I'm about to fit a new exhaust to my STI 7, changing the rear box, centre section and the CAT pipe.

http://www.scoobyworld.co.uk/new_age...ust_system.jpg

I'm thinking about swapping the downpipe with a De-cat while I'm under there too. (29 months until I need MOT! :D)

I take it the unit I'll need to fit to stop the Check Engine Light goes in the downpipe??

If I do fit the downpipe, and don't get my ECU re-mapped for a while, what problems will I get?

Lastly, does the up-pipe have a CAT in it?

Cheers for any info...

[Edited by H18JGM - 11/27/2003 4:19:08 AM]

[Edited by H18JGM - 11/27/2003 4:20:39 AM]

I'll answer as no one else has.. but I THINK the CEL fix is only need for the uppipe.. but not sure if the STI 7 has a cat in the up pipe.. but 90% sure the cel fix is for the up pipe.. just not sure if it applies to the STi or not.

JGM :)

In your car the CEL fix is for the cat in the down pipe as STI7 doesn't have a cat nor EGT sensor in the up pipe (fortunately).
The rear O2 sensor is in the "cat pipe" as shown above in your diagramm and AFAIK you'll not have any problem without the fix except that you can't see any other error codes as your CEL will stay always on, not good which ever way you look at it!
The only problem I have heard so far with full decated STI7 is boost spike in high rpm area that can - probably - prevented with different size restrictors (or adjustable restrictor valve) in "T" piece from inlet manifold to wastegate. In worst case you need turbo porting, hope others can help you more...
JIM

Looks like Jim has answered you :)

Tops

JGM :)

Cheers Guys!