Our Honda Civic Intake system is to replace that factory restrictive air box with a high air flowing intake. Having a greater and colder amount of air into the engines mean the engine breath well, also provide cooler air from the front or side of the engine bay. Increasing the diameter of the air intake, allowing increased airflow. smoothing the interior of the intake to reduce air resistance. Providing a more direct route to the air intake. Tuning the length of the intake to provide maximum airflow at certain engine speeds (RPM). Using a more efficient, less restricting air filter. Cold air provides more oxygen for the engine to burn.