The apparatus of the present invention is intended to provide improved fuel economy for vehicles. Large internal combustion engines have not been constructed with a view of optimum fuel economy. It is particular adapted for attachment to an older engine. Internal combustion engines of the sort constructed with a multi-barrel carburator opening into an intake manifold are of particular interest. In the ordinary internal combustion engine, the cylinders are arranged in banks of four each. An intake manifold sits centered on top of the engine. The intake manifold is a conduit extending to the intake valves of the several cylinders. It is a device adapted to deliver combustible air and fuel mixture to the cylinders flowing under vacuum pull as a result of the recirocating motion of the cylinders. The passages enable flow to one cylinder to be interrupted when that valve closes and the flow diverted to another cylinder. This is advantageous.
A central cavity or chamber in the intake manifold is constructed. This cavity or chamber communicates with branches which extend to the individual cylinder intake valves. In the customary construction of such an engine, a carburator is attached to the top side of the manifold. Carburators customarily have either two or four barrels, which are individual carburator mechanisms duplicated to attain better mixing and more even distribution. Each barrel incorporates a downwardly directed venturi communicated at the upper end with a common air cleaner and having carburator jets therein. Small and middle sized engines normally have two barrels while larger engines are typically constructed with four barrel carburators. The apparatus of the present invention is adapted to be an add-on device for pre-existing engines having a multi-barrel carburator communicated with an intake manifold. The apparatus of the present invention is particularly easy to install. Customarily, a carburator is bolted to the top side of the manifold by bolts which extend thereabove. The carburator is equipped with a flange plate having four bolt holes arranged at the corners. The present invention is inserted between the carburator and the manifold with gaskets above and below. It includes air inlet tubes positioned well below the opening of the manifold so that air is injected directly into the manifold passages.