8th Gen Civic SI 4-2-1 Tri-Y Header with Test Pipe

The K-Tuned 8th Gen Civic SI Header is a performance-enhancing component designed for the K20Z3 engine found in 2006-2011 Honda Civic SI Coupe and Sedan models. This header utilizes a 4-2-1 Tri-Y design, aimed at delivering power gains across the entire power band, not just at high RPMs. It is constructed from 409 Series Steel with CNC-cut 3/8" thick flanges and a 2.5" outlet. The design incorporates large diameter piping, stepped tubing, and smooth transitions to minimize exhaust gas restriction and improve flow. The header replaces the OEM 2-piece design and eliminates the catalytic converter. It comes with a short 2.5" test-pipe and a defouler for the secondary O2 sensor. Installation notes recommend upgrading the rear engine mount to a Hasport rear mount to limit engine movement. The donut gasket can be replaced with an OEM Honda part (18229-PCX-003), reusing the metal ring.