O2 simulator is very complicated. You need PhD in Electrical Engineering to mess with it. Otherwise, there's a risk that your car might explode.

 

To frofro24:

To clear up:
Primary O2 is the guy who checks for effectiveness of the pre-programmed fuel/timing map in the ECU under the given set of environmental variables: temp, humidity, baro pressure, load, etc.

In OP's case, that's not affected by hollowed out cat/test pipe.

The secondary O2 is the one that checks the exhaust gas' carbon monoxide content against the same reading by the primary O2. If the secondary O2 shows less, then the cat did its job, and all's quiet.

Put a test pipe on, and there won't be the expected reduction in carbon monoxide at the secondary O2. Because of EVAP, EPA, and the tree-huggin' hippies' requests and requirements, that means you're a "damn air-pollutin', smog-creatin', soot-producin' varmint" in their book. CEL comes on, and your car is supposed to be 'Check Engine-ed'.

Hollowed-out cat, BTW, according to Import Tuner and their Dyno testing, does _not_ gain HP. It's because of exhaust gas turbulence inside that chamber.

So, OP, get a set of headers, and have the shop custom-make a header-back exhaust for ya! Then it's worth it!

 

I thought the secondary o2 sensor was on the cat, and I thought that is the one that pulls readings for air to fuel. I guess I am not to sure why what I wrote needed to be cleared up. I guess I was a little vague on the o2 sensors job.

 

really now... another testpipe thread? ugh

 

just do it!

 

Thank you frofro24, Kirpich , EVAN&MONICA...almost convinced to go for it !

Vik2000: have seen some of your old threads where you seemed pretty keen on a test pipe. Did you do it cos your post on this thread seems like you're pretty scared of it ?!

S2Kage: yeah, sorry, another testpipe thread...but my topic was "Catalytic convertor removal for power gain " and I did not know that its replacement is called a testpipe !! Anyways, I have found info in this one which I haven't found in the many others that I've browsed.

Thank you all for your support.

 

If your not on a real tight budget, consider the HFC from Berk. Only a slight compromise and no antifoulers needed.

 

Oh, it's inside between the 2 banks. It takes a reading after the exhaust gas passes the first one.