Your factory (OEM) catalytic convertor or CAT is probably the most restrictive part of your Audi 2.0T A4's exhaust system. This Evolution Racewerks test pipe is a small part, however it makes a world of difference. With the stock CAT the exhaust gas must pass through a restrictive honeycomb like pipe, which not only slows down the gas but also creates turbulence. This hinders the performance drastically and especially if you have changed out other parts of the exhaust. This Evolution Racewerks test pipe replaces that with a smooth flowing stainless steel pipe. With this pipe there is no exhaust restriction, releasing the gas more efficiently and putting down more power!CAUTION: This product is intended for OFF ROAD USE ONLY. Use of this product upon public highways is prohibited.
The Evolution Racewerks Test Pipe's 3" to 2.5" design is superior over other test pipes that are 2.5" in diameter from inlet to outlet because the 2.5" test pipes will have a "step" right at the outlet. Since the OEM K03/K04 turbos have a turbine (exhaust) outlet of almost 3", the flange of the 2.5" test pipes will actually make a "step" right at the turbo outlet. This step acts like a wall against exhaust flow and when the exhaust hits it, major exhaust turbulence is created, at the worst spot possible, right at the outlet of the turbo. If you have a 2.5" test pipe, check it out. Look at the inlet flange and you will see a "ring" of carbon deposits on the flange. This is the "step" that the exhaust flow is hitting. |