Active aero is what separates the road-legal P1 from it rivals in Stuttgart and Maranello. Working in conjunction with the rear diffusers and active side flaps on the front wing, in Race Mode the active rear wing develops 600kg of downforce at 161mph. There’s also a Formula-1-apeing drag reduction system that flattens the wing and reduces drag by almost a quarter on the straights.
The GTR, however, has no obligation to behave itself on the road, and so has an enormous fixed rear wing that looks stolen from something competing in the GT3 Championship. It sits 400mm above the vacuum-packed rear bodywork and helps increase downforce to 660kg at 150mph. Propped up by lightweight carbonfibre supports, the wing’s pitch can also be trimmed from 32 degrees to flat by the driver, reducing drag in similar fashion to the road car.
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A garden-spec McLaren P1 is already a very light car, weighing in at 1395kg dry, despite carrying a lithium-ion battery pack and a seven-speed dual-clutch gearbox.
The GTR will mount the scales with even more delicacy, however, and alongside a lightweight exhaust and stripped-out engine componentry, motorsport-spec polycarbonate side windows will be employed and the chemically toughened glass panels in the roof will be sacrificed for carbonfibre pieces. The car’s engine bay cover is also now carbonfibre, while the road car’s 3.2mm-thick lightweight windscreen remains. Even engine ancillaries required for road use but not for the track have been banished.
Overall, McLaren claims that these modifications reduce the P1’s weight by 50kg, which while no mean feat still makes the GTR some 180kg heavier than the Ferrari FXX K.
With a power-to-weight ratio of roughly 750bhp/tonne, performance will be limited only by how much power the P1 GTR can put down on the ground through its 13-inch-wide Pirelli rear slicks.
The road-going P1 has a claimed top speed of 217mph and registers a 0-62mph time of 2.8 seconds. It’s likely that the GTR’s fixed aero will curtail its top speed and a killer sprint time off the mark will depend on whether McLaren has equipped it with a version of the road car’s sophisticated launch control function. McLaren is yet to publish figures.
Nevertheless, once up can running, performance will certainly be explosive. To recant our own hugely experienced road tester David Vivian’s initial experience with the ordinary P1: ‘The shock of the P1’s acceleration has pulled me so far out of my comfort zone I can hardly swallow.’ McLaren’s driver training scheme for GTR owners has a sizeable task on its hands, we imagine…
P1 GTRs will be offered exclusively to P1 owners, so you could say the requisite price is £866,000 in addition to the £1.98million McLaren is asking for the car. Production will start once all 375 examples of the road car have been built.