aFe power introduces an all new Twisted Steel "Street" Down-Pipe for the Subaru WRX STI 2015-2017 with H4-2.5L engine. This down-pipe is designed using a 400 CPSI catalytic converter and mandrel-bent, 304 stainless steel tubing for optimum flow resulting in added horsepower and torque. The down-pipe is 100% hand TIG-welded and uses a 2-1/2" into 3" stepped design that increases exhaust velocity and eliminates low pressure drops which helps to scavenge the exhaust for increased power. In house testing produced a max gain of +22 horsepower and +37 ft. lbs. of torque verified by our in house dyno. This kit includes a second bung for either a wide-band O₂ gauge or auxiliary instrumentation.
This system utilizes a 400 CPSI (cell per square inch) catalytic converter for maximum flow.
2-1/2" to 3" Stepped Design:
A unique 2.5" to 3" stepped design, is used to increase exhaust velocity and increase usable torque. This means more aggressive throttle response and increased passing power.
100% TIG-Welded by certified craftsmen for race proven strength and durability. TIG-Welding provides the strongest welds reducing stress cracks.
Brushed 304 SS Construction:
This down-pipe is constructed of durable mandrel bent brushed 304 stainless steel tubing for maximum performance, corrosion resistance and strength eliminating cracking.
All hardware and brackets are included for a hassle-free installation. This unit also comes with a 2-year warranty.
This down-pipe uses factory mounting locations for the O₂ sensor and includes an additional bung for either a wide-band O₂ gauge or auxiliary instrumentation.
aFe down-pipes are engineered and manufactured in our Corona, California manufacturing facility.
Note: This system is not currently CARB exempt and is not available for sale in California or for use on any vehicle registered with the California Department of Motor Vehicle.