Where does wideband O2 sensor go?
 

What's up guys,

I'm in the process of installing a Vortech S/C in my BRZ and have purchased an AEM wideband O2 sensor with failsafe. Do I have to weld in a separate bung for the wideband sensor, and if so, where should I put it (running a Tomei EL header and Perrin 2.5" overpipe)? Or, does it replace an existing sensor? Thanks in advance for the help!

There's probably a way to put it in place of the rear O2 sensor and disable that second O2 in the ECU, someone in the software/tuning sub forum might be able to help you with that.

You could also add a bung for it, the overpipe would be a good place for it in my mind...

If you're supercharged, you'll be running a custom tune so I'm assuming the secondary o2 sensor will be disabled. I'm pretty sure you can remove it and replace it with your sideband without getting a CEL. The secondary o2 sensor serves no purpose other than confirming if your catalytic converter is working.

You want the wideband before the cat, not after.

OP has a Tomei EL header, he doesn't have a primary cat.

Missed that part. It should be at least 18" from the exhaust ports. AEM widebands come with instructions with some more details regarding placement.

You want it before any cat and as close to the merge point of the header as possible. If on a turbo car, you want it on the downpipe at least 18" from the turbo.

I have a separate bung welded to my overpipe pointing up near the battery for the wideband. It is a very accessible location and I can remove/reinstall the sensor or a plug without removing anything else from the car.

Fantastic. Thanks for the help, guys!