Ahead of this weekend’s 24 hours of daytona, the international motor sports association (IMSA) announced the comeback of the named IMSA GTP. This is reminiscent of the great era of sports car racing in the 1980s.
Nissan won the IMSA GTP four times. 1990 and 1991 the nissan NPT-90 came into use. (photo: webster – archive fabian P. Wiedl)
Endurance fans are certain, sports car racing is on the brink of great times. Because the new version of the rulebook is just attracting numerous manufacturers to the long haul. With porsche (19), audi (13 victories), ferrari (10 victories), peugeot (2 victories) and BMW (1 victory), brands are returning to the sports cars that have so far claimed 45 victories at the 24 hours of le mans. Only ford, mercedes-benz and jaguar are still missing. Returning racers can choose to compete in a le Mans hypercars (LMH) or a le Mans daytona hybrid/hypercar racer (lmdh).
In addition to pure racing technology, the LMH also provides for race cars derived from production models. The lmdh, on the other hand, are based on buyable LMP2 race cars. As with the daytona prototype dpi, the manufacturers will equip them with their own engine and adapt the bodywork to the look of the brand. Despite these completely different concepts, both classes are expected to be equally fast on the track. Because the wish is that at the 24 hour races in le mans or in daytona race cars of both vehicle classes fight for the overall victory. If this is successful, it will not matter which class of car a manufacturer ultimately chooses to enter.
"when the flag drops, the bullshit stops!"
Experience shows that when the races are exciting, the public flocks to the tracks or huddles in front of the TV screens. Two different classes are disturbing there under circumstances.
The International Motor Sports Association (IMSA) therefore announced this weekend that both classes of car will be raced under the umbrella term IMSA GTP from the beginning of 2023. This also marks the return of a name steeped in tradition. Finally, from 1982 to 1993, IMSA sports prototypes competed under the name IMSA GTP.
At that time, there were race cars in north america that were technically reminiscent of their "colleagues" from group C. But there were three major differences. FISA, the world governing body for automobile sport, limited the fuel consumption in its regulations. This was politically expedient in europe at the time, as it gave motorsport a green coat of paint.
IMSA GTP winner from 1982 to 1993:
- 1982: john paul jr. – lola T600 cosworth (three rounds) and porsche 935 JLP-3 (15 rounds)
- 1983: al holbert – march 83G
- 1984: randy lanier – march 83G
- 1985: al holbert – porsche 962
- 1986: al holbert – porsche 962
- 1987: chip robinson – porsche 962
- 1988: geoff brabham – nissan GTP ZX-turbo
- 1989: geoff brabham – nissan GTP ZX-turbo
- 1990: geoff brabham – nissan GTP ZX-turbo / nissan NPT-90
- 1991: geoff brabham – nissan NPT-91
- 1992: juan manuel fangio II- toyota eagle MKIII
In addition, the limit – over the distance of the race – put some brakes on the race cars for the sake of safety on the track. But these rules favored the rather smaller European racing engines. Traditionally, large-volume V8 engines dominated american motorsport. IMSA knew that the fuel consumption of the V8s was higher than that of their European counterparts. For this reason, the Americans dispensed with the restrictive fuel consumption regulations of Group C in their GTP regulations.
Of all things, the most successful Group C bolide of the first years of the new Group C regulations could not be entered in America. The 956 did not meet IMSA GTP safety regulations. (photo: archive autonatives.De)
In order to limit performance, it stipulated that GTP engines had to be derived from production engines. This ruled out the use of pure racing technology along the lines of the ford cosworth, which was also used in group C, in north america. For safety reasons, the driver’s feet also had to be behind the front axle in the american racing cars. This prevented the best race car of the early group C years, the porsche 956, from making it to america.
IMSA integrated the prototypes into IMSA GT championship!
With the GTP class, IMSA added a new top class to its existing "IMSA GT Championship. Whereby the name GTP was not new. Because was already used in 1976 for prototypes jointly defined by IMSA and le man’s organizer ACO. IMSA was founded on the initiative of john bishop, who had been an official in the SCCA since the 1950s. Bishop was involved in the organization of the US grand prix from 1962 and participated in the foundation of transam and canam. in 1969, bishop resigned from all SCCA offices in order, with the support of NASCAR chief bill france sr. To create the IMSA.
Jean Rondeau built his first race car with money from a wallpaper manufacturer. It was created according to the GTP regulations, which were jointly drafted by the ACO and IMSA. (photo: tom schwede)
IMSA held its first races in the formula vau and formula ford classes. From 1971, the IMSA organized its own championship, the "IMSA GT Championship. "GT" stood for "grand touring". Cars were admitted that complied with the rules of groups 2 and 4 of the official FISA regulations. At the IMSA they raced in four classes:
- GTO for group 4 cars with more than 2.5 liters displacement.
- GTU for group 4 vehicles with a displacement of less than 2.5 liters.
- TO for group 2 touring cars with more than 2.5 liters of displacement.
- TU for group 2 touring cars with a displacement of less than 2.5 liters.
The letters "O" and "U" stood for "over" and "under" 2.5 liters of displacement. From 1972, the cigarette brand camel was the main sponsor of the series. One year later, IMSA took over the organization of the 12 Hours of Sebring, which was included in the calendar of the "IMSA GT Championship". This created a racing calendar with an exciting alternation between long-distance races (24, 12 or 6 hours) and sprint races (100, 150 or 200 miles). 1 hour)
1974 bishop bought the transam series. So it was obvious to let the touring cars race there now. In the GT championship, IMSA dispensed with the touring car classes. At about the same time, John Bishop began to have regular exchanges with the officials of the Le Mans organizers, the ACO. The "grand touring prototypes" (GTP) regulations were created in the process.
At the GTP premiere in 1976, a Lancia Stratros also competed in this class at the 24 hours of Le Mans. Christine dacremont and lella lombardi shared the cockpit. The women’s team finished in 20th place. (photo: archive autonatives.De)
In 1976, inaltera (rondeau) and welter brought the first GTP to le mans. A Lancia Stratos, which was not homologated in any other FISA group at the time, also raced in le Mans as a GTP. At the same time, NASCAR sent two race cars to France. In turn, bishop invited the inaltera LM to the 24 hours of daytona the following year. It remained a one-time guest appearance. Nevertheless, the fuse was now lit. In the years to come, race cars in the GTP class regularly raced at Le Mans.
In the USA, Group 5 was called IMSA GTX!
As early as 1977, not all classes competed in all IMSA races. At the hallett motor racing circuit, for example, only the race cars of the small GTU raced. At other events, there were separate races for GTO and GTU, which differed in distance. This was IMSA’s response to the increasing performance of the big class. This also ensured that IMSA offered fans at the track a colorful and exciting day of racing. The spectators honored this and flocked to the track in droves. It also helped when IMSA added another car class to its championship a year later. The regulations for the new GTX class were based on Group 5, which FISA had been running since 1976.
IMSA was pragmatic. Even after the prototypes were approved, it simply allowed the previously GTX-named Group 5 cars to continue racing. They competed together with the GTP in one classification group. Especially the porsche 935, like the porsche used by john fitzpatrick, were still part of the scene for years to come. (photo: webster – archive fabian P. Wiedl)
FISA decided to simplify its class structure. The new regulation came into force in january 1982. FISA based the definition of its new prototype class, Group C, on the IMSA and ACO GTP class. The U.S. rejected FISA’s supplemental fuel rules. The ACO also hesitated, but FISA president jean-marie balestre put pressure on his compatriots. Because Balestre was also the head of the French national association. The latter threatened not to advertise the ACO race internationally. The threat was effective, the ACO relented and accepted the gasoline rules.
Group C and IMSA GTP – two sides of the same coin!
With the IMSA GTP, the IMSA replaced the GTX cars from 1982 onwards. Whereas unlike in europe they could simply continue to be used. Especially the porsche 935 still belong for years to the inventory also in the GTP. At this point, IMSA also ignored the FISA requirement that a prototype must be exactly one meter high. Ford therefore sent the team zakspeed USA with the ford mustang turbo into the IMSA GTP series. This race car was essentially a super capri from group 5, which had previously been a DRM racer.
For the GTO and GTU, everything stayed the same. Here, too, the rules were moving further and further away from the FISA rules. The safety regulations regarding the position of the driver’s feet in the IMSA GTP prevented the best prototype of the early Group C from competing in North America. because in the porsche 956 the drivers’ feet protruded over the front axle. Without the sports car from zuffenhausen, the first IMSA GTP title went to john paul jr., who actually used the now equally legendary porsche 935 JLP-3 in the GTP class. To save the prototypes, it should be mentioned that paul jr. With still three with the prototype lola T600 chevrolet competed.
In the following two years, al holbert and randy lanier, both driving a march 83G, secured the IMSA GTP title. In retrospect, it does not cast the best light on the IMSA series that with paul jr. And lanier two of the first three title winners financed motorsports with drug deals. porsche introduced the type 962 in 1985. In the successor to the 956, the pedals are located behind the front axle. The new porsche was also immediately the measure of things in IMSA. Al holbert (two) and chip robinson brought three IMSA titles in a row to zuffenhausen.
In 1991, the Jaguar XJR-16 competed in the IMSA GTP. With four victories, the cat was the most successful car of that year. Nevertheless the title went once again to nissan. (photo: webster – archive fabian P. Wiedl)
In 1988, the Japanese carmakers began to dominate the IMSA. Geoff brabham drove to four straight titles for nissan. In the early years, the australian drove the nissan GTP ZX-turbo with a chassis from lola. From 1990 onwards, jack brabham’s son switched to the nissan NPT-90, which nissan built itself in the USA. for marketing reasons, this prototype was also initially called GTP ZX-turbo in the racing lists. The NPT-91 evolutionary stage was the first to be given an official name. In 1992 and 1993, Juan Manuel Fangio II won the IMSA GTP title. juan manuel fangio’s nephew competed in the toyota eagle MKIII. This race car came from the all american racers team of racing legend dan guerney.
The great days of the IMSA GTP were over by the end of 1993!
Until the early 1990s, the IMSA GTP was surprisingly stable. In addition to nissan and toyota, jaguar also had a factory program. Numerous private teams drove porsche. With a second prototype class called "IMSA lights", america followed the example of FISA from 1985 onwards and also offered ambitious amateurs the opportunity to race in front of large audiences. Whereas the IMSA knew how to bring the race to the fans like no other series. The races in the streets of columbus (ohio from 1985-88), del mar (california 1987-92) or miami (1983-93) are legendary today.
But in the end everything went very fast. Neither ford nor chevrolet managed to drive to the top with their prototypes. This was also due to the fact that they tried for a long time to compete with cars that were reminiscent of production vehicles. As long as the "foreigners" provided the excitement, the series worked. But at the end of 1992 nissan and jaguar withdrew. At the top, toyota was now "fighting" against the private joest team, which was almost using an oldtimer in the form of the porsche 962. No wonder toyota won ten of the eleven races of the season. IMSA reacted and elevated the World Sports Car (WSC) to the new top class in 1994. The name IMSA GTP disappeared from the racing calendar for the time being. The traditional name will return in early 2023.
Info on the cover picture of this article:
nissan won the IMSA GTP four times. In 1990 and 1991 the nissan NPT-90 was used.
Photo: archive fabian P. Wiedl