It is important to note, however, that going too large may cause a dip in performance when gases pile up and exit the system slower resulting in torque, rpm, and horsepower loss. After the emissions are channeled out from the cylinders by the exhaust manifold, they are deposited into different catalytic converters. The IE Catback Exhaust System for your Audi B9/B9.5 S4 incorporates our in-house engineered DroneTrap technology to deliver a truly aggressive exhaust note without any annoying drone or rasp. Engineered with cutting-edge design features, including mandrel-bent stainless steel, TIG welding, multi-point reinforcements, and oversized quad tips. A catback exhaust system is a type of aftermarket exhaust system that replaces the muffler and tailpipe of a vehicle. It is called a “catback” system because it starts at the catalytic converter, which is located in the middle of the…

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