Thanks a lotslvrsleeper said:Hollowing out the stock catalytic converter basically removes the restriction in airflow imposed by the catalyst which may free up about 2 hp. Unfortuneately it also screws up the emissions system on your car and can cause all sorts of other problems. A high flow cat will give you the horsepower gains without the sacrifices Watson80 is right.
The high-flow cats just use one block of honey-comb instead of two. This still gives the all-important back-pressure, but allows it to breathe a little better.DAILLESTWUN said:How exactly does it work? What is the difference if u get a hi flow or just hollow out the stock cat???