Also known as the “Special Production Cars” class from 1976 to 1982, Group 5 was in fact a sort of prototype class but based on road cars; it demanded only that the car was previously homologated in Group 1 through 4 and that it retained the hood, doors, and roof of the homologated model. As such, most Group 5 cars were often of full spaceframe construction with the required body parts simply bolted on. It gave birth to a myriad of very large widebodied versions sporting wild aerodynamic enhancements.
In 1982, the class was replaced by Group B, which brought the same wild liberties to the world of rallying. While official FISA Group 5 competition stopped, it did continue to go on for a few years in Japan with the Fuji Super Silhouette series and in the USA’s IMSA GTX series. It is not quite clear why FISA Group B circuit racing did not really take off. The main reason is most likely that the new Group C regulations did not demand any kind of road car homologation and was a pure unrestricted prototype class. As such, Group C created too much of a blur between the old Group 5 & 6, making this type of racing shift towards pure prototypes while road car homologation-based racing shifted towards the cheaper to run Group A touring series.
Near the end of Group B (1986), there was a hint that Group B circuit racing might take off after all with the production of the Ferrari 288 GTO Evoluzione (which was the basis for the iconic F40) and the Porsche 959 (which gave birth to the 961 racing derivative). The latter pair is credited in reviving the “supercar” game which might have set the new standard for Group B circuit racing.
The FISA had also planned to introduce a new class called “Group S“, due to debut in 1988 with similar regulations as Group B, but required an homologation run of only 10 cars (instead of 200 for Group B). Basically a prototype class on its own, Group S was to favor testing of new and exotic materials and electronics (which were just starting to appear in motorsports). The new class might have attracted more manufacturers and help revive silhouette circuit racing. As history would unfold, Group B was banished at the end of 1986, as was the Group S idea to replace it, thus killing any and all FISA-sanctioned racing ambitions for these kind of cars.
Although Group 5 silhouette racing is a child of the mid-70’s, it is nonetheless a huge part of 80’s motorsport history that is fondly remembered by all racing fans of the time. It is worth to mention that the cars in Japan’s Fuji Super Silhouette series (1979~1984) are the basis for the bōsōzoku subculture (for the car segment) by their recreation of the wide body styles (sometimes even wider and exaggerated).
Here’s a few pictures of the awesome Group 5, Super Silhouette, and IMSA GTX race machines and their iconic super widebodies, low front air dams, and huge rear spoilers (strangely limited to normal body width);
Yet another argument for the statement that the 80’s was the golden era of pure motorsports… be it on dirt or on circuit!