The Williams FW13 was a Formula One racing car used by the Williams team for the last 4 races of the 1989 Formula One season. An updated version, the FW13B, was used in the 1990 Formula One season.
The FW13 was designed by Argentine Enrique Scalabroni and featured the Renault RS1 and RS2 3.5 V10 engine. The car was driven by Belgian Thierry Boutsen and Italian Riccardo Patrese. Boutsen gave the car it's racing debut at the 1989 Portuguese Grand Prix and also its first win with a brilliant drive in very wet conditions at the 1989 Australian Grand Prix. The car was also late in arriving (race 13 of the 1989 season) due to the teams wish to get any bugs out in testing before its debut.
The FW13 was updated for the 1990 season and was dubbed the FW13B. The car featured revised sidepods and suspension upgrades. The FW13B proved fast and reliable for the Williams team. Both Patrese and Boutsen won a grand prix each in 1990 with Patrese winning at "home" in Imola and Boutsen winning in Hungary after also claiming pole position. Significantly, Patrese qualified 2nd, finished 4th and drove the fastest race lap in Hungary giving Williams plenty to celebrate that weekend.
The general feeling around the F1 paddock was that the FW13B of 1990 with its V10 Renault engine was the fastest car on the grid that year and that the only thing holding it back from challenging McLaren and Ferrari more often was Williams not having a true No.1 driver as both Boutsen and Patrese were seen by many only as journeymen second drivers who's former potential had gone largely unfulfilled. Many in the media felt that had Alain Prost signed with Williams and not Ferrari for 1990 then the McLaren-Honda's dominance might have been broken.
The FW13B was replaced for the 1991 season by the successful FW14.