IMSA-GTP series

Nissan Grand Prix in Mid-Ohio 1991. In the lead Tommy Kendall in front of Wayne Taylor (both on an Intrepid RM-1), followed by Davy Jones (Jaguar XJR-16), Chip Robinson and Geoff Brabham (Nissan NPT-91) as well Raul Boesel (Jaguar XJR-16) and James Weaver (Porsche 962)

The IMSA-GTP series was a sports car racing series that ran from 1981 to 1993 under the auspices of the International Motor Sports Association in the United States and Canada .

The IMSA GT racing series had existed since 1971 when IMSA founder John Bishop started a racing series for GT vehicles. With the introduction of Group C in 1981, the IMSA also opened up to these racing prototypes . While GT vehicles continued to be driven at the same time, from 1981 onwards, in addition to special constructions that were built exclusively for the GTP class, racing cars such as the Porsche 956 and the Porsche 962 were also used. The GTP vehicles complied with the technical regulations of Group C with the not insignificant difference that there were no fuel restrictions in the IMSA GTP series. In contrast to the races in the World Sports Car Championship , the teams could use as much gasoline as they wanted.

Endurance races such as the 24-hour race at Daytona and the 12-hour race at Sebring , which were part of the racing series during the GTP era, as well as sprint races on street circuits and 200-mile races on permanent racetracks were driven.

The first overall winner in 1981 was the Briton Brian Redman , who drove a Lola T600 with a Chevrolet engine. With the introduction of the Porsche 962 in the race series a three-year hegemony of began Porsche in 1988 of Nissan was terminated. With the entry of Jaguar , Toyota and Mazda , the series reached its peak in the second half of the 1980s. The series attracted a large number of top drivers, which was mainly due to the high prize money that was paid out at each race. The series was also very popular with the spectators, in some cases the starting fields were twice as large as in the Group C championship.

In 1985, the Camel Light class was introduced in addition to the GTP and GT cars to open up the series to 2-liter prototypes as well.

In the early 1990s, the series went into crisis for several reasons. In 1992, Porsche withdrew and concentrated on the Indianapolis project in the USA . As a result, the Japanese manufacturers dominated, which in turn forced many private teams to give up, who could not afford the expensive prototypes from Asia and whose Porsche 962s were inferior. With the withdrawal of Mazda and Toyota in 1992, the end was predetermined. When in 1993 the audience - who were also interested in the series because of the great variety of brands - turned away and thus jumped off important sponsors, the last race of the series was held on October 2, 1993 in Phoenix.

Overall winner 1981–1993

year	class	vehicle	driver
1981	GTP class	Lola T600	Brian Redman
1982	GTP class	Porsche 935 Turbo	John Paul Junior
1983	GTP class	March 83G	Al Holbert
1984	GTP class	March 83G	Randy Lanier
1985	GTP class	Porsche 962	Al Holbert
	Lights class	Mazda Argo	Jim Downing
1986	GTP class	Porsche 962	Al Holbert
	Lights class	Mazda Argo	Jim Downing
1987	GTP class	Porsche 962	Chip Robinson
	Lights class	Mazda Argo	Jim Downing
1988	GTP class	Nissan GTP ZX Turbo	Geoff Brabham
	Lights class	Buick Tiga	Tom Hessert
1989	GTP class	Nissan GTP ZX Turbo	Geoff Brabham
	Lights class	Buick Spice	Scott Schubot
1990	GTP class	Nissan GTP ZX Turbo	Geoff Brabham
	Lights class	Buick Spice	Tomas Lopez
1991	GTP class	Nissan NPT-91	Geoff Brabham
	Lights class	Acura Spice	Parker Johnstone
1992	GTP class	Toyota Eagle MKIII	Juan Manuel Fangio II
	Lights class	Acura Spice	Parker Johnstone
1993	GTP class	Toyota Eagle MKIII	Juan Manuel Fangio II
	Lights class	Acura Spice	Parker Johnstone

literature

• JA Martin and Ken Welles: Prototypes - the History of the IMSA GTP Series . Bull Publishing, Phoenix 2000, ISBN 1-893618-01-3 .