K&N Cold Air Intake Kit: Increase Acceleration & Towing Power, Guaranteed to Increase Horsepower up to 15HP: Compatible with 5.4L, V8, 2004-2008 Ford/Lincoln (F150, Expedition, Mark LT), 57-2556

How Does a Cold Air Intake Work and Why Should I Replace the One That Came With My Vehicle? In a standard air intake system, air passes through a disposable paper filter and then flows into the engine through a complex system of tubing.

K&N cold air intake systems provide a less restrictive path for airflow, increasing the volume of cool, oxygen-rich air into your engine.

A performance air filter is paired with specially designed tubing and a custom air box or heat shield (engineered to protect the intake air from the heat of the engine), which in combination deliver a guaranteed increase in horsepower and torque.