The Story. Lamborghini Diablo History & Evolution
During its 11 years life, Diablo evolved gradually with several variants and updates, but overall the Diablo’s production dropped gradually each year.
The first derivative of Diablo was the VT, which stood for "Viscous Traction". It was simply the 4-wheel drive version of Diablo. A simple viscous coupling transferred power to the front wheels whenever the rear wheels slipped. This improved its wet weather handling a lot, although on the dry it suffered from some understeer. The 4WD hardware added about 50 kilograms.
The hottest Diablo in 1995 was SE30, which was a special edition for celebrating the 30 years anniversary of Lamborghini. Modifications included reducing weight by more than 220 lbs thanks to the use of magnesium wheels, carbon-fiber engine lid and rear spoiler, less equipment, thinner cabin trim and racing bucket seats. A revised engine management system increased output to 525 hp and with adjustable anti-roll bars and better cooling thanks to a new front bumper this Diablo was much better to drive. With only 150 units made, a very small portion received the "Jota" specifications tuning. Its V12 engine received variable intake ducts, variable exhaust, racing-style cams and a pair of ram-air intake at the roof, the latter would be carried over to the SV. Output was boosted too. Unfortunately the Jota did not comply with emission regulations in EU and USA.
The designation "SV" stood for "Super Fast" in English. It originally appeared in Miura P400 SV. By 1995, Lamborghini resurrected the name on a new Diablo. The Diablo SV was tuned to be more race car than roa car. Many magazines liked its firmer and crisper suspension setting, stronger brakes and shorter final drive which aided acceleration. They regarded it as the best handling Diablo even overshadowing the SE 30.
Bigger valves, faster cams and Jota-style ram-air intakes helped increasing power to 510 hp while a striped out cockpit helped reducing kerb weight to 1570 kg. As a result, the SV stood between SE30 and the standard Diablo in terms of power and weight. However, it was a lot cheaper than the SE 30 and even cheaper than the standard car, thanks to the short standard equipment list. Shorter final drive ratio led to the lowest top speed among all brothers, 186mph. Nevertheless, with the much improved handling, who cared about the nonsense top speed ?
In early 1998, Diablo SV was upgraded with an improved engine. The V12 gained a two-stage variable valve timing at inlet valves. Power increased to 530hp while torque was up from 428 lbft to 450 lbft. Moreover, the VVT enabled more torque at lower rpm, thus in-gear acceleration was much improved. Other improvements included bigger brake discs - 355mm up front and 335mm at the rear. As a result, larger 18-inch wheels were employed to accommodate the brakes. Besides, ABS and airbags were finally available to Lamborghini !
In 1999, the whole Diablo family received some minor modifications. Although engine and performance remained unchanged, there was a completely redesigned interior which featured a simpler instrument for easier reading. Passenger's airbag was added near the new glovebox. The only mechanical change was the addition of electronic adjustable dampers. All Diablos, including the standard Diablo, VT and Roadster, now shared the SV's variable valve timing engine. For SV, the "SV" sweeping graphics which used to be featured at the sides were deleted.
Being the street version of the GT2 race car, Diablo GT was the fastest ever Diablo and our favorite. The V12 was bored out to a full 6 liters. Accompanied with lightweight titanium connecting rods, faster-timing camshafts, individual throttle for each cylinder and enlarged ram-air intakes at the roof, power jumped while max torque increased too. The GT weighed 1490 kg in dry, 80kg lighter than SV. All body panels, excluding aluminium doors and steel roof, were made of carbon-fiber. In the engine compartment, intake manifolds were made of magnesium, which improved weight distribution to 40:60. Besides, Lamborghini also widened the front track by 110 mm, revised front suspension geometry, stiffened the springs and softened the dampers. The result was more high-speed stability and quicker turn-in at low speed. It was rare too, with only 80 units built.
Because the L147 project (which would become Murcielago) was being re-evaluated by new owner Audi, the Diablo had to receive one more update in year 2000 to fill the time gap. The 6.0 VT was the result. Audi designer facelifted the body, mainly in nose and tail. Now nearly the whole body was made of carbon-fiber panels, with the exception of aluminium doors and steel roof. Magnesium was used in cylinder heads, intake manifolds and the 18-inch wheels. Nevertheless, dry weight still went up to 1625 kg because of the compulsory 4WD and quite a lot of standard equipments.
The V12 was bored out to 6.0 liters, in addition to titanium connecting rods (from Diablo GT), lighter crankshaft, individual coil-on-plug ignition and two-stage variable exhaust (for complying noise regulation without losing power), it was conservatively rated at 550 hp and 458 lbft. Compare with GT, it didn’t have the ram-air intake on the roof (hence saving a rear-view camera) and hotter cam timing.
Like the GT, the 6.0 VT got wider tracks front and rear. In particular, there was 60 mm added to the front to improve turn-in response as well as stability. However, it didn’t steer as sharp as the lightweight SV, especially the viscous-coupling 4-wheel drive introducing quite an amount of understeer approaching the limit. In terms of performance, most road testers thought it was slower than the SV, blamed to extra weight it carried.
Interior was trimmed with carbon-fiber while position of pedals and gear lever were also improved a little bit. Undoubtedly, the final Diablo was the most friendly and the best built among all, thanks to the involvement of Audi.