aFe® (15-21) WRX STI Twisted Steel™ 304SS Downpipe

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  • Regular price $879.00

Compatible: (2.5L)

2015 - 2021 Subaru WRX STI



aFe power introduces an all new Twisted Steel "Street" Down-Pipe for the Subaru WRX STI 2015-2019 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 unique fabricated bellmouth 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.

Catalytic Converter:
This system utilizes a 400 CPSI (cell per square inch) catalytic converter for maximum flow.

Fabricated Bellmouth Design:
A unique fabricated bellmouth design increases exhaust velocity providing a free flowing wastegate.

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.

Hassle-Free Installation:
All hardware and brackets are included for a hassle-free installation. This unit also comes with a 2-year warranty.

Auxiliary O2 Bung: 
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.

Race Disclaimer:
This is a Race Only product that is to be used solely for competition, it cannot be used on vehicles that are operated on public streets, roads or highways. Its use is limited to closed-course and open-course racing that is formally sanctioned by a recognized racing organization. Any other use, including recreational off-road use, could be in violation of local, state and federal laws. To complete the purchase of this item, aFe Power competition acknowledgement/liability release form must be filled out and submitted.

aFe POWER down-pipe are engineered and manufactured in our Corona, California manufacturing facility.



Install Guide: