StealthBox Cold Air Intake

The GrimmSpeed StealthBox Cold Air Intake system was developed to enhance the performance and acoustics of the 2015-2021 Subaru WRX. Inspired by the F-117 Nighthawk, its heat shield offers a stealthy look while effectively shielding the MAF sensor from engine bay heat, ensuring more accurate readings and increasing overall performance. The intake tube is constructed from 6061 aluminum with a 1/8 inch wall thickness and features a low-bend-angle design to minimize restrictions. Key specifications include a +32wtq (14.3%) and +21whp (9.6%) increase at specific RPMs, as verified by dyno testing. The design optimizes MAF sensor placement, bend angle (74 degrees total), and filter location within the fender, utilizing the factory ram-air scoop for a continuous supply of cool air. This enclosed cold air intake system combines the benefits of a traditional cold air intake with the protection of an airbox. Included components consist of a CNC-bent intake tube with MAF flange, a GrimmSpeed high-flow dry air filter, an aluminum heat shield, a 12" MAF harness extension, a silicon hump coupler, worm gear clamps, rubber gasket material, and MAF sensor screws. Installation requires tuning as it is not compatible with the factory tune or off-the-shelf maps. Proper tuning is essential after installation to maximize gains and ensure engine safety.