[lukester01]

I am tempted to remove the catalytic converter completely. I have a friend who made a bolt up piece of exhaust pipe to replace his (on a old car) and when he goes to emissions check place he just bolts the cat back up. Will this work on a 2001 impreza 2.5rs? Or will the computer freak out?

Luke

 

[Warp3]

The 2001 (and late 2000) ECUs tend to freak out over a high-flow cat, much less NO cat. However, there are devices available to fool the ecu connection for the 2nd O2 sensor into thinking it is receiving the correct signal.

Whether the side-effects (both environmental and legal) and extra parts involved are worth the minimal gain over the stock cats (or a high-flow cat) is debatable.

I personally plan to go with a high-flow cat in the future, but I've got one of the less picky MY99 ECUs to deal with.

 

[RST25]

I removed mine a while back. Took the cat off and the pipe after it. Im pretty sure there are two, dont remove the first cat with the O2 sensor. Sounds bitchin.

 

[xtorted-legacy]

I've heard no cat and even some high flow cats on N/A inpreza's loose noticable low-end grunt/torque. I'm not sure tho.

 

[Albert]

Please, be kind to your grandkids run at least a hi-flo cat
For everyday driving and an occasional autocross there might be no performance gains without a cat.