A prototype racing car, the Nissan R391 was manufactured by Nissan and their motorsports equivalent Nismo for 1999 24 Hours of Le Mans event. The R391 in fact replaced the Nissan R390 GT1.
In 1995, Nissan returned to sports car racing and the motorsports division Nismo entered the Le Mans prototype class with the renowned Skyline GT-R LMs. However, in 1997, Nismo came up with more advanced R390 GT1 which was essentially a prototype as well as street-car
When rules were revised in 1999 for GT, many major automakers found it difficult to manufacture homologated vehicles similar to the prototypes than the original GT cars. As a result, all the major automakers including Mercedes-Benz, Toyota, Panoz, BMW, and Audi shifted to the prototype class with an option of open cockpit prototypes or closed cockpit vehicles which were progressed from the previous GT class. Nissan on the other hand, decided not to go with evolved car rather they opted to build an independent vehicle with open cockpit.
Nissan assigned the duty of designing and assembling the new E391 to the UK based firm G-Force Technologies. The responsibility of design was on Nigel Stroud, while the Glenn Elgood worked as race team manufacturer. Nissan also signed an agreement with the Courage Competition, long time customer of Nissan’s second hand racing cars. According to agreement, Nissan would provide their VRH35 3.5-L turbocharged V8 motors to Courage and in return would get the expertise from Courage for their new R391. Purchasing a Courage C52 chassis was also a part of agreement
In R391, Nissan opted for a new version VH engine and dropped the idea of using the turbocharging as in case of former VRH35L. The Nissan directed its team to use a modified naturally aspirated version of the VRH engine designated as VRH50A. This larger 5.0-L engine nullified the loss of turbocharger, yet retained the strength of VRH35L engine.
In 1999 event of 24 Hours of Le Mans, Nissan decided to enter with their two new R391s and a Courage C52 featuring an older VRH35L motor. In May, the official testing for Le Mans was held where both R391s were able to set fastest time for 10th and 13th place beating many of the entries from Mercedes-Benz, Audi and BMW, but failed to beat Panoz or Toyota.
In an actual race, Nissan once again showed some class by finishing 12th. However, the other R391 that was driven by Eric van de Poele, crashed during the first qualifying round as a result of which car sustained irreparable damage and Eric van de Poele also got his vertebra broken. So, the Nissan raced in the event with a single R391.
The only R391 in the event showed its class by climbing up to the 4th place before an electrical problem in the engine forced the car to quit the race after completing just 110 laps. However, the Courage C50 managed to survive throughout the race and finish an overall 8th place. Interestingly, the Courage Competition’s own entry with the similar Nissan turbo V8 finished an overall 6th, i.e. eight laps ahead of Nissan Courage C52.
The R391 took part in another event later same year at the invitational ‘Fuji 1000 km’ backed by the le Mans ruling body, ACO (Automobile Club de l’Ouest). The winners of the race were supposed to get automatic entries to the next year’s 24 Hours of Le Mans.