all made from lightweight carbon fibre. The strong carbon construction means the panels can ‘multi-task’, acting both as aero-honed ducts and load-bearing supports. They are intricately shaped yet superbly finished, helped by their strong carbon construction.
The McLaren P1™ sits extremely low (1,138mm height in Race mode) with a smaller frontal area than any other comparable series production super sports car. Cd is just 0.34, which is very low considering the enormous levels of downforce possible.
The car is also fitted with a vehicle lift system, which raises the height of the vehicle 30mm front and rear. This increases the approach and departure angles, and ground clearance is optimised to aid manoeuvrability over ramps and uneven surfaces. The system will remain in the raised state at speeds of up to 60km/h. If this speed is exceeded, the McLaren P1™ will return to its normal ride height.
The incredibly low rear and pronounced rear haunches highlight the ‘shrink-wrapped’ design and efficient packaging. Importantly, the design gives superb airflow to the large adjustable rear wing. The shape of the whole body – and the sculpted doors in particular – is clearly shaped by the path of the air flowing over and around the car.
The design concept, including the low rear deck, rear wing, inlets and outlets and the teardrop-shaped glass canopy, was initially produced as a three-dimensional surface model by McLaren Automotive Design Engineering Director, Dan Parry-Williams, and his team, who defined all the critical packaging and aerodynamic requirements as an evolution of contemporary Le Mans race car principles.
The preliminary surfaces were developed and refined through the Concept Design process to create the final styled shape, while still respecting all the aerodynamic, cooling, packaging and manufacturing requirements. During this phase, details of systems such as the roof snorkel engine air intake, radiator air intake systems, front underbody aerodynamics, low-temperature cooling system and engine bay cooling were all worked out in detail. This involved extremely intensive detail engineering design and aerodynamic CFD simulation for aero efficiency and cooling.
An early mule prototype was built during this phase to prove out the simulation results, while the design was still fluid. Developing the design to this point before the styling process was essential in achieving the incredible compactness, aerodynamic performance and overall design integrity that the McLaren P1™ project demanded.
Against the backdrop of the engineering priority being unmatched aerodynamic performance, the design team was challenged to deliver a dramatic and genuinely beautiful car that was very much a ‘statement of intent’ in keeping with the heritage of McLaren, but also at the forefront of automotive design. The decisions to adopt elements of a Le Mans race car – the low body, long rear deck and open mesh rear styling that both showcases the mechanicals and helps cooling, together with a rear diffuser that is one of the most aggressive ever seen on a road car – were taken very early in the programme. The resulting design was instantly memorable, but the reasoning goes well beyond styling: like everything on the McLaren P1™, the features are there for a good reason.
Fighter jet canopy
The glasshouse on the McLaren P1™ was inspired by the canopy of a fighter jet, with a notably low cowl and a windscreen that is deeper than it is wide. In combination with the two glass, solar-reflecting panels above the cockpit, these attributes give the cabin an incredibly light and airy feeling and ensure good visibility – always a McLaren mantra. The teardrop-shaped canopy also optimises the flow of air to the rear wing.
The ‘hammerhead’ style nose looks dramatic, giving the car a low and wide stance, but also serves an important functional purpose: the design directs airflow to two front mounted, low-temperature radiators that cool both the petrol engine’s turbocharged air and the IPAS powertrain’s electrical system.
The narrow LED headlamps, shaped in the style of the McLaren ‘speed marque’ logo, give superb illumination but are also very space efficient, optimising the frontal area that can be used for cooling. The distinctive shape of the bonnet vents is entirely dictated by function, the apertures directing hot air exiting the front radiators over the top of the roof, leaving a channel of clean, cold air to feed the roof-mounted engine intake snorkel. The hot air that flows over the roof of the car is kept away from the car’s flanks to ensure fresh air is ingested by the main side-mounted radiators and helps to boost downforce.
At the rear, the LED lights are invisible by day but offer attractive and ultra-thin strips of light at night. The lights are as thin as possible to maximize the rear surface area that allows hot air to escape. This signature rear graphic, which highlights the very edge of the bodywork, was inspired by sports prototype racers and is in keeping with the fact that the rear of the car is entirely open to aid cooling and to extract turbulent air from the rear wheel arches to help aerodynamic flow.
Inspired by the McLaren F1 and Formula 1
Two cars from the history of the McLaren brand are cited as being the inspiration for the overall design of the McLaren P1™: the iconic McLaren F1 road car of 1993, and Lewis Hamilton’s championship-winning 2008 Formula 1 car, the MP4-23.
The 2008 Formula 1 season was the final year that cars were allowed to race with a full suite of aerodynamic aids. The design team scrutinised every element of the MP4-23, a car that was styled to be functional rather than beautiful but is recognised nonetheless for its dramatic beauty. The influence that scoops and slats had on the style and the fact that every duct and every surface of the MP4-23 does a job, either in aero or cooling, was not lost on the designers of the McLaren P1™.
The design team paid homage to the McLaren F1 road car, but did not try to imitate it. The side greenhouse graphic of the two cars is similar, especially the rear three quarter window, as are the signature McLaren dihedral doors, the low front cowl and the side swage lines. The roof snorkel, which forms part of the carbon fibre MonoCage, is effectively carried over from the F1.
The dihedral doors of the McLaren P1™ are instrumental in the car’s astonishing aerodynamic performance. Their complex shape helps channel clean air to the side mounted radiators and also cuts the turbulence normally experienced along the side of a car. Their scalloped form is in line with an overall philosophy of ‘pushing in’ surfaces to create an almost ‘exoskeleton’ approach, with no ‘fat’ between the mechanicals of the car and the skin.
The final design
Following the preview of the McLaren P1™ as a design study at the Paris International Motor Show in the autumn of 2012, McLaren actively engaged with potential customers to understand their views of the styling. The unanimous verdict was not to change the car presented in Paris and the McLaren P1™ debuted as a production car in March 2013 at the Geneva International Motor Show with just one significant visible change, namely the addition of LTR ducts ahead of each of the front wheels to further aid cooling and optimise downforce.
At the launch of the McLaren P1™, McLaren confirmed that to maintain exclusivity it would produce just 375 examples of the car.
The McLaren P1™ is a groundbreaking car because of the technology and performance it offers, but it also optimises the emotions felt by the driver; through sensory enhancements, the driver feels a part of the car and more connected to the road as a result.
“When you drive the McLaren P1™, your senses are stimulated. The primary touchpoints for the driver– the steering and pedal feel – have been optimised to give the greatest level of feedback, and make the driver feel truly connected to what is going on with the car. And this emotional involvement increases as you work through the different modes – E-mode, Normal, Sport, Track and Race – with a real crescendo for the senses in the fully track-focused Race mode. You really do feel part of the car.”
Dan Parry-Williams, Design Engineering Director, McLaren Automotive
Throttle, steering and braking
The throttle of the McLaren P1™ is tuned and calibrated to provide the same levels of responsiveness in each gear, under very small inputs. There are seven individual throttle calibrations, which means that during both acceleration and deceleration a constant rhythm is guaranteed for all gearchanges.
The accelerator pedal feel is calibrated to ensure consistent feel in every gear, both in IPAS drive mode when the full 916PS (903bhp) is available and also when the steering wheel-mounted IPAS Boost button is pressed. This feature gives a consistent, instantaneous throttle response, no matter which mode the car is running in.
The steering feel of the McLaren P1™ is optimised to ensure that the driver feels directly connected to what is happening with the wheels and the road. Finely tuned steering geometry and a steering ratio of just 2.2 turns lock-to-lock, enhance steering feel and the dynamic responsiveness of the car.
The ‘feel’ through the brake pedal is also refined to give improved feedback and a greater feeling of connection with the wheels. The braking system is very progressive, allowing the driver to modulate the brakes more easily and giving an intuitive brake feel that is more akin to a racing car.
McLaren is a global pioneer in carbon fibre technology. It introduced the first carbon Formula 1 car (the MP4/1 in 1981), the world’s first all-carbon-bodied road car (the F1, of 1993), and today it makes more carbon road cars than any other manufacturer. It is the perfect material for strength, light weight, rigidity and durability, so unsurprisingly the McLaren P1™ has a carbon fibre monocoque, carbon fibre body panels and a carbon fibre interior.
Lightweight MonoCage carbon tub incorporates roof structure
The McLaren P1™ is built around a carbon tub with an upper structure that incorporates the vehicle’s roof and distinctive snorkel air intake. This ‘MonoCage’ is a light yet immensely rigid structure to which the main components are fixed and in which the IPAS battery and power electronics are housed. Weighing just 90kg, the MonoCage meets full FIA loads and all relevant crash requirements to provide a protective cell for occupants.
A combination of Formula 1 style pre-preg autoclave technology and precision resin transfer moulding (RTM) achieves the single piece construction. Every element of the composite raw material used on the McLaren P1™ MonoCage and carbon body is bespoke and engineered specifically to suit the extreme performance and weight requirements of the McLaren P1™, as well as the unique manufacturing technology employed.
The Formula 1-style carbon material includes fibres with stiffness modulus as high as 5000GPa (more than twice the stiffness of steel), fibres with strength greater than 6000MPa (more than five times the strength of the best grade titanium) and also includes the use of Kevlar fibres.
The high-technology tub gives numerous dynamic benefits: occupant safety is improved; the light weight improves performance and reduces emissions; agility is enhanced and the high torsional rigidity ensures accurate suspension geometry, boosting ride and handling performance.
Pre-preg, Formula 1-style carbon was specified for all the body panels. The panels, which are complex in shape to incorporate cooling ducts and aero surfacing, needed to be very strong but also very light.
“Each moulding was designed to do as many jobs as possible, meaning fewer parts and less weight; we followed the Colin Chapman diktat that ‘nothing is as light as nothing’, ruthlessly removing unnecessary components.”
Dan Parry-Williams, Design Engineering Director, McLaren Automotive
Strong yet very light carbon body panels
The front and rear clamshells are large, single piece mouldings that are light enough to be effortlessly picked up by hand. The front clamshell includes the moulded luggage bin, which offers 120 litres of storage. The rear clamshell is fixed; it only comes off during servicing. Two service flaps, just behind the roof, give access to fuel filler, oil, High Power Density (HPD) battery charger socket and coolant. The wheel arch liners – also made from pre-preg carbon fibre – double as air intake ducts and mountings for the HPD, the IPAS battery, charge air coolers and oil coolers and the clutch.
The McLaren P1™ has no floor carpet as standard – it is unnecessarily heavy – and no sound deadening. Even the glass has been re-engineered to reduce weight; the windscreen is only 3.2mm thick, including a plastic interlayer, and is 3.5kg lighter than a ‘normal’ screen. The super lightweight glass used in the roof has been chemically toughened, and is only 2.4mm thick.
A powerful yet highly fuel-efficient powertrain that offered superb throttle response was clearly essential if the McLaren P1™ was to be faster around a racing circuit than any other production road car and the design team quickly deduced that the best all-round solution would be a hybrid petrol-electric engine. Providing extreme levels of power, instant torque and very impressive fuel efficiency and CO2 figures, the resulting powertrain feels akin to a very strong, normally aspirated engine.
The twin-turbo petrol V8 and single electric motor – both mounted behind the cockpit in a mid-engined position – have a combined output of 916PS (903bhp) and 900Nm, with emissions of 194g/km. Power is driven to the rear wheels through a seven-speed, dual clutch gearbox. The McLaren P1™ can be driven in three propulsion modes: using the petrol engine, powered solely by the electric motor, or using a combination of the two.
Maximum power comes when using both engines together, but even in E-mode the performance is strong. In IPAS (Instant Power Assist System) mode, the battery is recharged using surplus energy from the petrol engine. Developed by McLaren, IPAS can provide up to 179PS (176bhp) from the electric motor in the McLaren P1™, deployed at the touch of a steering wheel-mounted button.
The 3.8-litre twin-turbo V8 in the McLaren P1™ is a version of the McLaren M838T petrol engine. The McLaren P1™ engine block has a unique casting which incorporates the electric motor and also provides increased stiffness. The unit is fitted with a bespoke pressure charging system to optimise cooling and durability under the higher loads. Dry sump lubrication and a low-sited, flat plane crankshaft to lower the centre of gravity also feature. The water-cooled and oil lubricated turbochargers run at 2.4 bar.
The McLaren P1™ petrol engine produces 737PS (727bhp) at 7,300rpm, with torque of 720Nm from 4,000rpm.
Electric motor and instantaneous torque from IPAS
The single electric motor in the McLaren P1™ produces 179PS (176bhp) and 130Nm of torque – although as it is geared by a multiple of two, the effective torque output is 260Nm. Developed by the electronics arm of the McLaren Group, it is unique to McLaren P1™. Weighing 26kg, the motor produces more than double the power of the KERS units used in Formula 1 at the time the McLaren P1™ was launched (179PS versus 82PS).
The electric motor and 3.8-litre twin-turbo McLaren V8 petrol engine work seamlessly together, delivering very high maximum power. The additional power from the electric motor can be deployed through the IPAS button mounted on the steering wheel and delivers maximum torque instantly, greatly increasing throttle response of the McLaren P1™.
“The electric motor helps to provide extra torque anytime, anywhere, and comes in instantly. It makes a huge difference and fills in the holes in the torque curve that you often get with turbo engines just after gear shifts, when the turbos are responding.”
Chris Goodwin, Chief Test Driver, McLaren Automotive
The electric motor has internal rotor cooling – unusual for an automotive electric motor – that enables it to produce maximum performance for longer periods. An outer jacket is also used to further aid cooling of the electric motor.
The ground-breaking, lightweight battery pack in the McLaren P1™ offers greater continuous power density than any other car battery pack on sale when the car was introduced. McLaren prioritised power delivery over energy storage, designing the system to provide power rapidly for high performance acceleration. The additional power offered by the battery is accessible through pressing the steering wheel-mounted IPAS button and provides an electric range of more than 10 kilometres in the combined European drive cycle.
Direct braking kinetic energy regeneration is not employed – a decision taken to maintain a consistent feel during braking, which crucial for performance driving – but energy that would normally be wasted when lifting off the throttle is captured by the electric motor and harvested in the battery, especially in higher gears.
In addition to the battery being charged via the engine, the McLaren P1™ is equipped with a plug-in charger that can recharge the battery, from empty, in as little as 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.
The ‘Charge’ button on the fascia allows the driver to recharge the battery quickly, using the V8 engine as a generator, in preparation for electric-only use (to extend range) or for a hot lap of a track (where maximum additional electric power can be utilised).
The high power density has been achieved through a combination of ultra-high-power cells, low pack weight and an innovative cooling system. The battery weighs just 96kg, a crucial factor in optimising the performance of the McLaren P1™. Mounted between the cabin and engine bay for optimal weight distribution, the battery is housed within the high-strength carbon fibre MonoCage chassis, avoiding the added weight of battery packaging.
The battery has six modules, each of 54 cells (324 cells in total), and uses a Battery Management System (BMS) with active cell balancing, which can transfer charge from cell to cell to maintain accurate balance throughout the power pack and ensure optimum performance and durability. Due to the amount of power being supplied by the battery, complex cooling is required to guarantee cell performance and reliability; the coolant flow is balanced to ensure each cell is cooled to the same temperature across the entire pack and two extremely accurate and rapid safety-critical monitoring boards are fitted to each cell module, reporting on battery cooling, state of charge and battery health.
The electric motor is integrated into the 3.8-litre twin-turbo V8 petrol engine, and drives a dual-clutch, seven-speed gearbox. All drive – either in electric or IPAS mode – goes through the gearbox. As the electric motor can be decoupled from the petrol motor, the McLaren P1™ has, in effect, three clutches.
The gearbox is an uprated version of the seamless shift unit used in all McLaren cars. Additional cooling is required to manage the more powerful IPAS petrol-electric powertrain and two air-blast clutch coolers are also fitted, to optimise oil cooling.
Manual gear-shifting is by paddles mounted on a rocker behind the steering wheel. The carbon fibre paddles are optimised for weight-saving and are designed to allow ease of use whilst also operating the IPAS and DRS buttons.
The default for the McLaren P1™ transmission is fully-automatic mode, which is especially useful for city driving. The paddles can also be used to change gear while in automatic mode, and a fully manual gearchange can be selected via a button on the Active panel. In E-mode, the McLaren P1™ always drives in automatic.
The E-mode is the most economical mode available, with zero tailpipe emissions and almost silent running. Where possible the car will operate in electric-only power, but should there be insufficient battery power the petrol engine will automatically start. The E-mode makes the McLaren P1™ eligible to drive in towns or cities where restrictions on internal combustion-engined vehicles are in place.
In E-mode, the 10km-plus range is sufficient for most city journeys and in different circumstances the car is able to reach speeds in excess of 160km/h. When the battery is empty, the petrol engine will automatically start to maintain drive and charge the battery; performance remains the same as in electric-only drive, achieved through an ECU map that restricts performance to a level equivalent to that provided by the electric motor.
E-mode can be selected via the E-mode switch on the dashboard prior to switching on the ignition. If the car is already on the move, the powertrain will instantly change to electric power when the E-mode button is pressed.
Pushing the Charge button (next to the E-mode button) engages the petrol engine to quickly recharge the battery. If the vehicle is in E-mode, when the battery is fully recharged the petrol engine will stop automatically. Recharging the battery in this way takes just 10 minutes.
The manual gear-shift paddle have no effect in E-mode and the dynamic settings are the same as in Normal suspension mode; it is not possible to select other settings in the Active Dynamics Panel in E-mode.
IPAS petrol-electric mode
The default mode for the McLaren P1™ is in IPAS drive, when both petrol and electric motors operate in unison. Combined power is up to 916PS (903bhp) and maximum torque – limited to protect the clutch – is 900Nm.
The electric motor does far more than just add extra power and torque. The instant response of the electric motor provides sharper throttle reaction than is usually experienced in cars powered by petrol engines with large turbochargers. A further benefit of the electric motor is its ability to enable faster upshifts through the provision of negative torque to make engine revs drop as rapidly and efficiently as possible to the engine speed required for the upshift.
The combination of an electric motor and state-of-the-art pressure charging system gives the McLaren P1™ both sharper throttle response and more top-end power – the perfect recipe for high performance driving.
Unlike many other powertrains that use both petrol and electric power, the internal combustion engine of the McLaren P1™ is always active unless E-mode is selected – the car does not continuously cycle between drive modes. “We didn’t even try to do it,”’ says Dan Parry-Williams. “We felt that it would detract from the driving experience to have more unexpected engine starts than absolutely necessary; believe me, you’d notice if a 737PS petrol engine suddenly starts up behind you!”
At standstill, such as at traffic lights or a junction, the petrol engine will switch off automatically when the brake pedal is depressed, and restart again when released.
IPAS drive operates in Normal, Sport, Track and Race modes. In addition, the McLaren P1™ has a separate ‘Boost’ button located on the centre console, which diverts up to 179PS (176bhp) of power and 230Nm of torque from the electric motor through the steering wheel-mounted IPAS button.
The system operates only when close to full throttle and when pressed, the IPAS button deploys the full power and torque available. Unlike Formula 1, there is no time limit to IPAS activation in a single press; the amount of extra power and torque depends on the battery’s state of charge (SOC) and its operating temperature.
The McLaren P1™ also has a Launch mode, for maximum standing start acceleration. This can be operated in all powertrain settings except for E-mode. ESC (Electronic Stability Control) can only be deactivated in either Track or Race mode.
Outright performance is, unsurprisingly, astonishing. Top speed is electronically limited to 350km/h, and standing start acceleration figures are even more incredible: 0-100 km/h (62mph) in 2.8 seconds; 0-200km/h (124mph) in 6.8 seconds and 0-300km/h (186mph) in 16.5 seconds. By comparison, the McLaren F1 road car achieved 0-100km/h in 3.2 seconds, 0-200km/h in 9.4 seconds and 0-300km/h in 22 seconds.
When the Active panel is not switched on, powertrain and handling are both automatically set to the default Normal mode, and the car changes gear automatically. Pushing the Active button empowers the suite of high performance controls – including Sport and Track suspension and powertrain settings (activated by rotary switches beneath the Active button); IPAS and DRS (activated by steering wheel-mounted buttons); Launch mode (a button on the dash); manual gear change (push the Manual button) and the active aero and suspension settings.
The Active button must also be on before the Race mode can be engaged. When Race mode is selected, the car automatically lowers by 50mm and stiffens the suspension using hydraulic springs. This mode gives bespoke roll and damper settings, spring rates increasing by up to 300 per cent.
The Formula 1-style Inconel exhaust follows the most direct route from the engine out to the back of the car, minimising weight in line with design requirements for a system that weighs just 17kg in total.
The rear of the chassis was engineered to optimise the route taken by the exhaust pipe following the shortest course possible. By taking this action and keeping the exhaust low, the design team were able to keep the rear of the car extremely low. The angle of the exhaust exit has been optimised to match the angle of the rear of the car, helping to create downforce. Exhaust gases exit under the rear wing, creating an area of low pressure.
The McLaren P1™ was designed from the outset using a wind tunnel and CFD (computational fluid dynamics) aerodynamic tools – just like a Formula 1 car – by McLaren engineers experienced in the highest level of motorsport.
The aerodynamic performance produces incredible levels downforce – up to 600kg, which at the time that the McLaren P1™ was introduced was more than any other production road car to date.
“The levels of downforce produced actually makes driving easier as well as faster. As you build speed, you actually feel you have greater control as the levels of downforce increase the car’s grip on the track. Every panel, air intake, and air exhaust was designed to guide clean air into the ducts from the most efficient places and to maximise cooling; that’s partly why the body is so compact, and looks so ‘shrink-wrapped’. “
Dan Parry-Williams, Design Engineering Director, McLaren Automotive
The door ducts draw air into the cooling circuit and the low body helps air get to the rear wing as quickly and effectively as possible. The rear deck is extraordinarily low, just like a sports racing car and the extreme teardrop shape of the glasshouse guides more air more efficiently to the rear wing.
The 600kg of downforce is achieved in Race mode, when the car sits at its lowest ride height and has its rear wing fully extended. However, that level of downforce is achieved at 257km/h (161mph) which is well below maximum speed; this was a deliberate decision taken to optimise downforce for ‘real world’ track corners, which are unlikely to be encountered at 350km/h.
The downside of so much downforce at 257km/h is that, if the aerodynamics were fixed – rather than actively adjustable – the downforce would be so great at maximum speed that the suspension would have to be reinforced, adding weight for no benefit in track performance. This problem is overcome using active aerodynamics, the front and rear wings being trimmed to ‘spill’ downforce as speed increases over 257km/h.
Active aerodynamics – front and rear wings
The large rear wing sits flush with the rear bodywork when stowed, but adjusts automatically to boost downforce and optimise aerodynamics. It can extend by 120mm on the road and when Race mode is activated through the button on the fascia, by 300mm on a racetrack.
When deployed, the pitch of the wing also changes to optimise the levels of downforce, increasing by up to 29 degrees. The double element rear wing profile has been developed using the same methods and software employed for the McLaren MP4-28 Formula 1 car. The rear wing can provide a similar function to the Airbrake on other McLaren cars, but it is actually still working like an inverted aeroplane wing. The wing produces significantly higher levels of downforce on the rear of the car than the Airbrake system, ensuring the rear brakes work much more effectively. With the McLaren P1™ in Race mode, under braking the rear wing can offer up to three times the level of downforce generated by an Airbrake.
In addition to the adjustable ‘active’ rear wing, the aerodynamic performance of the McLaren P1™ is optimised using two flaps mounted under the body and ahead of the front wheels. These are also actively controlled and change angle automatically to optimise performance, downforce and aero efficiency, increasing both speed and grip. The flaps operate through a range of zero to 60 degrees.
The rear wing and front flaps work in conjunction with each other to maximise handling, braking and straight-line performance. The active aerodynamics ensures totally consistent handling and driving behaviour.
Ground effect suction
The underbody of the McLaren P1™ is smooth and like the body panels and MonoCage chassis, made from carbon fibre. This flat surface beneath the car also helps to generate ground effect suction, boosting downforce.
Every design detail optimises aerodynamics, from the door shape, which is designed to funnel air with maximum aero efficiency, to the numerous ducts, to the wheel-arch shapes to the snorkel intake on the roof. The latter detail was an iconic feature of the seminal McLaren F1 road car.
The variable ride height suspension lowers the car by 50mm in Race mode. This ‘squeezes’ the air flowing beneath the body, creating ground effect suction, planting the car to the road at higher speeds. The levels of aero performance put the McLaren P1™ ‘in a different league to other cars.
“Having raced Le Mans cars, I have a good handle on what they’re like and we’re up there in that ballpark with this car. In fact, in some ways we’re better, because we have more technical freedom. They have aerodynamic and suspension restrictions to adhere to, which we don’t have to work to with a road car. The astonishing thing about the McLaren P1™ is that it feels like a really fast ‘supersports’ car on the road – really fast – but it feels like a really good racing sports car on the track. I don’t think that’s ever been done before.”
Chris Goodwin, Chief Test Driver, McLaren Automotive
Rear wing with DRS
DRS, or Drag Reduction System, is a technology used in Formula 1 to deliver increased straight-line speed that also features on the McLaren P1™. Speed is increased by reducing the amount of drag on the rear wing and while a Formula 1 car achieves this with a moveable flap on the rear wing, on the McLaren P1™, DRS reduces the angle of the rear wing to zero.
The DRS function is operated by a button on the steering wheel and takes approximately half a second to flatten the angle of the rear wing. With DRS enabled, the level of drag is reduced by 23 per cent. The system immediately deactivates when the button is released, or if the driver touches the brake pedal or a steering input is detected.
The McLaren P1™ uses an innovative hydro-pneumatic proactive suspension, called RaceActive Chassis Control (RCC), that gives a wide range of adjustment through variable ride height and spring rates and adaptive roll control and damping. This system means the McLaren P1™ is extremely versatile and can be perfectly tuned for use on either road or track. At its lowest track setting of just 1,174mm, the car can corner at 2g – astonishing for a road car on road-legal tyres.
Suspension – Reactive Chassis Control (RCC)
The suspension system of the McLaren P1™ is incredibly sophisticated for a road car. The hydro-pneumatic RaceActive Chassis Control (RCC) system decouples roll and heave stiffness and can also vary ride height, giving major advantages in ride, handling and grip. The RCC system can be changed by the driver to suit personal preferences and handling and comfort can both be optimised without the usual dynamic trade-offs.
All four wheels are independently controlled and each has its own actuators with pistons for two different circuits, one for roll and one for heave. The damping is adaptive, controlling suspension movement proactively, always ensuring an excellent balance of ride comfort, grip and handling.
The RCC system includes lightweight carbon fibre accumulators, filled with nitrogen, to provide heave stiffness. Roll stiffness comes from two further accumulators, which small springs on each corner maintain the static height of the car. The suspension system is self-levelling, which in normal mode will compensate for passengers and fuel to a tolerance of 4mm.
By using RCC, the McLaren P1™ does away with the need to have anti-roll bars, which are heavy and can compromise ride quality. The RCC system makes them redundant, as it allows the car to maintain precise roll control under heavy cornering while decoupling the suspension in a straight line for excellent wheel articulation and compliance. When the car transitions into Race mode, not only does the ride height change but the suspension stiffness and damping increases significantly to achieve race car-like body control. These changes do not come at the expense of remarkable compliance and driver comfort; the McLaren P1™ delivers a supple ride at low speeds and racing car sharpness at high speed or on the circuit. In full Race mode, the McLaren P1™ has almost no roll – just like a Formula 1 car.
Another Formula 1 technological development that features on the McLaren P1™ is Brake Steer. Used successfully by McLaren on the 1997 MP4-12 before it was banned in Formula 1 for offering a clear performance advantage, the system aids cornering by bringing the vehicle’s nose tighter into the apex. It uses the same hardware as the Electronic Stability Control (ESC) system, requiring no additional components and therefore adding no weight. By applying braking forces to the inside rear wheel when the car is entering a corner too quickly, Brake Steer allows later braking into corners and earlier power delivery on exit.
Vehicle modes – Normal/Sport/Track/Race
The McLaren P1™ has four suspension settings – Normal, Sport, Track and Race modes. The first three settings are selected via a rotary switch; Race mode is selected via a button on the fascia.
The first three modes (Normal, Sport and Track) adjust roll control system pressure, adaptive damping and ESC settings. The active aero wing and flap positions are also changed, while ride height and heave stiffness remain the same in each of the modes. Each setting respectively ensures ideal vehicle behaviour for comfortable cruising, dynamic road driving or track activity.
The Race button makes it easy to quickly change the road-going McLaren P1™ into a fully-focussed track car. When the Race mode is selected, roll stiffness, ESC, damping and the active aerodynamics are all adjusted, as is heave stiffness and ride height. Roll stiffness changes by a factor of 3.5 between Normal and Race modes, while heave and pitch stiffness increases by a factor of 1.4. The car set-up in turn changes to optimise downforce and deliver ultimate track performance, lowering by 50mm, with the rear wing extending by 300mm. The transition into Race mode takes approximately 40 seconds.
The McLaren P1™ is very fast and capable as a road car. But in Race mode, it produces the same downforce as a Le Mans GT3 racing car from the same era.
“It’s a tall order to change the aerodynamics and dynamics of a car, to make the suspension stiffer and to get closer to the road, all at the touch of a button – but that’s exactly what we have done. You don’t need a team of mechanics and a truck with different springs and dampers and wings in order to fully enjoy the McLaren P1™ on the track. A stiff, stable platform is essential when the car is in Race mode. You can’t have body roll or grounding, not when the downforce loads are that big. You can’t change the geometry of that space underneath the car, otherwise you shift the aero balance with serious effects at very high speed. You have to have extremely stiff springing and damping to cope.’”
Dan Parry-Williams, Design Engineering Director, McLaren Automotive
Owing to the incredible performance of the McLaren P1™, tailor-made wheels were designed and developed. The forged wheels – 19-inch front and 20-inch rear – are made from a high-strength aluminium alloy, previously been used for military applications.
A single 10-spoke wheel design is available, in a silver or stealth finish. The elegant design provides the most efficient weight/strength ratio; as with other areas of the McLaren P1™, optimising weight was a major focus and the 19x9J front wheels weigh just 7.94kg each, while the rear 20x11.5J rims are 9.72kg.
Tyres developed with Pirelli
The tyres fitted to the McLaren P1™ are specially developed P Zero™ CORSA tyres, which were developed with Pirelli, McLaren’s technology partner and sole tyre supplier. Pirelli was involved throughout the entire McLaren P1™ development programme and the tyre testing phase was integrated as a key performance component. The end result is a tyre that is finely tuned specifically to the performance and handling characteristics of the McLaren P1™.
In order to develop tyres that complement the McLaren P1™’s characteristics, Pirelli called upon experience gained in Formula 1 and its other motorsport activities, making use of computer simulations that replicated all usage conditions and stresses to which the tyres are subjected.
The construction of the tyres is much closer to a racing tyre than a conventional road car tyre, the specially formulated rubber having a much stiffer construction both vertically and laterally than normal high-speed sports car tyres. This is necessary to cope with the high loading resulting from the downforce in Race mode.
Pirelli’s engineers developed an innovative tyre solution capable of guaranteeing maximum stability and handling. The asymmetric design allows the tyre to remain sufficiently rigid when subjected to different weight transfers and ensures superior contact with the ground, even under cornering and braking. Despite this rigid compound, the tyre and suspension system were developed together to ensure that ride quality is not compromised in non-Race modes.
The tyre belt, bead and sidewall construction are all bespoke to suit the unique requirements of the McLaren P1™. Different structures were designed and developed for the front and rear tyres, each ensuring that torque is cleanly transmitted and traction is optimised. In order to withstand high lateral forces of up to 2g through corners, the bead design on the rear tyres is also asymmetric.
The work carried out on the structures required the use of innovative compounds utilising cutting-edge polymers, to improve stability and resistance to stress. Through the use of these compounds, the tyres reach optimum operating temperature even more quickly, guaranteeing high grip levels and underlining the tyre’s rapid reaction to direction changes.
The tread pattern is a development of the Pirelli CORSA design, enhanced to give the intersection of the inner sidewall and the tread a specific aerodynamic profile, to boost the aero performance of the tyre. The tyre sizes for the McLaren P1™ are 245/35ZR19 front and 315/30ZR20 rear.
Brake system by Akebono
The McLaren P1™ is designed to offer the braking performance and capability of a GT3 or Le Mans sports racing car. Developed specially by McLaren’s Formula 1 partner Akebono, the braking system features a ceramic carbon disc of a type never previously used on a road car, but which has undergone some of the most demanding and extreme testing. Prior to being used in Formula 1 and for the McLaren P1™, the material was used on the Ariane space rocket programme for its heat-resistant qualities. Stronger than conventional carbon ceramic, it dissipates heat more effectively and can absorb significantly more energy through the contact patch between the disc and the pad.
The carbon ceramic discs are infused with a surface layer rich in silicon-carbide – one of the hardest substances known to man. This specially developed highly durable ceramic layer coats the friction surfaces which not only gives superior stopping capabilities but also an attractive mirrored finish.
Akebono applied Formula 1 technology and expertise throughout, focusing on each aspect of the brake system including materials, structure and surface processing, to ensure optimal performance in every area. This produced a highly reliable and efficient brake system that boasts significantly reduced weight, exceptional cooling capability and the ability to withstand high temperatures and maintain rigidity.
The brakes typically run cooler than conventional carbon ceramic but in extreme conditions – such as high-speed track work – they are able to run at very high temperatures without the degradation that would be experienced by the conventional discs. As a result of the discs being able to operate at higher temperatures, they can be smaller and lighter than would otherwise be required; the McLaren P1™ brake discs are 390mm at the front and 380mm at the rear.
The bespoke brake pads are produced in conjunction with Akebono and mounted in Akebono aluminium monoblock opposed callipers (six-piston at the front and four–piston at the rear) that use Formula 1 technologies to deliver light weight and minimise drag.
The braking system has been fully tailor-made to meet the exacting requirements set out by the McLaren P1™, both in terms of performance and weight. Performance of the system is similar to a Le Mans racer – meaning the McLaren P1™ will stop at close to 2g – while offering a weight saving of more than 4kg.
“Many ‘supersports’ cars can suffer during braking on really fast circuits, such as Le Mans, Silverstone or Monza, because they just don’t have enough downforce. The McLaren P1™ has superb stopping power because of a braking system which works in conjunction with the downforce being produced.”
Chris Goodwin, Chief Test Driver, McLaren Automotive
Stopping from 100km/h (62mph) takes just 30.2m (99ft), in 2.9 seconds. From 200km/h (124 mph) the McLaren P1™ comes to standstill in 116m (380ft) in 4.5 seconds, and from 300km/h (186mph) the fierce deceleration brings the car to a complete stop in 246m (806ft) and 6.2 seconds.
To extract the best from the aerodynamic body shape and groundbreaking technologies beneath the carbon fibre exterior of the McLaren P1™, the driver must feel comfortable and at ease. For this reason, the car’s cabin design is clear from clutter and distraction and fully focused on the driver.
The interior offers a cocooning, efficiently packaged, comfortable cabin. Light weight – as with the rest of the car – is a priority, yet the McLaren P1™ retains luxury features such as full climate control, satellite navigation and a bespoke sound system developed with Meridian.
The McLaren P1™ comes comprehensively equipped as standard with an array of colour and trim alternatives as well as visible carbon fibre in the cabin. The options list is limited to fitted luggage and any bespoke content that a customer might wish to add through McLaren Special Operations.
The McLaren P1™ is in left-hand drive form only.
Carbon fibre used extensively
Carbon fibre is used for the dashboard, floor, headlining, doors, rockers and a single piece is shaped for the central control unit to further optimise weight. It is the lightest possible material, while offering the strength desirable for safety and structural integrity.
The attention to detail within the interior of the McLaren P1™ is such that to further reduce weight, the top layer of resin is removed. This saves 1.5kg and also leaves the carbon with a non-lacquered look also that reduces interior reflections.
The amount of trim covering within the cabin is minimised, leaving as many parts as exposed as possible. There is no interior sound deadening in order to optimise weight-saving even further. Carpet is offered as an option, but even then only fitted with a special lightweight backing.
The racing bucket seats are encased in ultra-thin carbon fibre shells and mounted on lightweight brackets and runners, and have an overall weight of just 10.5kg each. The seat backs are set to 28 degrees from the vertical, and there is manual fore/aft adjustment. The decision was taken to not offer separate adjustment to the seat backs or electric adjusters to the base, as these would have added further weight.
The heights of the seats are custom-set to suit driver and passenger and adjusted in a workshop. The seat back can be set to 32 degrees for racing to give more headroom for a helmeted driver. Fixings for a six-point race harnesses are in place, in addition to the standard inertia reel seat belts.
Good visibility a priority
McLaren prioritises packaging – a key to efficient design – and good visibility, which is essential for a first-class driving experience. The interior of the McLaren P1™ feels like the cockpit of a fighter jet, complete with glass canopy overhead. With a windscreen deeper than it is wide, visibility is optimised. The front wheels sit directly below the highest point on the front wings, enabling the driver to position the car precisely.
The ‘shrink wrapped’ design theme extends to the cabin. There is no unnecessary padding or trim. Switchgear is kept to a minimum – for example the ergonomically designed steering wheel features only DRS and IPAS buttons.
To create the smallest frontal area possible and also help airflow to the large rear wing around the teardrop-shaped canopy, the glasshouse of the McLaren P1™ is deliberately narrow. The driver and passenger sit 16mm inwards in comparison to the McLaren 12C, both angled 1 degree away from the centre line. The fact that the weight of the driver and passenger are nearer the centre line of the car reduces the polar moment of inertia, enabling easier changes of direction and greater agility.
The steering wheel diameter is as technically precise as a McLaren racing driver’s wheel. During development of the McLaren P1™, the hand grips of past McLaren world champions were modelled on a CAD system and scanned to produce an exact replica. DRS and IPAS buttons are mounted on the wheel (as in a Formula 1 car) and the steering wheel rim is finished in Alcantara® with carbon fibre inserts. Leather is also available.
An electric hydraulic powered steering system is used. The electro-hydraulic pump is also used to provide the transition between road and Race modes.
In front of the driver are three digital instrument screens: a 6.8-inch central screen and two 3.0-inch outer screens. Built using TFT (thin film transistor) displays, these provide all information about the car. There are four different displays on the main screen in front of the driver, depending on the driving mode. In electric, or E-mode, the amount of power being used and level of charge remaining are highlighted, as well as the speed being displayed digitally. In Normal, Sport and Track modes, the tachometer and speed are given greatest prominence. In Race mode, there is a more race-focused display, including larger tachometer and powertrain temperature. The IPAS and DRS functions are also more prominent.
When the mode is changed to or from Race mode, the screen switches to a transition page that shows a graphic of the vehicle lowering/raising, the rear wing extending/retracting and the transmission, engine and tyres highlighted as the systems are checked. These are illuminated green if functioning correctly, or red should a fault be detected.
The McLaren P1™ is a two-seat car that is extremely efficiently packaged. The front storage compartment is part of the front single-piece clamshell carbon moulding and can house 120 litres of luggage – easily enough for two helmet bags. Further storage can be found behind the front seats in the form of two luggage nets. There are stowage pockets on the front of the seats and three cup holders – two behind the centre console and one in the centre console.
Production of the McLaren P1™ was limited to 375 examples, all of which were hand-built at the McLaren Production Centre (MPC) facility in Woking, Surrey, UK.
The MPC is adjacent to the McLaren Technology Centre, where the car was conceived (and where McLaren’s Formula 1 team is based). The manufacturing facility was opened in November 2011 by UK Prime Minister David Cameron and the then McLaren Group Chairman, Ron Dennis.
The production process
Each McLaren P1™ was custom-built by a carefully selected team of 82 technicians in a four-stage assembly process. From start to finish, the build of each car took 17 days of skilled work and production continued until December 2015.
Stage 1 – structural assembly
The bespoke manufacturing process commenced with the preparation of the MonoCage chassis, the advanced carbon fibre structure at the core of the McLaren P1™.
Stage 2 - painting
The McLaren P1™ features seven lightweight panels: front and rear clamshells, bonnet, doors and front and rear bumpers. The complete set of body panels was painted together to ensure a perfect colour match. This process took three days, including surface preparation of the carbon fibre to ensure flawless paintwork on every single car.
Due to the extended painting processes involved and to minimise disruption to the production of other models, each McLaren P1™ was prepared and hand-painted in a dedicated paintshop in the McLaren Technology Centre adjoining the MPC, while the chassis structure was being prepared.
Stage 3 – trim assembly
The fully prepared carbon fibre MonoCage chassis and hand-painted carbon fibre body panels came together on a dedicated production line within the MPC. A ten-stage process saw the sub-assembly of battery, front sub-frame, doors, rear clamshells and bumpers fitted as the vehicle moved along the line. Two McLaren technicians worked on each of the production stages for the McLaren P1™, each step taking a full working day to complete.
Stage 4 – final assembly
As each car reached the end of the McLaren P1™ production line, it was subjected to the same rigorous testing regime and sophisticated quality control procedures as all McLaren cars, to ensure it met the required quality and performance levels.
This phase of production took a total of seven days to complete and included a full day of ‘shakedown’ at a proving ground. Testing every element of the car’s performance, McLaren test drivers and technicians ran through every different setting and mode of the McLaren P1™ to examine and verify performance ahead of delivery to the customer.
Each example of the McLaren P1™ was then put through the ‘Monsoon Test’, in which 16,000 litres of de-ionised recycled water are released onto a car to ensure all seals are correctly finished. A complete underbody check and diagnostics review was then carried out, before final dispatch audit confirmation.