Abstract: An exhaust header system (20) for an internal combustion engine includes primary tubes (22), each having inlet (26) and outlet (28) ends. The inlet ends (26) are adapted to carry exhaust gas (60) from exhaust ports of the internal combustion engine. A collector (24) has a collector inlet (32), a collector outlet (34), and an intermediate section (36) interposed between the collector inlet (32) and the collector outlet (34). The collector inlet (32) exhibits an ovular cross-section, and the outlet ends (28) of the primary tubes (22) are aligned along a width (74) of the collector inlet (32). The collector outlet (34) exhibits a circular cross-section, and the intermediate section (36) transitions from the ovular cross-section at the collector inlet (32) to the circular cross-section at the collector outlet (34).

Abstract: A single-in/single-out exhaust muffler 20 for an internal combustion engine includes a curved inner tube (26), an exhaust inlet (24) in communication with a first leg (32) of the curved inner tube (26), and an exhaust outlet (28) in communication with a second leg (36) of the curved inner tube (26). The exhaust inlet (24) is configured to receive exhaust gas (22) and the exhaust outlet (28) is configured to output the exhaust gas (22). A curved portion (38) interconnects the first and second legs (32 and 36). A sound absorbing material (40) is wrapped around the curved inner tube (26), and a muffler housing (42) encloses the curved inner tube (26) and the sound absorbing material (40). The first leg (32) includes a perforate region (58, 60) and an imperforate region (62, 64) arranged about a circumference (66) of the first leg (32). Likewise, the second leg (36) includes a perforate region (68, 70) and an imperforate region (72, 74) arranged about a circumference (76) of the second leg (36).