Lamborghini's extraordinary new V12 powertrain
Lamborghini arguably kicked off the supercar segment in 1964 with its V12 350 GT and its high-revving V12 engines have been at the heart of the brand ever since, powering dreamcars such the Miura, Espada, Countach, Diablo and Murciélago. Now it has released details of its next 6.5 litre V12 powerplant – as you’d expect, it’s compact, light and with a lower centre of gravity, not to mention brutally powerful (700 bhp) but the raw numbers, as remarkable as they are, do not do it justice. For starters, the 48 valves are actuated electronically, enabling things you just can’t do with camshafts to create a well-rounded torque curve topping out at 690 Nm.
Very few cars managed to change the automobile world like the Miura. With its central engine and fascinating body designed by Marcello Gandini for Bertone, in 1966 Lamborghini redefined the concept of Super Car
The sophisticated engine management, thermal management and oil circulation management systems ensure absolute engine health under extreme conditions. The intake system incorporates four throttle valves and the optimum intake path for any given load and engine speed is facilitated by two flaps, several channels and one bypass while the exhaust system also combines high and low volume mufflers in stages, and the full glorious acoustics can be optimized for the circumstance. You can bet the farm this masterpiece will win Engine of the Year and the new seven-speed “emotional” ISR (Independent Shifting Rod) robotized servo-actuated transmission is equally as impressive, further illustrating an all-encompassing innovation process.
The new 525 kW twelve-cylinder engine was developed from a “clean sheet” and perfectly complemented by a completely new transmission concept for super sports cars: The “Lamborghini ISR” automated manual gearbox combines minimal shift times to “guarantee the emotional gearshift that customers expect from a super sports car at the very top of the premier league”. The new powertrain will enter production early in 2011, initially to power the Murciélago replacement and subsequently the next generation of V12s.
Lamborghini believes the 12 cylinder configuration is perfect for the 6.5 litre class of supercar, while ten cylinders are ideal in the five liter displacement class. “A lower number of cylinders would result in larger and heavier pistons and con-rods, which would have a negative impact on the engine’s high-revving characteristics,” explains the official announcement. The specification for the development of the new twelve-cylinder, known internally as the L539, specified that it had to deliver more power and torque than its predecessor in the Murciélago, but it should also be smaller and lighter and enable a lower center of gravity. At the end of the day, low weight is just as important to the performance of a super sports car as high power output. Fuel consumption and gas emissions were also stipulated, “to be reduced significantly”.
The resultant 60 degree V12 measures 665 millimeters from top to bottom, including the intake system. Its width, including the exhaust manifold, is only 848 millimeters, while its length is a mere 784 millimeters. Its weight of 235 kilograms is also respectably low – each kilogram of engine weight corresponds to 3.0 HP maximum output.
The crankcase is made from an aluminum-silicon alloy and has an open-deck construction with steel cylinder liners. Displacement is 6,498cc from a bore diameter of 95 millimeters and a stroke of 76.4 millimeters. The short-stroke layout is especially good for high-revving characteristics and for low internal friction. Particular attention was also paid to the bearings for the forged and nitride-hardened crankshaft, which weighs in at 24.6 kilograms.
The two four-valve cylinder heads are likewise made from sand-cast aluminum-silicon alloy, each weighing a very light 21 kilograms. The twelve pistons and con-rods are, respectively, in forged alloy and steel. The maximum piston speed at 8,250 rpm is only 21 meters per second, which is considerably less than for the current Murciélago power unit. The combustion chambers were carefully engineered to achieve optimum tumble and combustion of the fuel/air mixture which is then compressed at 11.8:1.
Sophisticated thermal management, optimized oil circulation
The thermal management system has two switchable water circuits to ensure very rapid warm-up, which minimizes friction and quickly brings the catalytic converters up to operating temperature, thus benefiting fuel consumption and emissions. The external water coolers are switched into the circuit only as required.
Absolute engine health, even under extreme racetrack conditions with high lateral acceleration, is guaranteed by oil circulation using a dry sump system. A total of eight scavenger pumps suck oil out of the lower bedplate fastened to the crankcase. Pressure and scavenging losses are thus reduced by around 50 percent.
A high-pressure oil pump maintains lubrication, while an oil/water cooler and an oil/air radiator constantly keep temperatures within range even under extremely high load. A further benefit of this form of dry sump lubrication is the very low mounting position of the engine within the sports car. The new engine is mounted 60 millimeters lower than the V12 in the Murciélago, with obvious benefits in lowering the center of gravity of the car, and improving lateral dynamics.
From the outside, the V12 is dominated by its intake system – which incorporates four individual throttle valves. Life inside the black housing is also extremely complex – the optimum intake path for any given load and engine speed is facilitated by two flaps, several channels and one bypass. The payback is an extremely well-rounded torque curve and refined pulling power throughout the rev range.
Acoustics – a mighty orchestra for twelve voices
The exhaust system also came in for considerable attention from Lamborghini’s engineers – the lowest possible gas emissions was deemed equally (well, almost), as important as the unmistakable Lamborghini sound. The hydro-formed and thermally insulated three-into-one system incorporates four pre-catalytic converters close to the engine and two main catalytic converters shortly before the muffler.
The casing incorporates two separate mufflers – one low-volume, one high-volume. Regulated by valves controlled via the engine management, they handle all the elements of the big twelve-cylinder symphony – from a moderate rumble when rolling through the city at low revs to the screaming crescendo of maxed-out gear shifts.
Electronics entirely by Lamborghini
The electronic engine management was developed entirely in-house consisting of the main ECU, secondary “smart actuators” and two additional black boxes that function as “smart sensors”. Because speed is paramount in an engine such as this, some ECU control and connection functions are handled by the smart actuators, making the ECU faster. The two smart sensors constantly monitor each and every combustion in every cylinder in real time. The spark plugs, each powered by an individual ignition coil, function as “sensors”; the two auxiliary control units monitor the power signal after every ignition and can immediately identify irregularities in the combustion process through ionization phenomena. This data is used to continually optimize engine management, benefiting both performance and fuel consumption.
High performance in every dimension
The technological masterpiece in its initial specification will have a maximum output of 515 kW (700 hp) at 8,250 rpm while maximum torque of 690 Newton meters is available at 5,500 rpm. The extremely generous torque curve, meaty pulling power in every situation, extremely reflexive responses and, not least, the finely modulated but always highly emotional acoustics make the L539 a stunning power unit for a super sports car of the highest order. The entire L539 engine was developed and will also be built in-house at Lamborghini in Sant’Agata Bolognese. All engines are assembled by hand, with every unit undergoing extensive final testing and detailed calibration program on an engine test bed.
Matching engine and transmission
The character and driving characteristics of a super sports car are not solely the domain of the powerplant. The transmission is critically important in the overall driving equation. The ratios must be perfectly arrayed and enable optimum power delivery from the engine.
For maximum vehicle performance, shift times should be less than the blink of an eye. Operation must be clear and straightforward, via two ergonomic shift paddles behind the steering wheel. The characteristics of the transmission must be in line with the wishes of the driver at any given point – from smooth city cruising through to uncompromising performance on the racetrack.
Most importantly, Lamborghini customers expect an emotional shift feeling that ensures the sports car’s reactions can always be felt and understood. Thus, the development objective was clearly formulated in this respect, too – create the world’s most emotional gear shift.
The ingenious Lamborghini ISR transmission
For all these reasons, the engineers in the R&D Department opted for a robotized gearbox as the “companion” of the new V12 power unit – however, in a very special iteration: the Lamborghini ISR transmission. This robotized gearbox combines extremely fast shift times (almost 50% less than dual-clutch transmission) with the benefits of a manual transmission in terms of weight and compact dimensions – both always critical for super sports cars.
The new unit is laid out as a two-shaft transmission with seven forward gears and one reverse. For especially high durability, the synchronizing rings are made from carbon-fiber – a material with which Lamborghini has enormous experience. The short shift times are facilitated by the special design of the transmission, known as ISR – Independent Shifting Rod.
To summarize the principle – in a conventional manual gearbox, be it automated or fully manual, the gear wheels for, say, second and third gears are located side by side. When the driver wants to shift gear, the shifting sleeve with synchronizer unit is moved along the shifting rod from second gear through neutral to third gear. This requires twice the distance and twice the time – second gear has to be disengaged before third gear can be engaged.
This process is significantly shortened in the Lamborghini ISR transmission – the gear wheels from the second and third gears are separate from each other and the shifting sleeves are actuated by independent shifting rods. Now the shifting process can run virtually in parallel – while one shifting rod is disengaging one gear, the second shifting rod can already engage the next gear. Because these movements partially overlap and the mechanical distances are considerably shorter, this facilitates a significant saving in shift time.
Overall, the Lamborghini ISR transmission shifts around 40 percent faster than the e.gear transmission in the Gallardo, already one of the world’s fastest automated manual gearboxes.
Compact construction, low weight
The new transmission has four of these independent shifting rods, with sensors constantly monitoring their exact positions. They are operated via hydraulic actuators, with an extremely high system pressure of 60 bar ensuring the necessary operating speed. The system incorporates a total of seven hydraulic valves, with pressure supplied by an electric pump. The double-plate clutch is also hydraulically actuated. All system components are contained within one casing. The total weight of the transmission is only 70 kilograms – a distinct advantage, especially compared with the significantly heavier dual-clutch transmissions from the same category.
Three operating modes for all situations
Lamborghini drivers can choose between three operating modes – the Strada mode offers highly comfort-oriented shifting, with fully-automatic also an option. The Sport mode has a dynamic set-up in terms of shifting points and times, while the Corsa mode delivers the maximum shift strategy for race track driving. This mode also includes Launch Control, the automatic function for maximum acceleration from a standing start.
With the Lamborghini ISR transmission, engineers working under the sign of the bull have devised an ingenious mate for the new twelve-cylinder power unit. Their work has created an overall powertrain that is absolutely unique in the world of super sports cars.
Integrated electronic control system
The excellent performances are possible only by a fast communication architecture through the several powertrain ECU’s and considering the powertrain as ONE-system (un unico sistema) in the car. The fully electronic controlled coupling device for the front wheels (the ‘old’ viscous coupling) is another key point of the powertrain: it is able to continuously distribute the right torque to the front wheels for always attaining the best performance aspired to by the driver. The torque distribution to the front wheels can vary continuously from 0% to 60% of the total torque available.
The twelve-cylinder heart of the bull
Lamborghini V12 – that means a long and glorious story. According to the history books, Ferruccio Lamborghini established a car company in the early sixties because he wanted to better the products on offer at the time from the competition, with the best possible technology and quality.
The prototype for all later Lamborghini super sports cars was the 350 GTV study presented at the Turin Motor Show in 1963.
It featured an all-new aluminum twelve-cylinder developed from scratch by engine designer Giotto Bizzarini and boasted performance figures that were nothing short of breathtaking by the standards of the time. The 12-cylinder V-engine with 60 degree cylinder bank angle, four overhead camshafts (at a time when single camshafts were still the norm), a six bbl carburetor and dry-sump lubrication, generated 360 hp at 8,000 rpm from a displacement of 3,497cc that would take the concept car to a top speed of 280 km/h. The 350 GT series production version with conventional lubrication, launched the following year, produced 320 hp at 7,000 rpm from a displacement of 3,464cc.
It was exactly this engine that captured the imagination of show-goers at the 1966 Geneva Auto Salon in the Lamborghini Miura. Although its main features were already familiar from the 400 GT, this time the four-liter 60° twelve-cylinder was mounted transversely behind the cockpit, with transmission and differential in a single unit fixed directly to the frame. The 320 hp made the series production Miura that followed the fastest production car of its time with a stated top speed of more than 280 km/h – and, with that, the first true super sports car.
This engine was further developed over the years, with several iterations featuring in the Miura S (370 hp at 7,000 rpm, 285 km/h) and Miura SV (385 hp, 300 km/h). In the Miura Jota, a one-off made for racing, the V12 generated 440 hp at 8,500 rpm. However, applications for the four-liter were not limited to the mid-engine Miura.
In the front-engine Islero, introduced in 1968, and in the 400 GT Jarama, it produced 350 hp, while in the futuristic Espada the figure was 325 hp (later also 350 hp). In 1974, the Espada also saw an automatic transmission offered for the first time. The generational shift from the Miura to the new LP400 Countach took place in the early seventies. 1971 brought the prototype with a breathtaking, edgy form, the genes of which would ultimately re-emerge forty years later in present-day Lamborghini super sports cars. Marcello Gandini’s design was a fitting outfit for a five-liter version of the V12.
However, this engine was dropped from the series production model in 1973 in favor of a further evolution of the four-liter unit. In the 1973 Countach – still without the “wing” or spoiler of the eighties – it was longitudinally mounted behind the driver, where it generated 375 hp at an impressive 8,000 rpm and reached a top speed of 300 km/h.
The years that followed saw the Countach engine undergo a series of evolutionary developments, although still based on the familiar cornerstones of the first V12 unit. It was in 1985 that the Countach Quattrovalvole took displacement over the five-liter mark for the first time (5,167cc) and as the name implies, featured a four-valve cylinder head. Output was an impressive 455 hp at 7,000 rpm.
In 1986, the five-liter V12 was presented with a completely new application – the Lamborghini LM002 may also have had the 450 hp engine mounted up front, but the 2.7 ton automobile was the first and only SUV produced by the brand, a four-door all-terrain vehicle.
The late eighties saw the amazingly long career of the Countach near its end with the Countach Anniversario.
The Diablo followed as its rightful heir, clad in a distinctly nineties outfit. By 1990, the V12 had grown to almost six liters and produced 492 hp. One year later, the Diablo VT was the brand’s first four-wheel drive sports car. Over the next few years, output grew steadily to 520 hp (1993 Diablo SE).
The Diablo GT with 575 hp and the radical GTR with 590 hp both appeared in 1999. The Diablo 6.0 was the first model to feature the V12 with displacement expanded to six liters, its output ultimately reaching 550 hp. The Murciélago was launched in 2001 as the first Lamborghini of the new era. It boasted a new 6.2 liter alloy V12 with a crankshaft running on seven bearings and dry-sump lubrication. It generated 580 hp at 7,500 rpm and took the super sports car weighing just 1,650 kilograms to a top speed of 330 km/h. The maximum torque of 650 Nm was reached at just 5,400 rpm.
At the 2006 Geneva Motor Show, Lamborghini unveiled the Murciélago LP 640, which produces 640 hp from the V12 unit that had been expanded to 6,496 cc
In the strictly limited Lamborghini Reventón, the twelve-cylinder that is the very heart of the brand generated 650 hp. The grand finale came with the Murciélago LP 670-4 Superveloce with its 670 hp.
The first quarter of 2011 will mark the beginning of a new chapter in the glorious story of Lamborghini’s V12s.