Only a very few Lamborghini Diablo VT were converted to Twin Turbo versions, actual numbers are not available but most sources state only 6 have been built originally.
These cars were actually very expensive and a rather rare find if you would like to purchase one. Years ago, Platinum Motors Ca. had one for sale, finished in black over a tan interior with red piping.
The original price was about $ 500.000, but for this amount of money you would get between 600 and 750 Bhp depending on turbo pressure, with a 0 to 60 mph time of only 3.2 seconds !
A very nice touch was a dash-mounted switch with three settings, one for valet use which limited the engine to about 3500 rpm, the second setting controlled a 6 psi boost delivering around 600 Bhp while the third one was a full 750 Bhp with 9 psi turbo pressure. All this led to a top speed of a healthy 358 Km/h. (222 Mph).
Twin blueprinted, water cooled, Garret T4 turbo's were installed with electronically controlled waste gates, custom built inter coolers, competition type valves with race-type guides and polished cylinder heads. A custom twin-plate clutch in Kevlar to cope with the extra torque, a new short ratio gearbox to improve acceleration, and reprogrammed electronic fuel injection system were used. Also the brakes were upgraded with cross drilled and ventilated disks using carbon fibre brake pads.
With all this power behind the drivers back, luckily the air conditioning system was upgraded too, just to keep your head cool enough to enjoy the brutal force of this unique kind of car.
The standard Diablo wheels became chromed and the bolts used for the three piece wheels were gold plated, just to get that extra touch when you park this exotic in the California sun.
One of the Twin Turbo's built was in fact a 1996 Diablo VT Roadster, the only Twin Turbo Roadster in the world until Gemballa made one too, this special VTTT Roadster was finished in red with a white leather interior, it was for sale at the beginning of 1999 at Platinum Motors.
A second hand Diablo VTTT will still cost about $ 380,000, if you can find one, because as far as I know only seven original VTTT were ever made.
The story behind the creation of the Diablo VTTT is quite interesting, the idea was to bore the standard 5.6-Liter out to a 7.4 Liter unit, but Automobili Lamborghini SpA didn't advice this move, instead it would be more feasible to use the 7.0 or even the 8.0 Liter marine engine from Lamborghini.
After close calculation this engine would pump out 640 Bhp with stock compression, but by installing two turbo's and boosting the compression, an easy 1170 Bhp was possible on dyno-testing, unfortunately this much power and torque would rip the Visco Coupling to pieces, so avoiding to rebuild a stronger coupling system, they settled for the standard engine and ended up with about 758 Bhp on the wheel dyno, unfortunately since the front axle drive was removed when testing the engine, about 20 percent would be lost driving the front wheels too, but still a healthy 600 Bhp would be available to the fortunate driver.
Another 'tuning' option was available for the early Diablo, the 'Stage II kit', which made the engine pump out about 100 Bhp more than normal, but this package didn't work on the later SE or SV type, only the early 2wd Diablo and the VT.
This 'factory official' package included special SV cam's, re-programmed ECM, Micron air filters and modified spark plugs, and best of all, these kits were factory approved because they were probably left-over units from an earlier attempt by Automobili Lamborghini SpA to enter racing, this means no warranty issues resulted from their installation in a Diablo still under factory warranty.
Later a lucky owner had his Diablo VT converted into a Twin Turbo car much in the same way as the original VTTT, but some major differences were apparent, the engine hood was taken from the SV model and the cylinder heads were heavily modified.
Probably the most important difference however was the fact that this 'seventh' VTTT was not an original Platinum Motors VTTT, the six VTTT were all built 'on special demand' for Platinum Motors, this seventh car wasn't ... but it still looked great and with about 850 Bhp (that's what the license plate says) it should have enough power to outperform a standard Diablo 6.0 VT.
The LamboCARS.com extensive specifications chart on Diablo VTTT VT Twin Turbo ...