TVR Speed Eight engine
{{Use dmy dates|date=July 2017}}
{{Use British English|date=July 2017}}
{{Infobox engine
| name = TVR AJP8 Engine
| image =
| caption =
| manufacturer = TVR
| aka =
| production = 1996 – 2003
| predecessor =
| successor = TVR Speed Six engine
| configuration = 75° flat-plane V8{{cite web|url=http://www.tvr-eng.co.uk/cerbera.html|title=The Official TVR Website|access-date=26 November 2022|archive-url=https://web.archive.org/web/20000617160038/http://www.tvr-eng.co.uk/cerbera.html|archive-date=17 June 2000}}
| displacement = {{convert|4185|cc|cuin|0|abbr=on}}
{{convert|4475|cc|cuin|0|abbr=on}}
| bore = {{convert|88|mm|in|1|abbr=on}}
{{convert|91|mm|in|1|abbr=on}}
| stroke = {{convert|86|mm|in|1|abbr=on}}
| block = Aluminium alloy
| head = Aluminium alloy
| valvetrain = SOHC 2 valves x cyl.
| timing =
| compression = 10:1,10.75:1
| operating principle =
| supercharger =
| turbocharger =
| turboboostpressure =
| fuelsystem = Port fuel injection
| management =
| fueltype = Petrol
| oilsystem =
| coolingsystem = Water-cooled
| idle =
| redline =
| power =
| specpower =
| torque =
| length =
| width =
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| weight =
| emissions level =
| emissions control =
}}
The AJP V8 is a naturally-aspirated V8 car engine designed by Alwyn Melling of the design consultancy MCD, and manufactured for road legal cars production (TVR introduced the Cerbera at the 1993 London Motor Show), from 1996 to 2003. The engine was intended to power the TVR Griffith and the TVR Chimaera, but delays in its production meant that it powered only the TVR Cerbera and, from the 1990 year, as strong performance and reliability testing development up to production, the TVR Tuscan Challenge race car in 4.5 litres version. {{cite web|url=https://www.hagerty.com/media/hagerty-marketplace/its-namesake-guarded-the-gates-of-hell-but-this-96-tvr-is-a-v-8-ticket-to-paradise/|title=Its namesake guarded the underworld, but this TVR Cerbera is a ticket to paradise|first=Adam|last=Wilcox|publisher=Hagerty Media|date=10 August 2022|access-date=26 November 2022|archive-date=26 November 2022|archive-url=https://web.archive.org/web/20221126075032/https://www.hagerty.com/media/hagerty-marketplace/its-namesake-guarded-the-gates-of-hell-but-this-96-tvr-is-a-v-8-ticket-to-paradise/|url-status=live}} It was first engine offered by TVR that was both designed and built in-house.{{cite web|url=https://www.carthrottle.com/post/what-makes-the-mental-tvr-cerbera-a-proper-90s-hero-car/|title=Why The Crazy TVR Cerbera Is A Proper 90s Hero Car|first=Graham|last=King|publisher=Car Throttle|access-date=26 November 2022|archive-date=26 November 2022|archive-url=https://web.archive.org/web/20221126075037/https://www.carthrottle.com/post/what-makes-the-mental-tvr-cerbera-a-proper-90s-hero-car/|url-status=live}} The reason behind the engine's development and production was that Rover, after previous announcements, was bought by BMW in 1994, and Peter Wheeler, the owner of TVR at the time, feared that BMW would drop the Rover V8 engine used in TVRs since the early 80's. Wheeler contracted Al Melling to design a brand-new V8 engine to power the TVR Cerbera that TVR could also sell to other car manufacturers. TVR ceased manufacturing the design when the Cerbera was discontinued in 2003.
The engine was developed by Melling, John Ravenscroft and Peter Wheeler. Its production code-name was "AJP8" (A=Al, J=John, P=Peter); this naming convention was subsequently used for the Speed Six engine's "AJP6" code-name. The AJP V8 featured many aspects found in a racing engine, such as a flat plane crankshaft, a 75-degree angle between the cylinder banks,{{cite web|url=https://www.roadandtrack.com/car-culture/a25685083/the-tvr-cerbera-used-a-truly-strange-v8/|title=The TVR Cerbera Used a Truly Strange V8|first=Chris|last=Perkins|work=Road and Track|location=US|date=18 December 2018|access-date=25 November 2022|archive-date=25 November 2022|archive-url=https://web.archive.org/web/20221125063730/https://www.roadandtrack.com/car-culture/a25685083/the-tvr-cerbera-used-a-truly-strange-v8/|url-status=live}} a SOHC arrangement operating two valves per cylinder, and sequential fuel injection.{{fact|date=November 2022}}
Two versions of the AJP V8 engine were offered by TVR on the Cerbera Road car: one, displacing 4.2L and producing {{convert|360|bhp|kW PS|abbr=on}}, and the other displacing 4.5L and producing {{convert|420|bhp|kW PS|abbr=on}}. A Red Rose conversion was made available that increased output to {{convert|440|bhp|kW PS|abbr=on}} when using fuel with a minimum octane rating of 97 RON. The Red Rose upgrade included reshaped intake and exhaust ports, higher compression, and an ECU that can be switched between two sets of fueling and ignition maps (for 95 RON and 97 RON fuel, respectively).{{cite web|url=https://www.tvr-car-club.co.uk/tvr-cerbera.html|title=TVR Car Club - TVR Cerbera Details|access-date=25 November 2022|archive-date=25 November 2022|archive-url=https://web.archive.org/web/20221125063732/https://www.tvr-car-club.co.uk/tvr-cerbera.html|url-status=live}}
The AJP V8 engine had a high specific output for a normally aspirated engine at the time, with 83.3 bhp/L for the 4.2L, 93.3 bhp/L for the 4.5L, and 97.7 bhp/L for the Red Rose-specification 4.5L engine. Another notable aspect is the weight of the engine, which is {{convert|121|kg|lb|abbr=on}} dry.{{cite web|url=https://www.tvrblog.com/tvr-speed-eight-engine/|title=TVR: The AJP8 engine|first=Alvise Marco|last=Sena|date=1 March 2008|access-date=25 November 2022|archive-date=25 November 2022|archive-url=https://web.archive.org/web/20221125063736/https://www.tvrblog.com/tvr-speed-eight-engine/|url-status=live}}