Secondry Cat?
 

Afternoon all,

right just purchased a scorpion centre section and TSL back box for my 2001 wrx, got a party potentially interested in having my old japspeed catback.

upon jacking the car up i noticed the "secondary cat" is rotting at the join and is blowing.

so im on the hunt for a replacement so i get on to import car parts to try and source a replacement to which i get told its not actually a cat its a silencer and only place you can get new is from subaru? obviously where ever you look you can get hold of "de catted" sections with easy which is great but im under the impression that i will need a map to compensate? but as it stands im not in a postion just get a remap done.

i drive the car daily so im in a bit of a hurry to get it sorted

can anyone clear this up for me?

That is definitely a cat and not a silencer.

You will not need a remap as long as you have the stock down pipe in place as it's very restrictive.
The ECU can cope with the change as long as you have a decent panel filer to allow the engine to breath.

I removed the 3rd cat for a straight through pipe on my 2005 wrx, althought it also has the uppipe cat I doubt that really makes too much difference in the realms of things.

I got a code reader and checked all the values after removing the 3rd cat in my case and all the values are still ok, it's not running too rich or too lean, and it makes the car easier to drive, spools a bit quicker. Also, no boost creep.

The only thing too mention is your exhaust will be noticeable louder after removing the Seconday cat.

when you say secondary cat - do you mean the 3rd cat in a WRX?

1st is uppipe
2nd is downpipe
3rd is on the flat section

http://i20.photobucket.com/albums/b2...st-diagram.gif

As the rear cat is after the o2 sensor you can feel free to bash it out and replace the flange with whatever you have handy. Because its after the sensor the ECU can't read what it's doing so you won't get any codes or whatnot.


The uppipe cat is far more dangerous and you should consider binning it whenever you can, if it breaks up and lands in the turbo you could end up losing the engine! You can replace it with a fancy one off ebay, a stock STI pipe or a stock pipe off a classic (neither of them had cats). Or you can remove it, bash the cat out and stick it back on.
The primary cat is enough to keep the emissions right (so far as the ECU is concerned) - you'll gain some free HP from the reduced restriction to boot.

the rear cat, where the centre pipe joins to. so i can de cat that section with out any issues?


my long term idea was a full de cat and map but i was hoping to collect bits save a few quid first
bludgod- so let me get this right i can bin the catted up pipe and rear cat and it wont throw CEL over boost f*** up the fueling etc?

Anyone got one for sale?

You don't have an Up-Pipe cat in your car, only WRX models in years 2001 to 2005 have them.

Edit** (My bad, thought it was 2003 to 2005)

So you do have 3 Cats in your exhaust system.
As long as you get a replacement pipe with a hole for the O2 Sensor to fit into you'll be fine.

Hope this explains a bit more

http://www.subaru4you.co.uk/images/i..._schematic.gif

This is the replacement with the hole on top for the sensor? :wonder:


http://www.haywardandscott.com/subar...-cat-pipe.html

http://www.haywardandscott.com/catal...128/image/118/

Edited my above post, 2001 - 2005 wrx's have 3 cats.

You can ditch the 3rd cat (Scrubber cat) with no adverse effects, just a bit better spool and drive.

I have one if needed.

cheers for your input guys, ive ordered a scorpion section to mate with the centre section.
you say it would be noticeably louder with it removed? how loud?
am i going to be p*****g of the neighbours with de cat section, non resonated centre and TSL group N box?