Throttle body spacer how does it work

When the intake valve of the cylinder head opens, air is being sucked into the engine, so air in the intake runner is drawn in rapidly toward the cylinder. When the intake valve closes suddenly, this air slams to a stop and stacks up on itself, forming an area of high pressure. This high-pressure wave makes its way up the intake runner away from the cylinder.

When it reaches the end of the intake runner, where the runner connects to the intake manifold, the pressure wave bounces back down the intake runner. However, if the runner is exactly the right length, that pressure wave will arrive back at the intake valve just as it opens for the next cycle.

This extra pressure helps cram more air-fuel mix into the cylinder — effectively acting like a turbocharger. The problem with this technique is that it only provides a benefit in a fairly narrow speed range. The pressure wave travels at the speed of sound which depends on the density of the air down the intake runner.

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. Vee Enne is a U. Military Veteran who has been writing professionally since We'll see. Air flowing into an engine doesn't just flow straight through in one big mass. When air flows along a surface, some of the air "sticks" to the surface, forming a very slow-moving boundary layer that acts as a sort of "lubricant" for air flowing over it.

When air goes through your throttle body, a boundary layer of stagnant air forms on the inside of the throttle body bore and on the front of the throttle blade. Air flowing over this boundary layer goes into the intake manifold, where it sits in a central chamber -- the plenum -- waiting to be sucked into one of the intake runners.

Here's a bold statement, backed up by about four centuries worth of physics: Any manufacturer that claims its spacer induces a helpful straightening or swirling of the air is -- wait for it -- lying. The boundary layer that builds up on the throttle body walls is thick enough to cover those machined swirls in the spacer bores. This is true even of spacers that use very thick, helical grooves, because the boundary layer will simply fill them like cement and the air will skip over them.

So, the best-case scenario is that the airflow completely ignores the helical groove. The worst is that the groove makes the boundary layer even thicker, restricting flow. But that slight disruption in airflow will do one thing, at least: It'll produce a constant whistling or roar to remind you that you installed a throttle body spacer.

In the modern multi-point fuel injected engine, fuel enters into the airstream just ahead of the cylinder head, at the end of the intake runner. So, let's say, hypothetically, that you do have a vortex of air swirling in the plenum. When an individual cylinder's intake valve opens, it's going to pull a massive chug of air from the vortex.