Second O2 bypass (after cat / catalytic converter delete)

[Wolfman AK907]

Well, you're in WA...I would put a bypass on just in case. For the money you'd spend on it for peace of mind I'd do it.

[MacFady]

I'm planning on getting a "highEST flow cat" possible, i.e. piece of pipe the same diameter as the pipe before/after the cat with two flanges to fit that in there
Edit: just found out that what I'm having ideas about is called a "test pipe".

Ha, before I saw your edit I was just going to say you're looking for a testpipe.

[MetroMPG]

Bumping this 11 year-old thread with a related question that someone sent me via email.

I don't know the answer, so putting it out there for the community...

It's me again

i want to know how many o2 sensors my chevy aveo 1.5 2006 has. I only see the one on the manifold. I looked if i have 2 but i cant find the other one. I am just bit confused why my engine light will go on at the 1st o2 sensor to my cat (i took that white honeycomb out of my cat)
Hope you can help

[Melveo]

you need an anti fouler. it will hold the CEL light off long enough for monitors to set and to pass emission inspection. only a few bucks and need to be drilled out to fit the o2. anti fouler restricts the amount of exhaust flow the o2 can read. Ive been doing mines like that for 2 years now. my cat is gutted and im full straight pipe