The 'LT' bit stands for Longtail, named after the three McLaren F1 GTR Longtails that were homologated to keep the F1 competitive in sports car racing in 1997. The F1 Longtail was longer, lighter, faster; so is this car. At £259,500, it’s more expensive, too.
LT is now more about philosophy than length, though, because the 675 is only 3cm longer than a 650, but with its new front splitter, 50 percent larger rear wing and new underbody and side addenda, it makes 40 percent more downforce than the 650. The body changes are all in carbonfibre, which contributes to a weight saving as well as the downforce increase. The 675, at 1320kg (1230kg dry), is 100kg lighter than a car that was not noted for its portliness in the first instance.
Looking for areas from where to trim eight percent of the mass means that even the wiring loom is 3kg lighter, the windscreen glass is 0.5mm thinner and the engine cover is Plexiglass – although its holes, like the vents at the rear and the fact that the radiators have been turned sideways, are about getting heat from the car rather than lightening it.
There are more stats – lots more, like the fact that the conrods are 11 percent lighter and that the engine cuts the ignition on upshifts, so the engine’s speed change rate is 55 percent faster – but what makes the 675 the car it is are the changes McLaren has wrought to the chassis.
The steering rack is faster even than a P1’s, spring rates are 27 percent stiffer at the front and some 60 percent stiffer at the rear, and the front tyre grip has been increased by 6 percent.
All of which is centred around making the 675LT more agile, responsive and rewarding; and more of a car that is prepared to indulge your childish side in a way that, P1 aside, modern McLarens hitherto have not. They’ve had launch control, for example, but not a launch mode which will give you massive, long, smoky burnouts. The 675 has one of these.
It’s a car you wouldn’t always know was wild. McLaren says, yes, inevitably you’ll want to talk competitors to the 675 LT – the Ferrari 458 Speciale is obviously the one that comes to our minds – but, says McLaren, this is a car that has many rivals, not just one, because it’s so broadly capable. And so it proves.
The 650 was always a car with ride quality to spare, and even though it has given up a little of its compliance, still it’s a car that rides with flatness and composure that track special sports cars – or plenty of saloon cars, for that matter – simply could not match. Even though it’s firmer this is still a car in which you could comfortably cross a country on your way to a track day.
And it steers beautifully. The faster rack gives no hint of nervousness but oodles of feel and finesse. That the 3.8-litre flat-plane crank engine makes a more satisfying sound than ever, that the gearshifts are shorter and that the exhaust prone to popping unburnt fuel mean the 675LT is an engaging, rewarding road car.
You still get three modes of damping stiffness and powertrain anger, too, so you can turn up the noise yet leave the suspension relatively supple. On the road, where the traction control is regularly tested and sublimely metered, I recommend you do.
On a circuit, though, it is best if everything is turned to 11, and here’s where you feel the greatest difference between the 650S and 675LT. The basics are still there: it’s still whoppingly fast and the brakes are phenomenal. There’s still a touch of stabilising understeer if you drive smoothly, and there’s still brake-steer and an open rear differential.
But it’s in the details and nuances of the handling balance where the 675 has finally fulfilled the potential of this McLaren model line; where it has finally become a truly adjustable mid-engined car, with a nailed-down front end and a tail that is prepared to move around under acceleration, or that can be provoked on turn-in.
It is quite a bit more mobile, that degree more agile; not just prepared but actually willing to tackle a corner at the attitude you choose, not just at an attitude that’s fast. The 675LT is fast, mind – closer in lap time to a P1 than a 650S around most race circuits.
Don’t want one only because the 675 LT is quick. The difference you’ll note from behind the wheel is not necessarily how much faster you’d be going than in a 650S, but how much more fun you’re having while you’re doing it.
Until now I’ve felt this car – and by which I mean MP4-12C, 12C and 650S – has just needed to loosen its top button, worry less about impressing people and kick back and unwind a little. In the form of the 675 LT it has become precisely that car.