EXPREME 4-1 Unequal Length Exhaust Manifold

The Tomei EXPREME exhaust manifold is a performance-oriented header specifically designed for the FA20 engine found in the Toyota 86, Scion FR-S, and Subaru BRZ. Its unequal length, 4-1 layout is engineered to enhance torque and throttle response. Constructed from SUS304 stainless steel, this manifold features a lightweight and highly rigid stepless flange, with a pipe thickness of 1.5mm. The port exit dimensions at the first juncture are Φ42.7, expanding to Φ45.0, and the second juncture leading to the joint pipe is Φ60.5. The flange thickness is 12.5mm on both the front and rear sides. The collector is made using a lost-wax casting process and includes an O2 sensor boss. The header unit is accompanied by an engine-side gasket, a joint pipe-side gasket, flange bolts, flange nuts, a thermal insulation sheet, and smooth paste. Note that a joint pipe is sold separately and is recommended for even better results. Key specifications include a material of SUS304 stainless steel, a 4-1 layout, port exit diameters of Φ42.7 and Φ45.0, a 2nd juncture pipe diameter of Φ60.5, and flange thicknesses of 12.5mm. Its weight is 6.85kg, significantly lighter than the stock manifold's 9.2kg.