Group R consists of six classes, designated R1, R2, R3, R4, R5 and R-GT; some of these groups contain their own sub-groups, with cars allocated to each group based on their weight, engine size and powertrain. The first batch of rules, which were introduced in 2008, featured the R1, R2 and R3 classes. These were restricted to two-wheel drive cars with atmospheric engines up to 2000cc. Supercharged engines were allowed only in R3T (petrol) and R3D (diesel) sub-classes. Since 2015 the R1, R2 and R3 classes allow supercharged engines with a 1.5 equivalency factor for displacement. Additional regulations were issued in 2011 which covered the R4 and R-GT classes; the R4 was conceived as an evolutionary step for previously-homologated Group N4 cars, turbocharged, all-wheel drive cars based on production models. The R4 class is for cars competing under
Group N regulations for production cars prior to
2013. No new models would be homologated under R4 regulations, with the FIA taking the long-term view that these would be replaced by bespoke kit cars. The R4 Kit cars have a standard engine, four-wheel drive powertrain and suspension. In January 2017, French racecar manufacturer
Oreca was selected as supplier. R-GT was introduced to allow
Grand Touring cars that competed in
sports car racing to enter rallies. The R5 class was designed to replace
Super 2000 cars, and its regulations were introduced in 2013. Prior to 2014, there was no specific championship for cars entered under R-GT regulations, and R-GT cars were ineligible to score points in any existing championship outside the
World Rally Championship. The FIA R-GT Cup for R-GT cars started in 2015, sharing some events from the
WRC and
ERC events. The World Rally Championship has historically had specific support championships that each class has been eligible for. Cars classified as R1, R2 and R3 contested the
WRC3 Championship for two-wheel drive cars between 2013 and 2018; specially-prepared R3T, later R2B cars, were also used in the
Junior WRC. Cars classified as R5 compete in
WRC2; and WRC3 in 2020 and 2021, whilst regional championships may allow R5 alongside existing
Super 2000 and
Group N Production Cars. Cars classified as R-GT competed in the
R-GT Cup until it ceased at the end of the 2022 competition.
Summary ==Models==