The FW11 had been introduced in 1986, when it also won nine races across the season. That year ended in painful fashion for Williams: Mansell suffered a dramatic tyre blowout in the final race in Australia while needing only third place to win the title, and Piquet also fell just short of Prost's McLaren in the championship standings. Williams nonetheless won the Constructors' title. The FW11B was a refined evolution for 1987, designed by Frank Dernie, retaining the Honda 1.5-litre turbocharged V6 engine that had powered both cars.
Piquet secured the Drivers' Championship despite winning fewer races than Mansell across the season. His title challenge was assisted by greater consistency — he finished in the points in every round except San Marino, Belgium, and Australia — and by the misfortune that befell his teammate. Mansell's campaign included six victories, among them a celebrated come-from-behind win at the British Grand Prix at Silverstone where he passed Piquet for the lead with three laps remaining. His championship hopes were ended when he suffered a heavy crash during practice for the Japanese Grand Prix.
Ayrton Senna in the Lotus, which Honda also supplied with an engine — albeit the previous year's RA166E rather than the current RA167E used by Williams — mounted a consistent challenge, but the FW11B's overall superiority was decisive.
The FW11B served as a development platform for one of the most significant technical projects in Williams history. The team, primarily through Piquet's involvement and chief designer Frank Dernie, developed and tested its own active suspension system during the season. Mansell had prior negative experience with a different iteration of active suspension on the Lotus 92 in 1983 and declined to participate in the development programme.
After initial difficulties with a hydraulic prototype tested on a 1984 FW09, Dernie redesigned the system and brought in engineers Paddy Lowe and Steve Wise to build an electronic computerised version. To avoid using the name held under copyright by Lotus, Williams called the technology Reactive Ride. At the Italian Grand Prix at Monza, Piquet debuted the system in competition, recording the highest speed of the 1987 season at 218.807 mph (352.135 km/h) — approximately 5 mph faster than Mansell could achieve with the passive-suspension version of the same car. Piquet won the race from Senna's Lotus, with Mansell third.
Plans during the season also included development of a semi-automatic transmission, though this did not reach implementation.
The FW11B proved to be the last Williams car to race with a Honda engine. During the Hungarian Grand Prix weekend, Piquet announced his move to Lotus for 1988, where he would again partner with Honda. Honda subsequently confirmed that they too were switching from Williams to McLaren from 1988 onward, despite having a year remaining on their contract with the team.
The reasons cited centred on the team's refusal to enforce number-one status for Piquet in races against Mansell. Honda and Piquet believed this cost Piquet the 1986 Drivers' Championship. Williams also declined Honda's reported preference that Mansell be dropped in favour of Japanese driver Satoru Nakajima, who instead made his debut with Lotus in 1987. Frank Williams retained Mansell as a proven race winner with championship-contending ability, a decision supported by results.
The FW11B was the last Williams car with a turbocharged engine until the FW36 in 2014.
Across two seasons, the FW11 and FW11B combined for 18 victories, 16 pole positions, and 278 championship points, making the family of cars one of the most successful Williams designs of any era. The development of the Reactive Ride system on the FW11B laid groundwork that would continue to evolve into Williams' active suspension programme of the early 1990s. In the sim racing space, Mansell's FW11 appeared in Gran Turismo 3 and Formula One 05, while Piquet's FW11B was included in Toca Race Driver 3.