Cobb Tuning Charge Pipe - BMW 135i/1 Series M/335i (N54/N55)The COBB BMW N55 Charge Pipe both increases flow and improves the reliability of your turbocharged BMW. The 3" mandrel bent aluminum pipe replaces the brittle factory plastic pipe which can fail under increased boost pressure. The increased piping size helps to reduce turbulence and maximize flow into the engine. Note: You may need to source a new O Ring (P N 13717568031) and possibly a new C Clip if yours are missing or damaged as they are not