aFe POWER introduces an all new Twisted Steel "Street" down-pipe for the 2012-2015 Honda Civic Si (Coupe/Sedan) with I4-2.4L VTEC engine. This header 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. In house testing produced a max gain of +8 horsepower and +7ft. lbs. of torque verified by our in house dyno. This down-pipe is 100% hand TIG-welded and uses a 2-3/4" into 2-1/2" stepped design that increases exhaust velocity and eliminates low pressure drops which helps to scavenge the exhaust for increased power. This kit also includes a heavy duty 4" flex tube with an internal interlock liner for added strength and durability.

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

2-3/4" to 2-1/2" Stepped Design: A unique 2-3/4" to 2-1/2" stepped design, is used to increase exhaust velocity and increase usable torque. This means more aggressive throttle response and increased passing power.

6" Interlock Flex Pipe: This unique down-pipe uses a heavy duty 6" flex tube with an internal interlock liner for added strength and durability.

TIG-Welded: 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: Includes an O2 sensor extension harness and a lower flange gasket for a hassle-free installation. This unit also comes with a 2-year warranty.

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 down-pipes are engineered and manufactured in our Corona, California manufacturing facility.