I am installing a new custom exhaust system. The folks who made the catback exhaust pipes, Mandrel Exhaust Systems (recommended by Maxima.org members), also built me a pipe with a bung in it for the O2 sensor that is directly behind the cat. The other end of the pipe will go into the resonator front end.

In order to get it to all fit, I asked them to slant the bung 45 degrees. As I look at it while test fitting, it appears that the tip of the O2 sensor only sticks out into the exhaust stream about half way. All the little holes in the tip are still exposed but they just don't sit in the stream of the exhaust flow.

Do you guys think that is going to be a problem or will the exhaust flow still get into the little cranny enough for the O2 sensor to get a good reading?

 

It will be, uh, good enough

That O2 sensor's purpose in life is to make sure the cat is working. That's it. It doesn't influence the air-fuel ratios like the primary O2s do. The primaries are the first O2s seen by the exhaust as it leaves the combustion chamber from each bank.

 

... give it a try and see what happens.

If no DTC is generated then your car is none the wiser and at least "thinks" it's happy.

 

I would think it would be fine as well as other vehicles sometimes require an anti-fouling adapter for their O2 sensors. The adapter in essence takes the O2 sensor further out of the exhaust gas stream and that resolves their DTCs.

 

I had a machinist buddy look at the bung, suggesting that I take some of the top off so the tip would sit further in the stream and he was concerned about how to get the O2 threads right. You cut into the top and chasing those threads may be hard to do. He had the same suggestion as you.

I had not heard of an anti-fouling adapter before. The fact that those exist would seem to support the idea that having it a little higher in the exhaust stream won't be a problem. My thinking is that it is a mixture of gases that are being measured and they will go anywhere they can, even up into the bung area.

Thanks guys!

 

Thanks dwapenyi. I sure hope you're right!

 

I wanted to report that I was able to do some tin work around the heat shroud above the catalytic converter so the O2 sensor fit great. The car started and ran well and passed emissions testing fine. It took awhile to get the car running well though due to some fuel injector issues but now that is all behind me and the car is really fun to drive. Thanks again to all the Maxima.org members.

 

Glad to see everything is working out well. Nice reports RB.