Editing TVR Speed Twelve engine

{{Use dmy dates|date=August 2017}}
{{Use British English|date=August 2017}}
{{Refimprove|date=April 2018}}
{{Infobox engine
| name = TVR Speed Twelve engine
| manufacturer = [[TVR]]
| configuration = [[Naturally aspirated]] V12
| displacement = {{convert|7731|cc|L cuin|1|abbr=on}}
| block = Steel
| valvetrain = [[DOHC]] [[Multi-valve#Four valves|4 valves]] per [[Cylinder (engine)|cylinder]]
| compression = 12.5:1<ref name="Twelve"/>
| fuelsystem = [[Multi-point fuel injection]]
| fueltype = [[Petrol engine]]
| oilsystem = [[Dry sump]]
| coolingsystem = [[Water cooling (engines)|Water-cooled]]
| power = {{convert|880|bhp|PS kW|0|abbr=on}} at 7,250 rpm<ref name="Twelve"/>
| torque = {{convert|650|lbft|0|abbr=on}} at 5,750 rpm<ref name="Twelve"/>
}}
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.<ref name=Dodds>{{cite book|last1=Dodds|first1=Ralph|title=TVR: Cars of the Peter Wheeler Era|date=31 July 2015|publisher=The Crowood Press Ltd|isbn=978-1847979971}}</ref>

The engine was developed by essentially joining two [[TVR Speed Six engine|Speed Six]] engine blocks to a common crankshaft.  However it featured a revised cylinder head design with bucket valve actuation in place of the Speed Six's finger follower system.  The completed engine displaced 7.7 litres 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.

Unusually for an automobile, the Speed Twelve's engine block was not constructed of [[cast iron]] or [[aluminum]] [[alloy]], but rather of welded [[steel]] construction.<ref>{{Cite web |title=Birth of an Icon: TVR Speed 12 |url=https://www.evo.co.uk/features/10977/birth-of-an-icon-tvr-speed-12 |access-date=2022-09-20 |website=evo |language=en}}</ref>

The racing version of the engine produced approximately {{Convert|675|bhp|kW|0|abbr=on}} 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 {{Convert|1000|bhp|kW|0|abbr=on}}-rated [[dynamometer]] during the bench-test.  The engine's output was later estimated at {{Convert|960|bhp|kW|0|abbr=on}}, though the official figure given by TVR was {{Convert|800|bhp|kW|0|abbr=on}}.<ref name="Twelve">{{Cite web |last=D |first=Nick |date=2016-04-23 |title=2000 TVR Cerbera Speed 12 {{!}} Review |url=https://www.supercars.net/blog/2000-tvr-cerbera-speed-12-2/ |access-date=2022-09-20 |website=Supercars.net |language=en-US}}</ref>  When the prototype vehicle was road-tested by then-owner [[Peter Wheeler (TVR)|Peter Wheeler]], he reportedly concluded that the vehicle was too powerful to be practical and the project was scrapped.

==References==
{{Reflist}}

{{DEFAULTSORT:Tvr Speed Twelve Engine}}
[[Category:TVR engines|Twelve]]
[[Category:V12 engines]]