McLaren has officially pulled the wraps from the 675LT (Longtail), the latest addition to its Super Series range. The new car is more track-focused than its stablemate the 650S and according to global marketing director, Jamie Corstophine, is something customers have asked for, rather than a point-scoring exercise in bettering competitors’ performance figures. The new car goes on sale in July at a price of £259,500 and will be limited to 500 units. The 675LT is 100kg lighter and at 666bhp, 25bhp more powerful than the 650S, and that much was revealed before the show. However, further details revealed by McLaren suggest technical changes should add up to an enhanced driving experience that goes beyond mere brute power.
First, there’s the weight: 100kg is a lot. It’s the equivalent of an average male person plus an airline baggage allowance. “The reduction in mass makes the biggest difference to the way the car feels,” says Mark Vinnels, McLaren’s programme development chief. Weight has been paired from “wherever we could find it” he adds, including from suspension components, the wheels, which are the lightest ever fitted to a McLaren production car, body panels and the carbonfibre wing that not only contributes to the 675LT’s 40% higher downforce but is lighter than the one fitted to the 650S. The exhaust is made from super-lightweight Titanium and crosses over to allow an optimum, longer length to be packaged inside the car. The net result is a supercar that’s even more connected to the driver than the 650S, if that’s possible, and nimble, too. “Put a bit of lock on, with the ESP off, and the car will pirouette around the nose badge in perfect doughnuts,” enthuses Vinnels.
Chris Goodwin, the development driver, explains how his team worked hard to exploit those characteristics with fine tuning of the suspension geometry and to connect the driver with them. Goodwin subscribes to the traditional philosophy that to get the best from a car, the driver should feel part of it. A snug-fitting seat and good pedal feel are essential to create that sensation of being wedded to the car “but they’re not everything,” he says. “When I drive it has to be intuitive. When I brake I want to extend my foot no farther than where I think the braking effort should start and when I steer, I want the car to follow my eyeline without consciously thinking about how much I’m moving the wheel.”
Goodwin and his team spend many hours tuning what he calls “the relationship between the tyre and the road surface.” He talks about “‘feeling the grip’”; sensing the tyre bite into the road surface as the steering wheel is moved. However, that elusive optimum feel can be lost in an instant by making a bad choice. “It’s easy to screw up the geometry, for example, by dialling-in too much steering caster to try to increase feel.” Do that and it’s possible to overwhelm that subtle relationship between the tyre’s contact patch and the road surface, he explains.
One of the more subtle, but possibly most important changes, has been to the transmission. McLaren believes this to be the first production car to feature ‘ignition cut’ on full-throttle up-shifts, rather than the traditional method of cutting the fuelling for a few milliseconds. Do that, explains Vinnels, and the fuel has to be reintroduced to the engine, which takes time. Ignition cutting is typically used in race cars with sequential transmissions to achieve a ‘flat-shift’. It kills torque instantly and when the shift is completed, it reinstates torque just as quickly. The whole process is faster than the blink of an eye and much, much faster than a heartbeat. The McLaren men are understandably enthusiastic about the fun factor this feature delivers. “It’s part of this process of integrating the driver with the car, and it takes driver involvement to another level,” concludes Goodwin.
By Jesse Crosse
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