► McLaren’s 675LT loses its lid
► 666bhp, 0-124mph in 8.1sec
► 500 to be made, all sold out
A neat little case study in supply and demand, the 675LT Spider. McLaren didn’t originally plan to make an open-air version of 2015’s remarkable 675LT Coupe (or, at least, it says it didn’t.)
But sheer volume of interest from customers who missed out on the Coupe’s 500-off production run led McLaren to reconsider, and its engineers to work on transplanting the 650S Spider’s folding roof mechanism.
Two and a half weeks after the 675LT Spider was announced and immediately its entire production run (again, 500 cars) was sold out, despite a £285k asking price. Luckily there’s just enough time for us to go for a drive first, to see what all the fuss is about.
Remind me, what’s this ‘LT’ label about?
It stands for ‘Longtail’, a reference to the final, extravagantly tail-feathered evolution of the F1 GTR Le Mans racer, and it’s the name McLaren now attaches to the most hardcore versions of its road models. Think of it as McLaren’s equivalent of SV, RS or R.
So, in this instance, the 675LT is a harder, leaner, thoroughly upgraded evolution of the McLaren 650S – exactly how thoroughly we’ll come to in a moment. The 675LT is also the first to wear the label, but won’t be the last.
Mind you, LT isn’t a name to be taken too literally. The 675LT doesn’t actually have a particularly long tail, although the rear spoiler is 50% larger than that of the 650S – and big enough to trigger a total eclipse of the rear view mirror when it tilts forward to become an airbrake during heavy braking.
What makes the McLaren 675LT Spider more special than an ‘ordinary’ 650S Spider?
An awful lot. The 675LT Spider is exactly as described; a convertible version of the 675LT Coupe, and technically identical to the LT Coupe apart from that powered folding hardtop in place of the fixed roof.
Consequently it features the same long, long list of upgrades when compared to the original 650S donor car. For starters, it’s been through a weight-saving programme even McLaren’s own personnel describe as ‘obsessive.’ The 675LT Spider weighs a scarcely credible 100kg less than a 650S Spider, at 1270kg dry.
Grams and kilograms have been squeezed from every possible component; throughout the powertrain, from the suspension, from wiring harnesses, from titanium wheel bolts; even the windscreen is a few mil thinner. The air-con system is deleted as standard, but can be optioned back in (we wonder how many of the 500 buyers will leave that box unticked?).
The vast majority of the new bodykit is made from carbonfibre and, as well as looking a whole lot meaner than the 650S, it contributes to a whopping 40% increase in downforce above 155mph. That in turn means the suspension has to endure more load, so it has been stiffened by an enormous 63% at the rear and 27% at the front.
All of the wishbones are new, with a slippery sharkfin-like profile, and are now made from steel instead of aluminium – yet they’ve still shed weight in the process; in total the new wishbones and new uprights save 13kg. The rear track is wider (enveloping the repositioned, outward-turned radiators) and the front suspension lower, but the rear unchanged for a lift-banishing raked stance.
McLaren claims 33% of the car’s overall component count is different from the 650S, and much of that newness can be found within the powertrain. Almost half of the 3.8-litre V8 engine’s internals are different, including lighter con-rods and new camshafts, along with lighter charge air coolers, new turbochargers with a higher flow rate, electronically operated dump valves and a faster fuelling system. Apart from shedding weight, many of the engine’s ancillaries have conversely been beefed up to withstand being sped up and slowed down more violently.
Oh, and let’s not forget a brand-new titanium exhaust system. The net result is that power has jumped from 641bhp to a beastly 666bhp, and peak torque from 500lb ft to 516lb ft – but it’s how that extra go is delivered that’s the real story.
Spare me the engineering lecture. How much faster has all that tinkering made this car?
Fast enough to smash 0-62mph in 2.9sec and hit 203mph flat-out (2mph less than the Coupe. Oh well). But the really head-scrambling stat is 0-124mph in 8.1sec.
We can thank the 524bhp power-to-weight ratio for that, as well as the motorsport-developed ignition cut system for brutally rapid gear changes. Ordinarily the gearbox software cuts the fuel to the cylinders on upshifts rather than the spark; the LT’s system can do the opposite which is stated to permit faster changes.
McLaren says it actually deliberately sacrificed some low-end torque for a more dramatic-feeling torque curve in the mid-range during sustained acceleration through the gears. A sub-3sec 0-62mph time doesn’t seem too terrible a sacrifice…
Okay. So how does it feel to drive compared with a 650S?
More special, more engaging, and quite a lot faster. Swing the door upwards and you’ll freefall into the most perfect of driving positions. The LT’s one-piece bucket seats (total weight saving: 15kg) mean you sit a little lower than the 650S’s powered comfy chairs, with fantastic forward visibility through the globular screen. During our test its single wiper blade was working overtime to clear heavy rain – thank goodness we were on the standard Pirelli P Zeroes rather than the optional tread-shy Trofeo Rs for our Scottish Highlands-based test.
On the move you notice the steering first; the LT’s new, faster steering rack (quicker even than that fitted to the McLaren P1) is not only laser-accurate, but brimming with feel too. Then you’ll notice the road noise. With much of the sound deadening binned to meet that 100kg weight loss target, NVH is not one of this car’s strengths. The ‘N’ bit, at any rate.
Ride quality, however, is. Despite being stiffened by such an extreme degree (60% at the rear, remember!) the McLaren’s computer-controlled hydraulic suspension still absorbs bumps surprisingly sweetly. It’s firm, yes, but not much more so than the average hot hatch – and with infinitely better body control.
Despite the LT’s ultra-focused ethos, it’s still very much a road car, not a stripped-out special that only makes sense on a race track. Twist the stereo’s volume control past the road noise and it’s as usable as supercars come.
And does it feel fast?
Oh good gosh, yes. About 20% throttle is enough to decimate more or less anything else in the road. With the gearbox in ‘ignition cut’ mode upshifts are whip-crack fast, and make a similar sound effect, with unburnt fuel firing a musket-like bang on almost every upshift.
That titanium exhaust system sounds more nuanced, less industrial than the regular 650S, too. There’s still a slight, unavoidable woolly edge to the twin-turbocharged V8’s throttle response – you can’t help but wonder what the McLaren would feel like with a less powerful but more responsive naturally aspirated engine. Still, the LT’s monstrous mid-range pace is a pretty special experience.
What’s the roof like?
Exactly the same as the one on our long-term 650S Spider: three pieces, capable of folding themselves away while the car’s travelling at up to 25mph. Roof up, it’s still possible to independently drop the rear glass – all the better to hear the twin-turbo V8’s fireworks.
Roof aside, any other differences between the LT Coupe and Spider?
Those fussy 20-spoke wheels, available in two finishes. Reportedly the engineers groaned when the design team said they wanted to do a wheel with so many spokes, but the end result is actually very strong and very light – and not all that much heavier than the LT Coupe’s 10-spoke design, which were the lightest road car wheel McLaren had made to date.
The idea of an extreme, driver-focused supercar with a folding roof seems counter-intuitive. But the de-roofing actually adds an extra dimension to the 675LT, allowing the driver to experience its thrills even more viscerally in the open air, while barely affecting the car’s tub-bound rigidity.
Let’s hope the lucky 500 LT Spider owners don’t lock their cars away in bubblewrap as an appreciating asset but actually drive them. They’ll be missing out if they don’t.
Read CAR's long-term McLaren 650S Spider test diary here
Read Chris Chilton’s review of the McLaren 675LT Coupe