After a year of development, the 8th Gen Civic Si intake is available to the public. This intake is designed to make big gains on any setup, from totally stock to high-lift cams and huge exhausts. A 14hp peak gain and 9hp average gain is possible against the stock airbox. Against competing 3.5" cold air intakes, we saw typical peak and average gains of around 2-3hp with a much smoother power band, meaning more power and better drivability.
One very cool component in this kit is the injection molded air bypass manifold. This manifold serves a number of functions. It provides attachment points for the factory MAF as well as for the (included) silicone tubing that attaches to the factory valve cover vent and air bypass valve. It also has a built-in air bypass feature that allows air into the engine when the intake's filter becomes wet. This helps to avoid the dreaded hydrolock that so many people normally worry about in heavy rain. We tested the bypass valve by totally submerging an air filter in a bucket of water and running the motor.
Also included with each kit is a powder coated steel battery tray that relocates the battery in front of the transmission to make room for this intake's massive piping. We also provide a silicone upper radiator hose to give better clearance than the stock radiator hose.
You will need a tuning software like Hondata's Flash Pro to tune the car after installation. This kit should be run using MAP tunes only.