Remarkably, the Senna weighs barely 300 pounds more than McLaren’s first ever road car, the iconic F1. Built in 1992, the F1 was, even then, a back-to-basics car lacking traction control, anti-lock brakes, or power steering in the interests of weight saving. The Senna not only boasts all those features but also meets much tougher crash safety standards, right down to front and side airbags. Here’s how McLaren did it.
The Carbon Fiber
McLaren knows a lot about carbon fiber. It’s been at the core of every car it has built since the MP4/1 grand prix racer—in 1981 it was the world’s first with a carbon fiber chassis. In the Senna, McLaren takes its carbon-fiber fabrication skills to almost F1 levels of lightweighting. The single skin door weighs 21.6 pounds compared with the 41.9-pound door of a 720S. The front fender weighs 1.5 pounds versus a 570’s 4.9-pound fender. Each carbon-fiber seat shell weighs just 7.4 pounds. That massive active rear wing weighs 10.7 pounds but delivers more than 100 times that in downforce on the rear axle at 155 mph. The 6.4-pound carbon-fiber intake plenum is half the weight of the 720S’ cast aluminum item.
The Brakes
Each of the Senna’s race-spec CCM-R carbon ceramic brake rotors takes seven months to make. That’s seven times longer than it takes to make a normal carbon disc, but they have four times the thermal efficiency and are 60 percent stronger, which means they can be smaller in diameter while still delivering superior performance. Smaller means lighter overall, and, importantly, less unsprung mass. Engineers even removed the raised McLaren logo from the brake calipers to save precious ounces of unsprung mass.
The Aero
With massive intake vents ahead of the rear wheels, and a swathe of louvers on their upper surface, the rear fenders have been designed to duct as much air as possible through the high-temperature radiators on either side of the engine. That means instead of needing bigger, heavier radiators to cope with the more powerful engine’s higher thermal loads, the Senna can use the same size radiators as the 720S, mounted low in the chassis to help handling.
The Options
Air conditioning is standard but can be deleted at no cost, saving about 37 pounds. Even though McLaren insiders say the Senna will be loud and raw as well as fast, a $5,680, seven-speaker Bowers and Wilkins audio system is available as an option. It weighs just 16.1 pounds. Also optional is a lightweight paint unique to the Senna. Called Caliber Black, it has been specially formulated to reduce the volume of liquid needed to provide coverage.
The Detail Stuff
The new high-flow fuel pumps are so efficient the Senna only has two of them, one less than needed to fuel the Mclaren P1 engine. The ultra-light iconel and titanium exhaust exits through the top surface at the rear of the car simply because it’s the shortest path from the engine. The half-drop side windows mean they can be powered by smaller, lighter electric motors. The passenger seating position is fixed, eliminating the need for any weighty adjustment mechanism.
Read our McLaren Senna First Look here.
The post McLaren and the Lightness of Being: 5 Cool Facts About the Lightweight Senna appeared first on Motor Trend.
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