How do you turn the wick up on the McLaren's insanely focused Senna road car? Make a track-only version, obviously. That's exactly what engineers will start doing this month as testing for the 75 Senna GTRs begins on circuit, with deliveries set to commence in September 2019. As previewed by a concept model shown at the Geneva motor show in March, the GTR will build on the extreme base of the road car with a racing car-esque transformation, including mental aerodynamics, even less weight and extra power. It's a recipe to make a millionaire wannabe-racer weak at the knees.
We now know that the finished GTR will produce 825hp and 590lb ft of torque from a further developed version of McLaren's turbocharged 4.0-litre V8 engine, meaning it has 25hp more than the road going Senna. That boost will come alongside hefty weight saving measures, enabled by the binning of non-essential parts such as airbags, infotainment and other hefty cabin materials. The only mod con to remain will be air conditioning, because nobody wants to feel clammy at 200mph.
McLaren is yet to confirm the exact amount of weight saved by the Senna's diet, but if we assume about 100kg is removed from the 1,309kg road car (and that could be a conservative estimate given that the P1 GTR lost 150kg in its transformation), that would give the GTR 682hp per tonne. This would be a 71hp/tonne improvement, enough to make a very noticeable difference to progress in a straight line.
Yet it's likely that the improvement to progress around corners will be even more significant, as McLaren says the GTR, free from the burden of any road or motorsport regulations, will be capable of generating substantially more lateral grip. This will come thanks to the aerodynamic and chassis changes made to the track car, which centre around its steroidal bodykit and widened track, as well as a set of sticky slick tyres and GT3-derived dampers and anti-roll bars.
McLaren's Geneva concept showed us how far Woking aerodynamicists want to go with the GTR's formula, as it sported an enormous, blade-like front splitter and a vast rear diffuser so large it could double up as the family dinner table. Assuming they're all retained, these new features will work with the car's existing active armoury of wings, channels and ducts, which will combine to help the GTR generate up to 1,000kg of downforce. That's 200kg more than the road car, for those wondering.
The missing piece in the GTR puzzle is found in braking power, which, of course, will also be improved. Some improvement will come naturally thanks to the GTR's reduction in weight and increased downforce, but also via the use of race-derived brake hardware and an accompanying reduction in pitch movement with those GT3 chassis components. McLaren says to expect an eyeball-popping 20 per cent improvement over the road car here, so the Senna should pull up to 3G with the left pedal fully depressed.
Such a transformation was always going to bring a hefty increase over the standard Senna and its £750,000 price. If you've bagged a GTR build slot and you're in Britain paying Her Majesty's taxes, you'll already have readied £1.32 million. If you haven't secured one, you're sadly too late because all 75 examples of the GTR are spoken for - and have been since the Geneva show.