The TVR Speed Twelve engine is the name of a V12 engine manufactured by TVR for use in the TVR Speed 12 race car, and later the TVR Cerbera Speed Twelve road car, neither of which ever went into production. A V12 engine is a V engine with 12 cylinders. ... TVRs logo TVR 280i TVR S series 1986 TVR 350i 1986 TVR Chimaera TVR Cerbera TVR is a manufacturer of sports cars, located in Blackpool in Lancashire, England. ... The TVR Speed 12 first appeared at the 1997 British motorshow. ...

The engine was developed by essentially joining two Speed Six engine blocks to a common crankshaft. The completed engine displaced 7.7 liters and was originally developed for racing applications in TVR's Speed Twelve. Later on, a version was developed for the prototype of a road car to be called the Cerbera Speed Twelve. The TVR Speed Six (also known as the AJP-6) is the name of a normally aspirated straight-6 engine manufactured by TVR by its TVR Power subsidiary in Coventry, England and used in several of their cars including the TVR Tuscan, TVR Cerbera, TVR Tamora and TVR Sagaris. ...

Unusually for an automobile, the Speed Twelve's engine block was not constructed of cast iron or aluminum alloy, but rather of steel. Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ... Alloy is a combination, either in solution or compound, of two or more elements, which has a combination of at least one metal, and where the resultant material has metallic properties. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ...

The racing version of the engine produced approximately 675bhp 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. According to reports from TVR engineers, the de-restricted engine snapped the central shaft of their 1000bhp-rated dynamometer during the bench-test. The engine's output was later estimated (conservatively) at 940bhp. When the prototype vehicle was road-tested by then-owner Peter Wheeler, he reportedly concluded that the vehicle was too powerful to be practical and the project was scrapped. A dynamometer, or dyno for short, is a device used to measure RPM and torque from which power produced by an engine or other rotating device can be calculated. ... Peter Wheeler (born 1945) is a chemical engineer from Yorkshire, UK, who owned the Blackpool-based TVR sports car company for 23 years. ...