Herein an exhaust manifold (2) is disclosed. A first inlet passage (8) connects to a main passage (12) at a junction. An intersecting wall portion (20) between the first inlet passage (8) and the main passage (12) forms an upstream end portion of the junction. A first portion (22) of the first inlet passage (8) has a first inlet passage cross sectional area (24). The first inlet passage cross sectional area (24) is smaller than a second inlet passage cross sectional area (28) of a second portion (26) of the first inlet passage (8) upstream of the first portion (22) of the first inlet passage (8). The main passage (12) comprises a first main passage portion (30) at the intersecting wall portion (20). The first main passage portion (30) having a first main passage cross sectional area (32). The first main passage cross sectional area (32) is smaller than a second main passage cross sectional area (48) of a second main passage portion (40) upstream of the junction (18).
