The part number 18111712064 is a Genuine BMW Exhaust Flange. It is primarily used to connect the exhaust pipeline components—typically securing the seal between the catalytic converter section and the rear muffler pipe assembly. This exhaust flange is widely utilized across vintage 3 Series and 5 Series models powered by M20 (and select M50) engines: (19g)
BMW 3 Series (E30 Chassis)
- 1987–1993 BMW 325i (Coupe, Sedan, and Convertible / 2.5L M20 engine)
- 1987–1991 BMW 325is (Sport Coupe / 2.5L M20 engine)
- 1988–1991 BMW 325ix (All-Wheel Drive / 2.5L M20 engine)
BMW 5 Series (E28 & E34 Chassis)
- 1982–1988 BMW 528e (E28) (2.7L "Eta" M20 engine)
- 1989–1990 BMW 525i (E34) (Early models utilizing the 2.5L M20 inline-6)
- 1991–1995 BMW 525i (E34) (Later variants using the 2.5L 24V M50 inline-6)
Note - I have 2 different flanges which look almost identical. Fortunately, the part numbers are etched on the flange. The 18111712064 is a slightly smaller diameter flange designed to wrap around standard 45mm to 48mm exhaust pipes. It is matched with standard-displacement 4-cylinder and smaller 6-cylinder exhaust tracks. The 18111712070 is a larger diameter flange designed to match thicker 50mm high-flow exhaust piping configurations. It features a broader internal opening to clear large-bore tubing.
