bikesforme

Is it worth de-cat the downpipe on a uk 99 impreza, are the gains worth the trouble of putting cat back on for the mot. If so is it a easy job to do and what are the best ones to buy, and what happens to the sensor thats in the downpipe.
My car has the middle cat off and a performance back box, apart from that its standard and i am getting the power bug but on a budget lol

Shmerman

iTrader: (14)

On its own its not worth it. With a remap then the gains are more inviting.

the downpipe cat is much more restrictive than the cat in the centre pipe so you can (with a remap) exploit that.

Come mot time, if you put the centre cat back on should get it through emissions. Much easier than replacing the downpipe.

Our just get a sport cat downpipe and not worry about emissions. Obviously more restrictive than on open free flowing decat but less hassle.

Shmerman

iTrader: (14)

The lambda sensor goes in the the same place on the new downpipe. most decent ones come with a boss already welded in.