Lambo's next big event: LP700-4 Aventador

Geneva International Motor Show

The Murcielago's welded alloy tube-frame chassis was an old-school life-support system for its monstrous, but dated, 6.5-litre V12. For all its brutal charm, much of its technology was rooted in the past. What Lamborghini needed, its president claimed, was a two-generation leap.

And, technically at least, that's what his engineering team have delivered with the Aventador LP700-4. Clad in a typically aggressive bodyshell, it's based around a breakthrough carbon-fibre chassis, clings to the road with pushrod suspension, changes gear through a radical seven-speed gearbox and punches it all forward with a brand-spanking new V12 engine.

With 700 horsepower (522kW) and 690Nm of torque, the new motor is seriously oversquare, 6.5-litres, lighter than the old engine, revs hard to 8250rpm and is strong enough to throw the Aventador to 100km/h in just 2.9 seconds. Top speed, Lamborghini officially claims, is 350km/h, though engineers admit to seeing more than that in testing...

While Lamborghini has released details of the Aventador's driveline before, it has been reserved on the supercar's other details. We can now finally reveal that it combines three different carbon-fibre technologies to make its chassis.

It's perhaps the technical breakthrough with the widest-reaching future, given that Audi is keen to poach some of Lambo's carbon prowess, because it gives the Aventador a passenger cell weighing just 147.5kg, but with a torsional stiffness of 35,000Nm per degree -- more than double the Murcielago's number.

This torsional stiffness, coupled with race-inspired pushrod suspension setup and double, forged aluminum wishbones all round, give the Aventador the handling accuracy it needs to cope with the frightening speeds the engine can produce.

Aluminium subframes are bolted to it at both ends to give Lamborghini somewhere to attach the engine, gearbox and suspension parts. But even then, the body-in-white is only 229.5kg.

Somehow, though, by the time Lamborghini added everything else, the Aventador ended up at 1575kg -- or 10 more than the old Murcielago SV and only 90kg lighter than the Murcielago LP650-4. It's better than being heavier, but it's a far cry from the 200kg weight saving that was being talked about only half a year ago.

While Lamborghini is staying mute on the subject, our information is that it switched to plastic panels (even though they give them a fancier, technical name) for cost reasons, and they are considerably heavier than the Murcielago's carbon ones. Still, with a 47.5:52.5 front-to-rear weight distribution in the LP700-4, an Aventador SV is already an enticing prospect...

Lamborghini has built a new, 5400 square metre carbon production facility at Sant'Agata to build and bring together the three different carbon-fibre production methods that come together on the Aventador -- two of which have never been seen anywhere else before.

The first is RTM Lambo; an RTM (Resin Transfer Moulding) system developed by Lamborghini and the University of Washington, of which most of the tub is made. There are a lot of technical and production benefits to it, including high levels of automation, no hand lamination, no autoclave, lighter, carbon-fibre moulds rather than steel or aluminium ones, a 2.5 bar resin injection pressure (as opposed to the traditional 6) and far lower curing temperatures.

Lambo then uses epoxy foam shapes to build spaces inside the tub which also double as harmonic dampers. Then there's another carbon breakthrough, called Braiding, which weaves carbon strands into tubular shapes ideal for adding strength in the A-pillar and down in the sill. They are also easy to replace in collisions.

Lamborghini also uses the traditional, labour-intensive prepreg system for all the surfaces people see and touch, because it gives a better look and is easier to paint. It combines all three carbon systems and cures them together and still manages production tolerances of just 0.1mm.

Attached to this at both ends are pushrod suspension systems, which remotely relay the wheel forces to spring, and Ohlins damper units mounted directly to the chassis. Up front, this forged aluminum pushrod attaches to a unit directly in front of the windscreen, while the rear units sit almost horizontally and attach just behind the engine.

Lamborghini claims this is a far more accurate way to design suspension architecture and has been derived directly from motor racing: Formula One and Indycars all run either push or pull rod suspensions.

The new suspension layout allows for larger braking units: the Aventador uses massive 400mm x 38mm carbon-ceramic rotors clamped hard by six-piston monobloc calipers at the front. The brake diameter at the rear is still 380mm x 38mm, and uses a smaller four-piston caliper.

There are custom-designed Pirelli PZeros all round, too, with seemingly tiny 255/35 R19s up front (steered by a new electro-mechanical steering system) and monstrous 335/30 R20s at the back.

While the Aventador promises to be a more integrated car than its predecessor -- which was little more than a delivery system for its engine -- the LP700-4 discussions will be centred on its all-new motor.

A clean-sheet engine is a rare thing these days, and it's even more rare when you're talking about 500-800 cars a year.

Yet a clean sheet is exactly what Volkswagen Group boss, Dr Martin Winterkorn, gave Lamborghini's engineers, and they ran with it.

At 6498.5cc, it's roughly the same size as the old Murcielago engine, but that's where the resemblance ends. Its crankshaft is different, its cylinder heads are different, its bore and stroke is different and its bore centres are different. The only thing it retains is a 60-degree vee angle.

There's plenty of power, because that's Lamborghini's way. Four throttle bodies help it to 700 horses at 8250rpm and 690Nm of torque at 5500, yet it's a monstrous big thing and needs a big hole in the engine bay to carry it.

It's an enormously oversquare device (at 95mm x 76.4mm) mainly, as Technical Director Maurizio Reggiani admitted, to reduce piston speeds at its 8250rpm power peak to just 21 metres/second.

Still dry sumped, the engine has a silicon-alloy crankcase with seven bearings and a bedplate with eight integrated scavenge pumps to extract any last drop of unwanted oil.

The crank itself is a far lighter (24.6kg) and stiffer unit, forged and nitride hardened, and spins beneath a pair of 32-valve cylinder heads (21kg each) that contain variable valve timing and lift technology, plus in-cylinder ionization to precisely control each spark and prevent any pre-ignition. Lamborghini insisted on this last piece of technology because, at 11.8:1, its compression ratio is high, enough to warrant more precision in case of poor fuel.

At 235kg, it's 18kg lighter than the old engine, its sump sits 60mm lower in the chassis and it's even got the rear diff housing cast into the back end of the block. That still doesn't mean it's small, though, at 784mm long, 665mm high and 848mm wide, even with the three-to-one exhaust manifolds in place.

If Lamborghini has one issue to spin with the weight of its carbon supercar, there's another with the fuel-delivery system.

It claims a 20 per cent reduction in fuel consumption and emissions (taking it down to, ahem, just 398 grams of CO2/km on the combined cycle), yet all isn't quite what it appears. There's no direct fuel injection, even though the Gallardo uses it, so the Aventador has a multi-point system and the engine contributes only about a quarter of the fuel-economy improvement.

But this engine -- an unforgiving refinement of existing road and race principles -- wasn't developed in isolation. While once Lamborghini's engine development stood alone, it's now part of a powertrain department, so it was developed in concert with the new electronic architecture, the new Haldex IV centre diff, the diffs, the driveshafts and, last but definitely not least, the gearbox.

The old six-speeder was past its time and, in keeping with the "two generations" ethos, Lamborghini and Graziano developed the most radical, audacious gearbox in production today.

The seven-speed unit is called an ISR (Independent Shifting Rods) gearbox, and boasts the fastest gearshift in the production car world today. At 0.05 seconds in its Corsa mode, it can change gear faster than the Ferrari Scuderia or 599 GTO.

It's a two-shaft gearbox (again, designed from a clean sheet of paper) and it's been derived from ideas used in racing gearboxes developed by Australian, Peter Hollinger. It breaks up the traditional gear pairings so that, as one gear is disengaging, the next one can be engaged by a different shifting rod simultaneously.

What's more, an all-new computer system capable of half a billion calculations a second can control the movement of each of the shifting rods independently and minutely, so it can give an ultra-smooth shift when you're cruising and a fast, aggressive shift when you're attacking.

All of its hydraulic lines are cast directly into the alloy casing, so there are no external lines. Even more innovative is that all seven gears (plus reverse) use carbon-fibre synchromesh cones.

The whole unit is 120kg, which is 1kg lighter than the old gearbox, but with an extra gear, and there's far less rotational inertia, too.

"It's a completely new electrical system," Reggiani confirmed. "We don't have one for the engine, one for the box, one for the AWD. There's just one system and it's based on a master ECU and a slave ECU.

"There's more than half a billion operations per second -- that's how much information per second goes to the ECU -- and the engine ECU is normally the master, except in launches when the gearbox ECU is the master."

The same electrical system controls the centre differential, which usually sends 70 per cent of the drive to the rear end, but can switch that instantly to 100 per cent (or zero) if required. It could, theoretically, send 100 per cent drive to the front, but the front diff is too small to handle that much torque...

Covering all of this is a bodyshell built for both speed and drama. Unlike the Murcielago, when the Aventador needs more air at higher speed it doesn't create more drag by opening a set of batwings. Instead, the Aventador uses active aerodynamics to open movable ducts in the side flanks for the oil cooler, while the higher side openings are purely to feed air into the engine.

There's a flat undertray to help the downforce at high speed and the rear wing also moves automatically. Reggiani insists it has negative lift at all speeds. It has three settings, dropping down to five degrees at very high speed and lifting to 11 degrees to help handling.

Inside, the Reventon's dalliance with TFT (thin-film transistor) instrument-cluster screens has paid dividends, because the Aventador has three of them in the dash alone (plus another for the MMI screen, mounted high on the centre of the dash.
This has allowed Lamborghini to provide all manner of information and options, including switching the speedo to a lower priority on the Corsa (track driving) mode so the driver can have a more prominent tacho.

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