It took one full-throttle upshift into 4th gear while tracking away from an apex to remind us that the 2012 Lamborghini Aventador LP700-4 is a monster. The gear slams home with such authority that the ass end instantly jerks sideways a couple of feet before the Aventador can scramble the appropriate countermeasures to prevent its V12's avalanche of power from having its way with the car's carbon-fiber chassis, huge tires and the surrounding countryside.

With the Aventador, Lamborghini has an all-new range-topping supercar to replace its aging Murcielago. It's big, outlandish and powerful. In other words, it's a typical Italian supercar.

There's a new wrinkle here, though — the Aventador is a pussycat. A 690-horsepower pussycat that will tear to 62 mph (100 km/h) in 2.9 seconds, reach 124 mph (200 km/h) 6 seconds later and rip off 10.5-second quarter-miles.

An All-New 12-Cylinder Engine

Italian supercars and V12s go together like grappa and food comas, so naturally the Aventador (say ah-vent-ah-DOR) mounts a hand-built, normally aspirated bent-12 longitudinally between the rear wheels and the cabin. That's where the Aventador get its LP (Longitudinale Posteriore) designation.

Known internally as L539, it's a clean-sheet power unit that shares nothing with the outgoing power plant beyond its 6.5-liter displacement. Variable phasing of the intake and exhaust cams facilitates a compression ratio of 11.8:1, quite high for an engine that doesn't use direct injection (DI). Engineers say DI was ruled out due to upcoming European regulations for particulate emissions, which would have required a particulate filter and an associated penalty in exhaust backpressure. Besides, the performance targets were met without DI, so why bother?

L539 is a deceptively conventional engine elsewhere, too, with forged steel connecting rods instead of the titanium that's all the rage and steel sleeves in lieu of whatever unicorn tears are sprayed onto the cylinder walls of other modern engines. However, it's hard to argue with the results.
Its numbers are staggering — peak power of 690 hp is reached at 8,250 rpm and its maximum 509 pound-feet of torque arrives at 5,500 rpm. Dry-sumped, short-stroke 12-cylinder layouts lend themselves to high revs and breathing — 48 valves provide an enormous valve curtain area, and each piston and rod can be relatively puny, reducing reciprocating forces in the bottom end.

Despite its absurd power, the engine is said to weigh just 518 pounds and stands nearly 3 inches lower than the old V12 to keep the center of gravity in check.

Sharp and tractable at low revs, yet devastatingly powerful, it's a gem of an engine. The combination of its flat, broad torque curve and terrific reach results in velocity that piles on deceptively quickly. The lazy sound of the engine, too, is tricky. Three-thousand rpm sounds like idle, and the 8,500-rpm redline — which comes up in a hurry — is devoid of aural urgency: a tenor wail with a dash of flat-6 drone. As a result you find yourself traveling much faster than you expect when it comes time to visit the carbon-ceramic brake department, which, fortunately, offers ample fade resistance.

New Seven-Speed Gearbox and AWD System

Appropriately, the new engine is mated to a new transmission and all-wheel-drive system. The transaxle houses a new single-clutch seven-speed automated manual gearbox and a Haldex IV clutch pack that replaces the viscous coupling center differential of the Murcielago.