How to Install an Intake Manifold Spacer

For the sports car enthusiast, an intake manifold spacer is another way to increase horsepower and performance. Since a vehicle’s intake manifold sits directly on top of the engine, putting an intake manifold spacer between the engine block and the manifold will keep the manifold cooler. The cooler air in the manifold is denser, and as the denser air is forced into the engine cylinders, it provides more oxygen for the combustion process. This leads to an increase in horsepower. An intake manifold can also be known as a throttle body.

Most intake manifold spacers come in 1 of 2 sizes, 3/8 inch and 1/2 inch. Buy the biggest spacer you can, and still have room for the hood to close.

Tools and Materials

  • Intake manifold spacer
  • Intake manifold spacer gasket
  • Socket wrench and sockets
  • Screwdrivers (flat and Phillips, if necessary)
  • Towels

Step 1 – Preparing

Open the hood of your vehicle and locate the intake manifold. It should be located on the top and center of the engine. Disconnect the negative battery cable and set it away from the battery and any metal in the engine compartment. Place a towel over the fenders of your car, so you don't scratch the paint as you lean into the engine compartment.

Step 2 – Removing the Intake Manifold

Remove the air-intake hose assembly from the manifold and set it aside. Remove the throttle cable, vacuum lines and electrical connections from the fuel injectors and fuel rails. Then, loosen the bolts connecting the intake manifold to the engine.

Lift the intake manifold and move it out of the way, to make room for the intake manifold spacer. Be sure no debris falls into the engine block.

Step 3 – Installing the Intake Manifold Spacer

Place the intake manifold spacer and its gasket in place on the intake manifold. Put the intake manifold back in place on top of the engine and bolt the new assembly in place.

Reinstall the throttle cable, electrical cables and any vacuum lines you removed. Be careful when reinstalling these cables and hoses, as you may have to stretch them a bit since the intake manifold is now slightly taller.

Step 4 – Securing the Assembly

With the intake manifold securely back in place, and all the cables and hoses reattached; you can now reinstall the air-intake hose assembly. Orient the hose assembly, so all the hoses and connections are able to get reconnected as well. Secure the assembly in place with any clamps and screws.

Step 5 – Tightening all Connections

Reconnect the negative battery cable and tighten it securely to the negative terminal. Remove the towels from the fenders and start the car. Check for any leaks from the air hoses and/or fuel lines. Tighten any connections that require it, before closing the hood.

And that's all there is to it. Depending on the size of the intake manifold spacer you installed, you can expect an increase of between 2 and 7 rear-wheel horsepower. It may not seem like much, but with other aftermarket options, these increases will soon add up to some serious improvements.