McLaren reveals wild track-bred 600LT

McLaren has unveiled a faster, lighter and more powerful Longtail version of the 570S that's claimed to be quicker than the car-maker's previous 675LT around a race circuit.

Called the 600LT, the hard-core supercar has been created to rival cars like the Ferrari 488 Pista and the Porsche 911 GT3 RS.

Packing the same twin-turbo 3.8-litre V8 as the regular 570S, the 600LT takes its name from the 600hp (440kW) that's produced by McLaren's uprated engine.

Engineers say the newer 4.0-litre V8 twin-turbo from the 720S was considered but ruled out due to issues with packaging its airbox -- that, and fears the baby supercar could overshadow its bigger brother for showroom appeal.

McLaren hasn't yet released performance figures for the 600LT, but thanks to the blown bent-eight managing to churn out 620Nm of torque and a weight-saving of around 100kg, expect a 0-100km/h time of less than three seconds and a top speed in excess of 330km/h.

Sticking with tradition, the 'Longtail' does indeed sport a rear-end that is some 47mm longer, while up front the splitter is 27mm longer.

The extended bodywork is just a hint at some substantial changes over the 570S, with McLaren claiming that 23 per cent of the 600LT is all-new.

Following extensive wind tunnel testing, the smallest Longtail's boats a lengthened body and an enormous rear diffuser made possible by repositioning the exhaust and give the 600LT a pair of top pipes.

The result is the 600LT generates 100kg downforce at 250km/h, distributing 40kg over the nose and the rest over the rear of the body.

Those top-exit exhausts are quite the show-piece. Lifting the idea from the Ultimate Series P1 hypercar, engineers claim they shave a substantial 12.6kg off the kerb weight while reducing back-pressure to produce more power.

Look closely and you might notice a rear spoiler with a nifty ceramic-coated centre. Without it, the fire-spitting antics of the new pipes would melt or, worse, torch the wing.

Weight reduction dominated the development of the 600LT. Originally, a target of 100kg was set and then immediately ruled out as impossible by bean counters due to cost.

Engineers reluctantly lowered their ambitions and settled on 90kg, which McLaren says is the amount of mass reduction the average driver can 'feel' behind the wheel on a sub-1400kg car.

But, secretly, the original target remained in place. And to achieve its aim, it's an understatement to say McLaren went to extreme lengths to shed weight.

Peer into the cabin and you might notice the very same ultra-lightweight bucket seats lifted from the Senna hypercar. This alone carves 21kg off the kerb weight.

Then there's the option to delete the air-conditioning (-12.6kg), opt for a carbon-fibre roof (-3.6kg), or plump for some cool MSO carbon front fenders.

The attention to detail is stunning. The electrical harness is trimmed back to save 3.3kg, while lighter suspension components bring a hefty 10.2kg loss. Carpets? Forget about them, and same goes for the glovebox and front axle lift system (-10kg).

In total, the stripped-out 600LT tips the scales at just 1247kg (dry) -- 33kg lighter than the 488 Pista.

However, controversially, one engineer we spoke to told us that its Italian competitor is nowhere near its claimed weight, joking that Ferrari's scales were "beyond broken".

Even the door pockets are replaced by nets to save mass.

Capitalising on its lower weight and higher power, McLaren gave the 600LT a thorough retune of the already accomplished chassis, lowering the suspension (-8mm) and widening the track to focus on increasing grip and raising corner speeds.

Tyre-partner Pirelli also lent a hand developing a bespoke version of its P Zero tyre. The result is a car that is "quite a margin" faster than the 675LT on most circuits you care to name.

Reigning in all that power is a braking system developed on the 720S.

As well as making it faster, McLaren claims it has improved feel and feedback provided by the 600LT's steering which, incidentally, has been quickened for the junior Longtail.

Other changes include doubling the stiffness of the engine mounts, which is claimed to enhance the connection between man and machine.

Then there's the exhaust that is far more audible in the cabin, in part thanks to thinner glass.

Perversely, McLaren claims that, on track, the top pipes are actually quieter than conventional rear-exit exhausts as there's no road to amplify the sound.

A quick demo reveals a savage, hard-edge bark in keeping with the aggressive look of the 600LT.

When deliveries begin in October 2018, the 600LT will cost around 25 per cent more than a 570S.

That would see the hard-core McLaren priced around the $470,000 in Australia – around $53,000 more than a Porsche 911 GT3 RS.

Justifying the premium, McLaren will limit the number of 600LTs produced, although production numbers will be far greater than those of the 500 675 LT Coupe and 500 675LT Spider.

Speaking of which, a 600LT Spider has already been confirmed and is set to join the range some time in 2019.