If you've modified your engine beyond the basics, it may be time to consider upgrading your Scion XD intake manifold to a high performance version, which will feed more air to the engine's cylinders and will result in more power. Installing a new Scion XD intake manifold is one of the best ways to increase engine efficiency, as well as one of the easiest. Most intake manifolds can be installed in a couple of hours, and are an obvious sign that something serious is going on under the hood.

Much like camshafts, Scion XD intake manifolds are designed to work best within certain RPM ranges, and provide more oxygen to your engine for an increase in power and performance. Intake manifolds can run the gamut from very affordable to somewhat expensive, but the price discrepancy is largely due to the research and development, not to mention proven results, from the leading manufacturers. Depending on the design, some Scion XD intake manifolds might require hood modifications due to their increased height, but in general they should fit under a stock hood with no problems.

Q: What is an intake manifold? Why buy an intake manifold?
A: Air is routed through the air filter, through the throttle body or carburetor, and into the intake manifold. Once the air is inside the intake manifold it's distributed to each of the cylinders in equal parts. In order to increase the capacity of the intake manifold so that it carries more air into the motor for combustion, many people buy performance intake manifolds that incorporate a larger chamber where the air collects into the manifold. More air equals more power. So if you want more horsepower, an intake manifold is a great way to go about getting it.

Q: How do you install an intake manifold?
A: It depends on whether your car is carbureted or fuel injected, but either way, the good news is that it's located on the top end of the engine and therefore is easily accessible and won't require you to mess with any internals to change it out.