Is replacing the 2nd CAT and resonator (3rd) section going to cause me any problems?
As the O2 sensor goes into the 2nd CAT section.

I have the sports CAT downpipe but would like some burble as it provides none.
Just don't want to cause myself any headaches.

Its on a 53` STI Type UK PPP

Cheers

 

Its not an 02 sensor (thats in your headers), its a cat on fire sensor. Think most de-cat pipes allow you to bolt the sensor in avoiding any problems

 

Will it need remapping? There was a thread some time ago about it making the engine run lean?

 

Not sure, mine was part of the PPP so was mapped to suit. But I think you dont require a remap for removal of the 2nd CAT. Im sure someone will be along to confirm it

 

On a 53 STi, the sensor in the headers is the primary 02 sensor.
The sensor in the 2nd cat is a check 02 sensor.

Since you've got a PPP, the 2nd cat is already removed, its just that the cat shaped heat shield has been put back.

I'm surprised you can't hear the burble - but to get more will need a less muffled back box, an straight through centre section and possibly a decat downpipe.
Try the first two parts before the decat, as they are unlikely to raise a CEL for the check 02 sensor.

Nick

 

I hear it from outside if someone else is driving it, but just want a bit more I guess.

I'll try the centre section first getting rid of the resonator box and see what the result is. Dont really want to do the full decat and then mess about near MOT time. But needs muct I guess.

Cheers