Cat. Converter

If you cut a cat. converter off of a car that may be clogged and replace it with a piece of pipe from autozone will it run better? Also will it make the exhaust louder even with the muffler attached?

If your car is designed to run with a cat. then removing it will cause problems if you have a computer controlled car. If you are concerned about better flow to scavange exhaust replace it with a high flow cat. This will do the same job as removing the cat and replacing it with a straight pipe although it will cost more. But it may save you a lot in the long run.

yes thats good advice, DONT remove the cat and just put in a piece of pipe, i did this with my 93 sse and it ran terrible, was really loud (not even a good loud) and my gas mileage dropped to about 18 m.p.g. on the highway.

It depends on the car. If you have OBD II EFI system (required after 1995 or so, the car won't run properly. However, if the car is older, removing the cat will not harm the way it runs. OBD II systems usually have an O2 sensor downstream of the cat. Older systems do not.

The car will be louder though.

Realitically, converters are pretty cheap these days. If the old one has gone bad, help save the air we all breathe and install a new cat.