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McLaren has revealed new details of its Senna hypercar, dubbed the ultimate road-legal track car. Autoweek attended the technical deep dive at McLaren’s new carbon-fiber production facility in Sheffield, England, which opens in 2019. We interviewed key personnel, pored over the $958,966 Ultimate Series model and eyeballed Ayrton Senna’s McLaren MP4 Formula 1 race car.

Only one crucial component was missing: arguably the ultimate road-legal track driver, Chris Goodwin. Former McLaren veteran Goodwin now works for Aston Martin, which is set to launch its own mid-engine super- and hypercars. Aston insiders insist Goodwin wasn’t poached but was approached after he quit McLaren.

Anyway, no matter who’s driving, the Senna should be sensationally quick in a straight line. The claimed acceleration figures are 2.7 seconds to 60 mph, 6.8 seconds to 124 mph, with a 9.9-second demolition of the quarter-mile and 211 mph top end.

That’s partly because the 4.0-liter twin-turbo V8 first seen in the 720S Super Series model is boosted to 789 hp and 590 lb-ft (up from the 720S’s 710 hp/568 lb-ft — though most are said to make much more), and gets lighter cams and pistons, an ECU tweak, plus the benefit of a roof snorkel and new inconel and titanium exhaust.

But it’s also partly because the center lock wheels run sticky Pirelli P Zero Trofeo R tires, measuring 245/35 ZR19 at the front, 315/30 ZR20 rear.

McLaren Special Operations creates the beastly MSO X 570S

The making of a lightweight

Dumping weight wherever possible sure doesn’t hurt, either – and ultimate purity means there’s no heavyweight hybrid this time, as there was on McLaren’s previous Ultimate Series model, the P1. Without fluids, with all lightweight options ticked, the Senna is claimed to weigh 2,641 pounds — the lightest McLaren since the 2,509lb F1 of the 1990s. The power-to-weight ratio is 659 hp per ton.

As ever, a carbon-fiber tub sits at the Senna’s core, but it’s evolved with a new double-walled rear crash structure that removes the need for a roll cage, called MonoCage III. What really makes the difference over the Senna’s siblings is lightweight carbon-fiber bodywork, with panels weighing just 132 pounds combined.

Some panels were laid out for us to inspect, and they certainly felt as light as the stats suggest. The front fender weighs just 1.5 pounds, compared with 4.8 pounds for the 720S. The door, with its complex molded-in aero features, comes in at 21.8 pounds, less than half a 720S. Even the seats weigh just 7.4 pounds.

McLaren Senna rear view wing and diffuser

That massive rear wing is said to generate 1,102 pounds of downforce — and it weighs just 11 pounds.

All about aero

The Senna makes a claimed 1,764 pounds of downforce at 155 mph, 40 percent more than the P1. The huge active rear wing has 25 degrees of movement (and weighs just 11 pounds) yet is said to generate 1,102 pounds of downforce alone. It’s more effective than the 650S GT3 race car rear wing that was used on early test mules.

To balance it, McLaren has a front splitter some 5.9 inches longer than the P1’s, with active aero blades hidden in ducts close to the headlights that adjust in harmony with the rear wing’s movements. Instead of low-temperature radiators pushed out to the Senna’s far front corners, they’re housed inboard — it’s why there’s no frunk, just vents big enough to hold a rucksack, though that’s a bad idea.

Air management has been harnessed wherever possible — the small side windows only move at the bottom, allowing the top of the glass to be flush and therefore more aerodynamic. The huge side intakes allow smaller, lighter radiators; the flat underbody culminates in an upswept double-diffuser made from one piece of carbon.

Compared with the P1, lateral grip increases by a claimed 30 percent. That’s down to those tires, but also Race Active Chassis Control II, a development of the hydraulically interlinked double-wishbone suspension seen on 720S and P1.

Just like the P1, the Senna lowers when you select Race mode — the front by 1.2 inches, the rear by 0.9 inch, the slight rake enhancing aero too.

McLaren Senna interior

Inside the Senna.

Braking is taken care of by carbon-ceramic brakes measuring 390 mm all around, with six-piston monobloc calipers that require the entire caliper to be removed to change pads but promise excellent pedal feel. Dubbed CCM-R, McLaren claims the brakes are 60 percent stronger and four times faster to dissipate heat than regular carbon-ceramics, and they take just 100 meters to stop the Senna from 124 mph.

McLaren refers to the Senna’s design as “brutal,” and it’s certainly challenging to behold – the front overhang is enormous, the side intakes overblown, the rear wing cartoonishly out of proportion. There were some sniggers when McLaren said all 500 units sold out before customers even saw the car, but a spokesman quickly added that none canceled following the reveal. Around a third of those cars are heading our way.

But perhaps ugly, if that is how you choose to see this machine, doesn’t matter so much if the Senna really is the ultimate road-legal track car. We’ll find out if it is — and if Goodwin’s exit has made a difference — when we drive it at Estoril, scene of Senna’s first Formula 1 victory in 1985, this June.

By Ben Barry