TVR Cerbera Speed 12

The TVR Cerbera Speed 12, originally known as the Project 7/12, was a high performance concept car designed by TVR in 1997. Based in part on then-current TVR hardware, the vehicle was intended to be both the world's highest performance road car and the basis for a GT1 class endurance racer. However, problems during its development, changing GT1 class regulations and the eventual decision that it was simply incapable of being used as a road car ended the idea, forcing TVR executives to abandon its development.

The vehicle's engine, displacing 7.7 litres and having twelve cylinders, was reportedly capable of producing nearly one thousand horsepower, although an exact measurement was never made. Nonetheless, its performance was said to be astonishing, and it may have been capable of hitting sixty miles per hour in the low-three second range and have a top speed greater than that of the McLaren F1.

Project 7/12 concept
The vehicle, known as the TVR Project 7/12, first appeared at the 1996 Birmingham Motorshow and dominated the show once it was unveiled, attracting more crowds than any other cars in the show. The number "7" referred to the seven-point-seven litre (7.73 l) engine, and "12" for the number of cylinders in the engine. TVR said it would have over 800 bhp (600 kW) and be faster than the McLaren F1. The first concepts shown were based on in-development FIA GT1 class race car that was current at that time. It would be restricted to a more modest 660 bhp (490 kW) but the weight would be kept at roughly 1000 kilograms. The road car would weigh the same but without the restrictors, the power was greatly increased, TVR officially said it had 800 bhp (600 kW) but the real figure was never properly recorded. It had a specially built 6-speed manual transmission and clutch. The engine was essentially two TVR AJP6 straight-6 engines mated on a single crankshaft. Unusually for an automobile of its type, the Speed Twelve's engine block was not constructed of cast iron or aluminium alloy, but rather of steel.

Speed 12
By 1998 the car had been renamed the TVR Speed 12 and their GT1 racer was almost ready to go. TVR wanted to race at the 24 Hours of Le Mans, but that never happened. However, the Speed 12 GTS did manage to compete in a few races in the FIA GT Championship in the GT1 class, though sudden rule changes caused by advanced high-cost purpose built racers such as Porsche 911 GT1, Nissan R390 and Toyota GT-One and the subsequent demise of the class in other championships suddenly rendered the Speed 12 obsolete. In order that their work not go to waste, TVR immediately set about creating the road-going Speed 12, although the project would not be completed for another year.

Design-complete in 2000, the TVR Cerbera Speed 12, like its predecessor, never had a true measurement of engine power output officially taken, although the original engine (which produced 800 bhp) was employed yet again. The weight was kept down to 1000 kilograms and TVR reminded people that they were making a car that they thought would beat the McLaren F1 with the words "over 240 miles per hour" mentioned on several occasions. The new car would also be built in parallel with a new race car, although TVR were forced to opt for GT2 class as the GT1 class had been dropped some years previous. The new race car managed to run for a few seasons in the British GT Championship and had some success, winning several races. It did however have problems with reliability, often leading to the car retiring from races. Meanwhile, the road car was almost ready and TVR had taken a good number of orders and deposits for it. With a price of £188,000 it would be the most expensive TVR in history.

The racing version of the engine produced approximately 675 bhp (503 kW) with its power limited by the intake restrictors required by racing regulations. For the road-version of the engine, the restrictors were not needed so the engine was developed without them.

In an interview then-owner Peter Wheeler, said that TVR had tried to record the car's power on an engine dyno. The dyno was rated at 1,000 bhp (750 kW) but the test resulted in its input shaft being broken. To get an approximate figure TVR engineers tested each bank individually; the result was 480 bhp (360 kW) per bank, suggesting a total rating of 960 bhp (720 kW). Wheeler, no newcomer to high performance cars and an experienced racer in the TVR Tuscan Challenge, drove one of the finished prototypes home and concluded that the car was unusable on the road, in his opinion simply too powerful.

The deposits were returned when the production plans were cancelled. The remaining prototypes were carted around to various car shows and one by one they were dismantled and used as spares for the Speed 12 race cars still competing in the British GT championship. The life of the Speed 12 was however, not yet over. In August 2003 TVR placed an advert in Auto Trader for a TVR Cerbera Speed 12 registered W112 BHG. What TVR planned to do was to rebuild one of the prototypes and sell it on to an enthusiast. Buying the car was not a simple process however, and involved being personally met and vetted by Peter Wheeler himself to make sure the buyer was a suitable candidate for purchasing the car. Eventually, the deal was completed and the Speed 12 was rebuilt and handed over to its new owner. Since the original bodywork had been destroyed, TVR had to use a remaining shell from one of the GT racers, which proved a positive point as with the increased downforce the car would be even faster round a track than before. On top of that TVR did some more work on the engine and the ECU. The car featured in the May 2005 edition of Evo Magazine in which it was described as "awesome" and "terrifyingly quick".