The 2J competed in the Can-Am series and qualified at least two seconds quicker than the next fastest car, but mechanical problems limited its success. It only ran in the 1970 season, after which it was outlawed by the Sports Car Club of America (SCCA). Although originally approved by the SCCA, they succumbed to pressure from other teams who argued that the fans constituted "movable aerodynamic devices". Sanctioning body FIA had banned such devices beginning with the 2E. There were also complaints of debris generated by the fans damaging the following cars. McLaren argued that if the 2J were not outlawed, the Can-Am series would be ruined by its dominance – something McLaren had been doing since 1967. A similar fan was used in Formula One eight years later on the Brabham BT46B, which won the 1978 Swedish Grand Prix, but the company reverted to the fanless BT46 soon afterward due to concern for a rules violation. The car was later deemed to have been within FIA technical specifications.