Fuel Injector Insert

CIS-E Fuel Injector Insert:

The Fuel Injector Insert is located in the intake manifold runner, it is positioned between the fuel injector and the the intake manifold. The Fuel Injector Insert consists of an upper and lower section, the upper section is made of brass the lower section, (also called the air shroud) is made of a high temperature plastic. Two small O-rings are used to seal the injector insert to the intake and a larger thicker O-ring is used to seal the fuel injector to the insert. The upper brass section of the injector insert has threads holding it in the intake manifold, an internal 12mm hex at the top of the insert is used remove and install it. The fuel injector is held in place by the large O-ring fitted to it. The function of the injector insert is to; mount and seal the fuel injector, isolate the fuel injector from engine heat and vibration, create an air flow through the air shroud to better atomize the fuel as it leaves the injector tip.

At idle, lower manifold pressure at the injector tip induces an air flow through the injector insert air shroud. The air flow then surrounds the injected fuel stream as it leaves the injector tip. The air needed for this comes from a small air passage made in the intake manifold to the injector inserts, a vacuum routes air from upstream of the throttle valve to the air passage. The advantages of air shrouding the fuel injector is, lower fuel consumption, reduced exhaust emissions and smoother idle due to improved atomization of the fuel