an air compartment connecting one or more ducts with the heating or cooling unit; any enlarged section within an air duct with several duct, grille, or diffuser, connections
Located between the throttle body and the runners of an intake manifold, it is just like a chamber to distribute the intake charge and improve engine breathing.
A chamber, located between the throttle body and the runners of an intake manifold, used to distribute the intake charge evenly and to enhance engine breathing.