How Does a Throttle Body Spacer Work?

A throttle body spacer is a component added to the throttle body of a fuel injection engine to improve fuel efficiency and add power to the engine. The throttle body has a similar function to the carburetor on a non-fuel injection engine. A carburetor, however, controls the mix of air and fuel that is sent into the engine's cylinders, while a throttle body only regulates the air flow to the engine, in cooperation with the fuel injection system.

The throttle body of a fuel injection engine regulates the amount of air that goes into the engine and is subject to the driver's control. It is placed between the air filter and the car's intake manifold. The throttle body consists mostly of a throttle plate, a butterfly valve that controls the airflow.

In a fuel injection engine, the accelerator connects to the throttle by a throttle cable. This cable causes throttle linkages to open the throttle plate, which adds more airflow to the engine. The increased airflow requires an increase in fuel, in order to maintain the correct mixture of fuel and air for the engine. The engine control unit is signaled to increase the fuel provided to the fuel injectors, in order to ensure that the ratio remains correct. The increased fuel and air mixture adds to the engine's power by creating a larger explosion in the engine.

A throttle body spacer creates a larger area around the throttle body. This gives the throttle body a larger capacity for air intake, when the accelerator is pressed. When the throttle body valve opens, the throttle body spacer allows a greater amount of air to pass through the valve, increasing the power available to the car. This also improves the car's energy efficiency, due to the fact that the air is readily available, so the car does not need to expend effort to bring it to the throttle plate.