o2 sensor / 95 s-14 ka24 engine

[thehartofthings]

, when i removed my factory exhaust pipe and manifold , i discovered there were two o2 sensors, one at the header and the other after the catalytic converter, , I am replacing the factory header and exhaust, how will deleting one or both of these devices affect my performance

[breadbox]

don't delete the first one for sure, I didn't think s14s had secondary after the cat.

[Raz007]

If you delete the first one, your car will run like a** if it runs at all. The second doesn't really do anything except throw a CE light. When I installed my OBX header, I came across theoe observations. Since my 2nd sensor didn't fit into the supplied hole, I took my car down to a local guy to have it welded in. Well, he misunderstood what I wanted him to do, and installed the small secondary one into the 1st sensor position. Flame city, and car ran like a** except at WOT. So I turned around, got him to do it like I wanted, and all is good. I have the OBX header, cat delete pipe, and the HKS hi power, and no check engine light. And I also passed inspection. Install both, and you'll be fine.

[OutToWinPAHC]

Second is for catalytic converter efficiency. Basically if the cat is not there the reading will be the same and throw a code, if the reads are too far different it also throws a code (clogged cat). Just use a test pipe with a bung, and use a stimulator bend.

[thehartofthings]

i,ve been seeing those test pipe deals on ebay, wasnt sure what they were for, got my m2 downpipe in , discovered it has a threaded hole for 2nd o2 sensor, although it looks bigger than the one at the manifold, so u think i should replace with one of similiar thread like the 1st one , how is this test pipe made, i cant visualize what it can do if its just a straight pipe

[OutToWinPAHC]

A test pipe bolts up where the goes. It's a cat delete, but makes it easy with bolt up flanges and gaskets.