Editing Supercars Championship (section)

===Group 3A===
[[File:Skaife-vp94.jpg|thumb|225px|[[Mark Skaife]]'s 1994 [[Holden Commodore (VP)|Holden VP Commodore]]]]
[[File:Lowndes-vr96.jpg|thumb|225px|[[Craig Lowndes]]' 1996 [[Holden Commodore (VR)|Holden VR Commodore]]]]

The concept of a formula centred around [[V8 engine|V8-engined]] [[Ford Australia|Fords]] and [[Holden]]s for the [[Australian Touring Car Championship]] had been established as early as mid-1991. With the new regulations set to come into effect in [[1993 Australian Touring Car Championship|1993]], Ford and Holden were both keen to know the details of the new formula by the end of 1991, putting pressure on the [[Motorsport Australia|Confederation of Australian Motor Sport]] (CAMS) to provide clarity on the matter. However, CAMS was waiting to see what the [[Fédération Internationale de l'Automobile|FIA]] did with its proposed international formula for 2.5- and 2.0-litre touring cars.<ref>Greenhalgh, Howard, Wilson (2011), p. 322</ref>

The new rules for the ATCC were announced in November 1991 and indicated that the V8 cars would be significantly faster than the smaller-engined cars. In 1992, CAMS looked at closing the performance gap between the classes, only to have protests from Ford and Holden, which did not want to see their cars beaten by the smaller cars. In June 1992, the class structure was confirmed:<ref name="50Y 323">Greenhalgh, Howard, Wilson (2011), p. 323</ref>

* Class A: Australian-produced 5.0-litre V8-engined Fords and Holdens
* Class B: 2.0-litre cars complying with [[Supertouring|FIA Class II Touring Car]] regulations
* Class C: normally aspirated two-wheel drive cars complying with 1992 CAMS Group 3A Touring Car regulations:<br />This class would only be eligible in 1993.<ref>CAMS Manual of Motor Sport (1993), p. 205</ref>

Both the [[Ford Falcon EB]] and [[Holden Commodore VP]] ran American-based engines, which were restricted to 7,500 [[Revolutions per minute|rpm]] and a [[compression ratio]] of 10:1. The Holden teams had the option of using the [[Group A]]-developed 5.0-litre [[Holden V8 engine]], although this was restricted to the second-tier privateer teams from 1994 onwards, forcing the major Holden runners to use the more expensive [[Chevrolet small-block engine|Chevrolet]] engine. The V8s were first eligible to compete in the endurance races of [[1992 Australian Touring Car season|1992]]. The distinctive aerodynamics package, consisting of large [[Diffuser (automotive)|front]] and [[spoiler (car)|rear spoilers]], was designed partly with this in mind, to give the new cars a better chance of beating the [[Nissan Skyline GT-R#Third generation (1989–1994)|Nissan Skyline GT-Rs]] in those races.<ref name="50Y 323" />

The new rules meant that cars such as the [[Turbocharger|turbocharged]] Nissan Skyline GT-R and [[Ford Sierra RS500 Cosworth]] were not eligible to compete in 1993, while cars such as the [[BMW M3#E30 generation (1986–1991)|BMW M3]] were. However, the M3 received few of the liberal concessions given to the new V8s and also had an extra {{convert|100|kg|lb}} added to its minimum weight, so<ref name="50Y 324">Greenhalgh, Howard, Wilson (2011), p. 324</ref> with the Class C cars eligible for 1993 only, the German manufacturer's attention switched to the 2.0-litre class for 1994.

Cars from all three classes would contest the [[1993 Australian Touring Car Championship]], as well as non-championship Australian touring car events such as the [[Bathurst 1000]]. However, for the purposes of race classification and points allocation, cars competed in two classes:
* Over 2,000 cc
* Under 2,000 cc

Originally, the 2.0-litre class cars competed in a separate race to the V8s. This was changed for the second round of 1993 after only nine entrants were in the 2.0-litre class for the first round at [[Amaroo Park]].<ref name="50Y 324" />

With the new regulations intended to be a [[Parity (sports)|parity]] formula, protests by the Holden teams indicated that the Fords had an aerodynamic advantage after they won the opening three rounds, beating the Commodores comprehensively. After round five at [[Winton Motor Raceway|Winton]], Holden was granted a new front and rear wing package. The BMWs were also allowed new splitters and full DTM-specification rear wings.<ref>Greenhalgh, Howard, Wilson (2011), p. 325–327</ref> Disparity between the Fords and Holdens continued to be a talking point during the next few years, with various concessions given to each manufacturer to try to equalise the two cars.<ref>Greenhalgh, Howard, Wilson (2011), p. 332–353</ref>

From [[1995 Australian Touring Car Championship|1995]], the 2.0-litre cars, now contesting their own series as [[Australian Super Touring Championship|super touring cars]], became ineligible for the Australian Touring Car Championship. They did not contest the endurance races at Sandown and Bathurst, leaving these open solely to the 5.0-litre Ford and Holden models.