car: 00' Civic EX

so i just ordered an apexi ws2 exhaust and i have a high flow Carsound/Magnaflow cat i'd like to use, only it's obd1. obviously my car is obd2 and therefore i have a bung in my cat for the 2nd o2 sensor. my question is what can i do about the second o2? i'm just not sure (technically speaking) why it's located in the cat. my headers have 2 o2 bungs. would i be able to use those for both? does this 2nd o2 need to be in clean air? can i have a bung welded into a stainless cat? i would rather not be cutting/welding my new exhaust obviously and having these pieces fit snugly kind of eliminates the ability to put a test pipe before or after the cat with the bung. any ideas?

 

bump, anyone?

 

The second O2 sensor measures the efficiency of the catalytic converter. Just have a bung welded downstream of the catalytic element. Any exhaust shop can do that for you.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dartanian &raquo;</TD></TR><TR><TD CLASS="quote">The second O2 sensor measures the efficiency of the catalytic converter. Just have a bung welded downstream of the catalytic element. Any exhaust shop can do that for you.</TD></TR></TABLE>

i'm not planning on putting a bung on my ws2 piping. it would have to be in the cat and the cat is 100% stainless. i asked at the place i ordered my ws2 from and they said they have steel bungs, but they werent sure if it would even weld to stainless. i'm a metallurgic newb so i don't know how that works.

 

You can weld mild steel to stainless steel.