Ligier team manager, Gerard Ducarouge, said that the Ligier JS-11 had been in the planning stages for some time. The JS-9 had been tested as a "wing car" following the 1978 United States Grand Prix West, but the wind tunnel tests proved unsatisfactory. The JS-11 was built and tested in December 1978, with positive results. The V-8 engine was lighter and the Cosworth exhaust system was modified so that it sounded much the same as the old Matra engine's distinctive whine. The new body features of the JS-11 were revealed at the 1979 United States Grand Prix West.