- Two Other Lambos Have Had A Rear Transverse-Mounted Gearbox
- What’s Special About A DCT?
- Why Did Lambo Put The Gearbox Behind The Engine?
- Compact Dimensions
- Genius Electric Motor Integration
What other Lambos featured a similar configuration? And why does it even matter?
The 2024 Lamborghini Revuelto is the start of a new era for the Raging Bull, not just one of electrification in a traditional sense, but through a plethora of firsts – the first 1,000-horsepower Lambo, the first Lambo V12 with a DCT, the first super sports car with a 100% carbon fiber front structure. But the gearbox is the most important.
Not only is it the first time a Lamborghini V12 has been paired with a wet-clutch DCT, but the gearbox is positioned transversely and on the rear of the engine instead of in front of it. This unique layout is not a first for the brand, with two bull-branded supercars having wielded the design before, but it is of crucial importance when looking at the technological marvel of this 1,001-hp brute.
Two Other Lambos Have Had A Rear Transverse-Mounted Gearbox
Lamborghini's 60-year history has been intricately entwined with the V12 engine, but only twice before the Revuelto has there been a transverse rear gearbox. The iconic Lamborghini Miura used it for the first time back in 1966. The Miura was a Lambo of firsts, too, and is, as far as this author can find, the only transverse mid-mounted V12 in history. In this instance, the V12 was packaged to include an integrated transmission and differential because of the space constraints of the tiny supercar.
The only other Lambo to utilize the concept was the Essenza SCV12, a limited-edition track-only supercar. Because it was purely motorsport-focused, it eschewed the Aventador's automated manual transmission in favor of a sequential Xtrac 'box. It was transversely mounted at the rear of the engine as a load-bearing element of the car's chassis.
What’s Special About A DCT?
It's the first DCT in a V12 Lambo, and that alone is notable. The Aventador managed to remain contemporary despite its many years on the market but was let down by the uncouth nature of its single-clutch automated transmission. But Lamborghini didn't just slap on the DCT from the Huracan and call it a day. No, it developed a bespoke eight-speed unit that could cope with the rigors of a 1,001-hp tri-motor hybrid hypercar.
The benefits of going DCT are numerous, but the most important, arguably, is that a DCT can upshift with no torque interruption. Instead of letting off the throttle or retarding spark to smoothen gear changes, a DCT can engage the upper gear simultaneously and then simply declutch the lower gear, letting power flow without interruption. On top of this, a DCT is compact, with only two primary shafts compared to the three of the old layout. One shaft manages odd gears and the other manages even ratios.
The DCT also enables 'continuous downshifting.' This principle entails the driver holding the downshift paddle resulting in the car dropping multiple gears under braking, engaging the lowest possible gear for the engine speed.
Why Did Lambo Put The Gearbox Behind The Engine?
The greatest inventions often arise out of necessity, and in this case, Lamborghini needed to find somewhere to position the battery pack – this is a hybrid, after all. No matter how compact they are, batteries are dense items that weigh more than their dimensions may suggest, so the placement of the 3.8 kWh lithium-ion battery pack would greatly impact the weight distribution and handling characteristics of the Revuelto. The solution, then, was to place it as close to the center of the car as possible, enabling a 44:56 weight distribution ratio.
In what is commonly termed the transmission tunnel – and what has been the transmission tunnel of a Lamborghini since the days of the original Countach – you'll now find said battery pack, which measures 61 inches long, 11.85 inches tall, and 9.45 inches wide.
But if the battery is in the middle, then Lamborghini had to find somewhere else to put the transmission. This could have been integrated as a transverse unit in front of the engine, which would have provided better weight distribution, but in doing so, Lamborghini would have compromised the space in the supercar's cabin, which is more spacious than the Aventador Ultimae it replaces. So Lamborghini got creative and mounted it behind the engine, while its transverse nature and compact dimensions mitigated its impact on weight distribution.
Compact Dimensions
Speaking of its impact on weight distribution, the all-new transmission is tiny, relatively speaking. 22 inches long (from front to rear), 29.5 inches wide, and just 22.8 inches high, it doesn't occupy much space at all, and the space it does take up is across the transverse plane rather than a longitudinal one, helping center the powertrain's weight within the wheelbase.
The short nature of the DCT (front-to-rear) also enabled Lamborghini to fit a proper working diffuser to the car without having to lengthen the bodywork unnecessarily.
It's also relatively light at just 425.5 lbs, including the weight of an integrated electric motor. For reference, Koenigsegg's Light Speed Transmission defies logic at 198 lbs, while the eight-speed DCT Ferrari sources from Magna for the SF90 Stradale weighs 305.3 lbs, without the added electric motor weight Lamborghini includes in its figures. Lamborghini claims that without the electric motor, the new transmission is faster and lighter than the Dana-sourced seven-speed in the Huracan, which weighs only 311 lbs.
Genius Electric Motor Integration
The electric motor that operates alongside the DCT is big news. Traditionally, manufacturers will sandwich a motor between the transmission and the engine which operates as an integrated starter-generator and feeds extra torque into the drive system, but Lamborghini's unique positioning of this 110 kW (147.5 hp) and 110.6 lb-ft motor necessitated special integration. The electric motor can decouple itself from the wheels or from the engine, resulting in multiple ways in which it can be used.
The electric motor has a dedicated coupling system and synchronizer that enables it to connect directly to the DCT itself and feed power into the system. This is how you get the full gamut of 1,001 hp in one go in Performance mode. But it can also operate outside of this state (P1).
In P2 state, the electric motor becomes a generator, harvesting energy from low-speed driving to recharge the battery. It's also in this state that it doubles as the starter motor.
The final position is P3, connecting independently to the rear wheels with no integration of the engine. In this state, the Revuelto combines the two front motors and the rear motor above the gearbox to create pure-electric four-wheel drive, resulting in traction from its electric drive modes that other hybrid supercars that rely on the front motors simply don't have.
Theoretically, the Revuelto is capable of 442.5 hp in all-electric guise, and while the rear motor isn't typically engaged in reverse (which is handled primarily by the front electric motors), it can be brought into the fray for additional momentum.
Keyword: Everything You Need To Know About The Lamborghini Revuelto's Rear Transverse Gearbox