BMW first made a deal to supply the M12/13 engine only to the Brabham. Testing of the M12/13 started in late 1980. A new car, Brabham BT50 was design for the engine. The new car was not finished until will into the season. The team's lead driver, Nelson Piquet, tested the BT50 throughout 1981. The car was unreliable until Bosch improved the electronics.