The R91CP was produced by updating the existing R90CP chassis rather than designing an entirely new car. The most visible aerodynamic changes addressed the R90CP's rear bodywork: the large boxy turbo inlet scoops mounted on the rear fenders were replaced with smaller slitted intakes, and a substantial snorkel was added to the top of the engine cover to provide cooling for the rear brakes, replacing the previous twin-duct arrangement. These modifications were developed with assistance from the Yatabe wind tunnel at the Japan Automobile Research Institute. The core mechanicals — the Lola-derived T90/10 chassis architecture and the VRH35Z twin-turbo V8 — were carried over from the R90CP. For 1992, the cars received an upgraded version of the VRH35Z and were renamed R92CP.
The factory team retained its driver lineup from 1990: Masahiro Hasemi, Toshio Suzuki, Kazuyoshi Hoshino, and Anders Olofsson. Private entrants also operated modified R90C variants alongside the factory effort — Nova Engineering ran its R91CK (built around an upgraded customer chassis) and Team Le Mans competed with the R91VP, a modified R90CP.
The R91CP was dominant in the opening rounds of the 1991 JSPC. The factory team won the opening race at Fuji outright, with the Nova Engineering R91CK finishing second. When Toyota introduced its new 91C-V, the R91CPs initially absorbed the challenge without difficulty, taking the top two positions a lap ahead of the new Toyota at the second Fuji round.
Competition tightened as the season progressed. Toyota improved its 91C-V sufficiently to win the third Fuji round, with Nissan finishing second. The 1000 km Suzuka produced a reversal of the factory team's fortunes, with the Nova Engineering entry finishing ahead of the works cars. Through the balance of the season the two Japanese manufacturers traded victories, but Nissan's cumulative points advantage proved sufficient. The factory team took Nissan to the manufacturers' championship by three points over Toyota. Kazuyoshi Hoshino and Toshio Suzuki claimed the drivers' championship by just two points over Toyota's leading pair, in one of the closest title finishes in JSPC history.
The R91CP achieved its most prominent international result at the 1992 24 Hours of Daytona, where the factory Nismo team entered a single car in the invitational class for Group C prototypes alongside modified R90CKs from NPTI and the Nova Engineering R91CK. While the modified R90CKs struggled in the IMSA GTP class, the R91CP proved far superior, winning the invitational class by nine laps.
Nismo developed the R91CPs into the R92CP specification for the final season of the All Japan Sports Prototype Championship in 1992, featuring a further upgraded VRH35Z engine. The championship was split into two classes — C1 for the older-formula cars including the R92CPs, and C for new 3.5-litre normally aspirated machinery meeting the 1992 World Sportscar Championship rules. In the C1 class, Nissan dominated once again, winning the class manufacturers' title despite Toyota's TS010 proving untouchable in the upper C class. Kazuyoshi Hoshino won the individual C1 drivers' championship.
The R90C platform made its final competitive appearance at the 1993 1000 km Suzuka, the opening round of the new All Japan Grand Touring Car Championship. Team Le Mans entered a former factory R92CP and Nova Engineering entered its R91CK; the two cars finished first and second overall, ahead of the only other prototype entrant.
The R91CP and its successors demonstrated that the R90C platform possessed remarkable longevity. What began as the 1990 European Lola-chassis Group C contender was refined by Nismo into a car capable of winning championships through 1992. The programme produced three consecutive JSPC manufacturers' titles and helped develop both Kazuyoshi Hoshino and Toshio Suzuki into multiple Japanese championship winners. The VRH35Z engine at the heart of the programme was one of the most successful twin-turbo V8s in Japanese motorsport history.