Adding a Subaru Legacy plenum spacer is an easy way to give your ride a slight edge over everyone else's, and does so in a way that's subtle since it can't be seen once installed. Installing a Subaru Legacy plenum spacer certainly won't cause your ride to give you whiplash, but it will provide a noticeable improvement in low to mid-range power and torque, and will often result in improved fuel economy as well.

As simple as they are, Subaru Legacy plenum spacers can yield a dramatic improvement in throttle response and power. By effectively increasing the intake plenum volume and lowering intake temperatures via thermal gaskets, Subaru Legacy plenum spacers can really give your ride a nice boost with minimum hassle. Plenum spacers are usually made of aluminum or plastic, with the aluminum versions using the aforementioned isolating gaskets and others being completely made of a thermo-isolating composite plastic.

Q: What is a plenum spacer? Why buy one?
A: Plenum Spacers mount between the intake plenum and the motor and are designed to increase the velocity of the intake charge which improves efficiency. They also have the secondary effect of keeping the intake charge cooler which in turn helps to improve power. The nice thing about this modification lies in its simplicity. Intake plenum spacers are affordable, simple to install, and a stealth modification that cannot easily be seen. With modest horsepower and torque gains it may not transform your vehicle into a rocket ship, but it will certainly provide noticeable gains that will help on the street and track. In addition plenum spacers improve efficiency and can increase your miles per gallon as well. For such a simple design, plenum spacers provide many benefits with hardly any down side.