 Complete the following phrase:  Brabham began the 1982 season with two BMW-powered BT50 chassis at the South African Grand Prix, where Piquet and Patrese qualified second and fourth respectively, but retired early in the race. Team principal Bernie Ecclestone was under pressure from the teams title sponsor, Parmalat, to defend Piquets championship, and opted to race with the Cosworth-powered BT49 chassis at the Brazilian Grand Prix, which Piquet won but was later disqualified for circumventing the minimum weight limit by running water-cooled brakes. Both drivers also raced the BT49 at the Long Beach Grand Prix, and the team boycotted the San Marino Grand Prix as part of the ongoing FISAFOCA war. For the following race, the Belgian Grand Prix, Piquet and Patrese switched back to the BT50, but Piquet finished three laps behind the winner and Patrese retired. As the relationship between Brabham, BMW and Parmalat became strained, Ecclestone was forced to compromise, with Piquet continuing development of the BT50 whilst Patrese raced with the Cosworth chassis. At the Monaco Grand Prix, Patrese won, whilst Piquet was more than two seconds slower in qualifying and retired from the race. The nadir of BMWs Formula One involvement thus far came at the 