An expandable manifold comprises an expansion chamber defined by a resilient surface. Intake is provided by a conduit extending into the chamber. As reverse impulses resulting from the closing of an intake valve enter the expansion chamber from the output end of the chamber, the volume of the chamber increases as the resilient surface expands. The reverse impulses propagate along the inner surface of the resilient surface toward a void defined by the outer surface of the conduct and the inner surface of the resilient surface. When the intake valve reopens, the reverse impulse flow is redirected and combined with intake flow from the source of fuel/air. The reverse impulses are redirected within and proximate the void. Energy associated with the reverse flow is redirected and combined with the forward flow to improve overall engine performance.