Method of distributing air in an engine intake manifold

A method of distributing air to the combustion chambers of an internal combustion engine through a multi-plenum air intake manifold having an air intake and a pair of laterally spaced side plenums connected to one another by an acoustic balancing cross over passage and having a centralized plenum disposed between the side plenums operatively connected to the respective combustion chambers by short runners, said side plenums being connected to the combustion chamber by long runners, said short runners also being connected to the combustion chambers upstream and in series with said long runners comprising the steps of:

• a. closing said short runners so that intake air is routed to said combustion chambers through said side plenums and said long runners,
• b. blocking said acoustic balancing cross over passage for improving torque for a first range of engine speeds so that pressure waves in said side chambers constructively interfere in superposition to effect increased air flow through said long runners for increasing engine torque from idle to a mid speed range of said engine,
• c. subsequently opening said acoustically balancing crossover passage and said short runner valves so that air flow to said combustion chambers is primarily through said short runner valves that provide an increased flow capacity through said manifold to improve combustion in said combustion chambers so that said engine torque is further increased for a higher range of engine speeds.