Editing Cosworth (section)

==={{anchor|YB|YBB|YBD|YBJ|YBG|YBT|YBP}} The YB series===
[[File:Ford Cosworth YB engine (2015-01-01) 01.jpg|thumb|YB engine]]
The YB series of {{convert|1993|cc|1|abbr=on|lk=on}} engines are based on the older [[Straight-four engine|inline four]] [[Ford Pinto engine|Ford T88 engine block]],<ref name=Moreton>{{Citation | title = Rallye Sport Fords – the inside story | author = Moreton, Mike | date = 15 November 2007 | isbn = 978-1-84584-115-7}}</ref> and were introduced in the road-going [[Ford Sierra RS Cosworth]] in 1986 with {{convert|204|PS|kW bhp|0|abbr=on|lk=on}}. With 5,000 units built for homologation purposes in [[Group A]], both for rallies and touring cars. Racing versions of the RS Cosworth were developing around {{convert|370|hp|kW PS|0|abbr=on}},<ref>{{cite web|url=http://touringcarracing.net/Pages/1987%20Cars.html|title=1987 WTCC Cars index|website=touringcarracing.net|access-date=5 July 2017}}</ref> but with the small Garrett T3 turbo on the cars reliability was a problem. A limited edition evolution model was introduced in mid-1987 (once the base of 5,000 cars had been built, only 500 "evo" or upgraded versions were needed for Group A homologation), the [[Ford Sierra RS500|Sierra RS500]] which included a bigger T4 turbo, with power initially at around the {{convert|470|hp|kW PS|0|abbr=on}} mark in 1987, but in later years climbing to close to some {{convert|550|hp|kW PS|0|abbr=on}} in full racing trim.

The RS500 came to dominate [[touring car racing]] in its heyday from 1987 to 1992, winning multiple championships and major races.<br>

'''Championship wins'''
* [[World Touring Car Championship]] – [[1987 World Touring Car Championship|1987]] (<small>Entrants title</small>)
* [[Japanese Touring Car Championship]] – 1987, 1988, 1989 (<small>1989 Entrants title</small>)
* [[Australian Touring Car Championship]] – [[1988 Australian Touring Car Championship|1988]], [[1989 Australian Touring Car Championship|1989]]
* [[European Touring Car Championship]] – 1988 (<small>Entrants title</small>)
* [[Deutsche Tourenwagen Meisterschaft]] – [[1988 Deutsche Tourenwagen Meisterschaft|1988]]
* [[Amaroo Park|AMSCAR series]] – 1988, 1989, 1990
* Nissan Mobil 500 Series – 1989, 1990
* [[New Zealand Touring Car Championship]] – 1989, 1990, 1992
* [[British Touring Car Championship]] – [[1990 British Touring Car Championship|1990]]

'''Major race wins'''
* [[Wellington 500]] – [[1987 Wellington 500|1987]]
* [[Fuji Speedway|Fuji InterTEC 500]] – [[1987 Fuji InterTEC 500|1987]], 1988, 1989
* [[RAC Tourist Trophy]] – 1988
* [[Sandown 500]] – [[1988 Enzed 500|1988]], [[1990 Sandown 500|1990]]
* [[Bathurst 1000]] – [[1988 Tooheys 1000|1988]], [[1989 Tooheys 1000|1989]]
* [[Pukekohe 500]] – 1988, 1989, 1990
* [[Spa 24 Hours]] – 1989
* [[Guia Race of Macau]] – 1989

The only car to truly challenge the Sierra's power dominance towards the end of the Group A era in 1990–1992 was the {{convert|640|hp|kW PS|0|abbr=on}}, [[4WD]] twin turbo [[Nissan Skyline R32 GT-R]].

At the end of its life in Group A in 1992, the Australian Sierra teams were reportedly getting around {{convert|600|bhp|kW PS|0|abbr=on}} from the 2.0L turbocharged YB engines. For his pole position lap at the [[1992 Bathurst 1000]], Australian driver [[Dick Johnson (racing driver)|Dick Johnson]], whose [[Dick Johnson Racing|team]] since 1988 had a reputation for having the fastest Sierras in Group A racing anywhere in the world, was reportedly running a special qualifying engine and F1 level fuel supplied by the team's major sponsor [[Shell plc|Shell]] (consisting of a mix of [[Toluene]] and [[Methanol]]). His YBD engine for the Top 10 Runoff at Bathurst was rumoured to be producing up to {{convert|680|hp|kW PS|0|abbr=on}}.

The various colour cam covers that distinguished each version were as follows:
* Red: '''YBB''' (Sierra Cosworth 2wd, both 3-door and Sapphire), '''YBD''' (Sierra RS500), '''YBJ''' (Sierra Sapphire 4wd, non cat)
* Green: '''YBG''' (catalyst equipped 4x4 Sierra Sapphire Cosworth)
* Blue: '''YBT''' (large-turbo Escort Cosworth)
* Silver: '''YBP''' (small-turbo Escort Cosworth).

Further evolutions of the YB included a reduced-emissions road version, as well as the block used in the [[Ford Escort RS Cosworth|Escort RS Cosworth]] (which used the Sierra floorpan). The engine stopped being used on new cars in 1997, with the [[Ford Focus (International)|Focus WRC]] and road-going Focus RS instead relying on [[Ford Zetec|Zetec]] designs.

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