aFe Power introduces an all new Twisted Steel Header for the 2004-2015 Subaru WRX STI with H4-2.5L engine. In testing, this header produced a max gain of +9 horsepower and +13 ft. lbs. of torque verified by their in-house dyno. These headers are constructed of near equal length mandrel-bent 1-5/8-inch into 2-1/2-inch 16-gauge, 304 stainless steel tubing and uses 3/8-inch thick flanges for strength and to ensure a leak-free seal. The smooth curves and increased diameter of this header helps remove restriction and keeps exhaust gas flowing smoothly for improved performance and durability. To eliminate dead space that can cause turbulence and hinder flow, a 4-to-1 formed collector and optimized tube lengths are used. This combination helps increase exhaust velocity improving flow, as well as horsepower and torque improving throttle response. This system retains factory mounting locations and requires no modification for a simple, hassle-free installation.
- Constructed of 1-5/8-inch into 2-1/2-inch 16-gauge, brushed finish 304 stainless steel tubing
- Incorporates a 4-to-1 formed collector
- 3/8-inch-thick laser-cut flanges
- Retains factory sensors
- Optimized near equal tube lengths improve flow and performance
- 100% TIG-Welded by certified craftsmen for race proven strength and durability