For 1991, Nissan officially withdrew from the World Sportscar Championship. However Nismo planned to continue competition in the All Japan Sports Prototype Championship, and decided to upgrade the R90CPs to better compete with Toyota and Mazda. The new cars, known as R91CP and R91VP, would have slight modifications over the previous car. Most notably, the boxy turbo inlets which had been placed on the rear fenders of the R90CP were made into smaller slits, while a large snorkel was added to the top of the engine cover to cool the rear brakes, in place of the previous twin brake ducts. The cars would be further modified for 1992 with an upgraded VRH35Z twin-turbo V8, while the cars were renamed R92CP.