What does the throttle body spacer do?

Many active devices can be used to increase the compressed air intake and boost your engine performance. However, that’s not something you should regularly expect from a passive device. It’s therefore incredible what just a piece of a metal ring like the throttle body spacer can do.

If you’ve never heard of it, no one can blame you, and you might be wondering – what does the throttle body spacer do? A throttle body spacer increases the airflow into the intake manifold by lengthening it and allowing a straight air supply to the intake. If you are not a car guy, we understand that this doesn’t sound clear at first, so this guide should provide a more detailed answer.

What’s a throttle body and what does it do?

Before we get to the significance of a throttle body spacer as an aftermarket modification to your vehicle, you must know about the throttle body itself. A throttle body is a crucial part of the vehicle’s air intake system.

It’s located between the intake manifold and the air filter, so it makes the center of the air intake system. Essentially, the throttle body determines the amount of air that reaches the combustion chambers of the car’s engine.

There’s a throttle body valve inside it, often referred to as the “flat” valve or a “butterfly” valve. This valve serves the important purpose of opening to let just the right amount of air into the intake manifold as you step on the gas pedal.

The higher the pressure on the gas pedal, the more air will flow through the valve and into the intake manifold. However, that’s not the only task of the throttle body. Once the valve opens to let air through, the throttle position sensor reports back to the engine control unit (ECU).

The ECU consequently sends a signal to fuel injectors and determines the amount of fuel injected into the chambers accordingly. The throttle position sensor reports based on how much the throttle body valve is open, and the mass airflow sensor reports the amount of air that flows over it on its way into the intake manifold.

It all happens as you press the gas pedal, so you could say that the throttle body serves a crucial role in engine combustion. If it gets clogged, or the throttle body valve fails, it might result in restricted airflow and poor engine performance.

The impact of the throttle body spacer

As you can probably conclude by the sound of it, a throttle body spacer results in more space where air could flow through into the intake manifold. It elongates the manifold and adds up to an airflow mass that “swirls” and gets introduced into the engine at a faster pace.

This direct airflow is said to enhance the performance of your vehicle in more than one way. Initially, there’s a small gasket between the throttle body itself and the intake manifold. By using a throttle body spacer, you essentially replace that small and thin gasket with a more robust and thick metal ring – a throttle body spacer.

What this does is increase the efficiency of air delivery into the engine which ultimately results in both higher horsepower and torque. Of course, it doesn’t belong anywhere near the debate on different kinds of superchargers like Whipple vs ProCharger or adding a turbocharger.

These are active devices that increase the compressed air intake and they add up to engine performance more significantly. However, that’s the beauty of it – a throttle body spacer is a simple passive metal ring, and it can still boost the engine performance.

Types of throttle body spacers

You should also consider the type of throttle body spacer you wish to add between your intake and throttle body. There are two common types:

• Spiral throttle body spacers
• Smooth or direct throttle body spacers

The difference is slight, and it’s in the design of the interior ring of the spacer. Smooth spacers don’t have anything on the inner side, while spiral ones have spiral-like metal shapes. It adds up to the creation of an air vortex that enters the intake in a different form.

Still, it’s not that much of a difference really, and it also has a lot to do with your stock engine parts when determining the efficiency of throttle body spacers. Some drivers think that a spiral airflow adds up to better combustion, but it’s generally a similar result with each type.

Consider the type of engine first

One of the main downsides of throttle body spacers is that they don’t work as well on modern vehicles with multi-port injection systems. They mainly add the most boost on vehicles with engine types that mix up fuel and air in the throttle body before the mix enters the chambers.

So, getting a throttle body spacer of any type won’t make much of a difference on newer vehicles, but it might add some horsepower to older cars. You could say that the newer engines have optimized air/fuel mixing systems, so the spacer won’t do much difference.

You should also make sure that there’s enough space on your stock intake parts to add a spacer. As mentioned before, it’s a bit thicker than the original gasket, so if there’s no possibility of slightly moving the intake manifold, you might not be able to install the spacer.

Advantages you gain with a throttle body spacer

The throttle body spacer somewhat relieves your engine as it doesn’t have to work so hard to pump the air into the chambers. Increased airflow, especially one of the spiral throttle body spacers should also result in easier air/fuel combustion.

So, it should increase your car’s power by at least 5 horsepower, and it also affects the torque output. It’s not a bad result for a single metal ring placed between the throttle body and intake manifold. Continuous airflow makes the combustion happening easier and quicker, so it might be a decent upgrade for older engines.

Our take

This guide hopefully deals with the question of “what does a throttle body spacer do” in a way that’s easy to comprehend. So, you might be able to install a spacer in your intake system to increase the power and torque output of your engine.

Make sure to also measure the space between the throttle body and the intake manifold, since in some cars just a factory gasket fits in between.