O2 Sensor Relocate issues?

[LikeUCare]

Hi All, I have a 94 SS that I am fixing up. I picked up an M2 WRX turbo back exhaust with cat the other day for 180$ (Thanks Craigslist). I have been comparing and reading through the post and I have a question. I did a search but no clear answer

The stock ej22t has the O2 sensor right behind the turbo. The aftermarket WRX exhaust has it after the cat in the midpipe. Normally if the O2 bungs didn't line up I would just extend wiring and call it good.

However since I would be moving the O2 sensor from before the cat to after the cat, is there any impact to the O2 sensor? Should I just get another O2 sensor bung installed and cap the existing?

Thanks for the input, alot of good info on this forum.

[cj91legss]

You should get another bung and cap, HOWEVER.... I have had 3" exhaust on my car (WRX Turboback and some welding done by me) and i have had my O2 Sensor in the stock WRX Location for about a year now. No Issues that i can think of.

[Legacy777]

The difference between the WRX and the turbo legacy is that the WRX has an O2 sensor in it's exhaust manifold. This is the one it uses to adjust AFR's. The second on in the mid pipe is just a cat efficiency check.

You should add a bung to the top of WRX downpipe so you can use the stock O2 sensor setup.

[LikeUCare]

Thanks for the input guys. I am going to install a new bung. Its a little more money but I rather have AFR metering as close to the engine as possible.