You're right. There were actually 2 write ups on this already and I have both saved:

#1 With Pics: https://www.evolutionm.net/forums/sh...d.php?t=114931

#2 not as clear: https://www.evolutionm.net/forums/sh...ad.php?t=99137

But nice write up. This now makes 3 threads on the same thing, so there shouldn't be anymore questions on this.

 

Ok i got mine to fit....one fouler was really tight......Had to manipulate alittle to fit it. Also it looks like there isn't any sensoring room when the o2 is in the non fouler, snug fit but no tightness......should I grind down more non fouler wall? Someone if anyone can help please.....

Dante`

 

Just drill one out using a 1/5in bit and you will be fine

 

yo this works on audis & vw's too.

 

Is it me, or its a pain in the *** to get the o2 sensor out.

 

ive never done exhaust mods on an evo before so im not familiar with the system. correct me if im wrong but there are 2 o2 sensors on our cars and 1 is in the elbow shaped "o2 housing" that people speak of and the other is at the beginning of the "catback" portion? on my wrx a company called PDE makes a downpipe that has the mechanical o2 sensor CEL fix built into it in the form of a small tube welded onto the top of the downpipe where it meets the catback and it is sort of like this in that it has a small hole accessing exhaust gases so that there is enough of a reading to NOT throw a cel but not enough TO throw a cel. so i guess someone would have to make an extension like that on the catback for it to work. correct me if im wrong with any of this, trying to figure out the best route.

 

Alex,


The WRX had actually 2 cats on the downpipe but yes like you said it was on the upper area. The Evo 8 and the Evo 9 had two different o2 sensors locations and the shape of the cats are also different.

The o2 housing has one of the o2 sensors. Depending on if you have a Evo 8 or a Evo 9 that would determine wre the secondary o2 sensor is located. On the Evo 9 the secondary o2 sensor is located right above the cat which has a flat cut on top of it.

On the Evo 8 the secondary o2 sensors is located ion the rear section of the cat -back.

Do a search on my name, I posted many pics in the past displaying the different locations of the o2 sensors on the Evo 8 and Evo 9.

Carlos

 

I did this mod and followed it to the T....... I had to hammer my floorboard up so the foulers and the sensor could fit.... and it still comes on every now and then... any suggestions?

 

i would check the code first & make sure it's from the o2.....

 

nice write up thanks

 

I did the same thing on my car, works like a charm, easy to do CEL FIX... Great Write Up

 

It has been over 2 weeks since I used this method and it is still working like a charm.

 

worked perfectly for me. great write up.
Although i almost stripped my 02 sensor threads in getting it out the first time.
Be careful not to force it out, when you take off stock cat.

And count how many turns it takes to get out, so you can twist the 02 sensor wire that many times before you replace it in new cat.
That way the wire isnt kinked and not have any pressure on the wire.

drilled hole and screwed 02 sensor in, installed on hi-flo cat.
works great, no codes for 4 months.
and I only used one anti-fouler worked fine.
GL

 

the second spark plug fouler (non drilled) is not needed. I have only the drilled on my car and the check engine light has never came back on.

 

18mm