Fuel injectors are available in various styles and designs. They can be divided in two specific categories: top feed and side feed. The designation of top feed and side feed indicates how and where the fuel enters the fuel injector.
Side Feed Fuel Injectors:
Side feed fuel injectors are injectors where the injector body is surrounded by fuel. The fuel is fed through a hole or holes in the side of the fuel injector. This category can again be sub divided into two groups: throttle body and manifold.