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FE Power Forums => FE Technical Forum => Topic started by: cleandan on June 26, 2021, 10:25:19 PM

Title: Temporary, tailpipe mounted O2 sensor location?
Post by: cleandan on June 26, 2021, 10:25:19 PM
I will be making a temporary tailpipe mounted O2 sensor holder and am wondering how deep into the end of the temp pipe does the sensor need to be?
1", 2", 3"? I don't know.

This sensor hook up will basically be a smaller section of pipe that slips inside of the existing tail pipe, with an O2 bung welded to it for mounting the O2 sensor.

How much extra pipe should I have to keep any unwanted air from screwing up what the sensor is reading?
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: Gaugster on June 26, 2021, 11:01:11 PM
I am not entirely sure about the depth but 1" is about what you see on a 2" diameter exhaust pipe. Perhaps deeper if the overall diameter is larger. What type of 02 sensor is it? The basic (1 wire) type need heat to work and aren't suited for a remote exhaust location. The multi wire sensors or more correctly stated "A/F sensors" are self heating.
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: 6667fan on June 27, 2021, 07:35:34 AM
That is quite a bit downstream. Generally they are placed after or in the header collector. I have to wonder if the sensor is close to outside air if it could be influenced also. I saw that you indicated temporary, are there plans to put it in another location later?
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: HTM101 on June 27, 2021, 07:53:09 AM
I did a Google search using     wideband o2 sensor location

You'll find a variety of answers to your question doing the same search.  Most of the info is provided by individual manufacturers of wideband devices.
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: cleandan on June 27, 2021, 10:59:10 AM
That is quite a bit downstream. Generally they are placed after or in the header collector. I have to wonder if the sensor is close to outside air if it could be influenced also. I saw that you indicated temporary, are there plans to put it in another location later?

This will be an additional part to my LM2 wideband tuner kit.
I use this kit as a tempory tuning tool when dialing in an engine/carb.
I install the sensors, drive around getting readings, tune, repeat until good.
Normally I insert the sensor into a O2 bung that has been installed near the header/manifold collector.

Sometimes, however, there is no O2 bung in the exhaust system making a tail pipe installation the best bet.
Yes, I'll need some extra sensor cable (already part of the kit)
But if the sensor can be in the exhaust stream, and not be influenced by any incoming air, I think I can get good tuning information so long as I have the tailpipe sensor installed correctly.

I am thinking 3" of pipe, past the sensor, will be sufficient to keep outside air from influencing the sensor.
The pipe is stainless steel, 1.5" inside diameter that has a bung welded into it to put the O2 sensor in the right spot.
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: jayb on June 27, 2021, 11:48:32 AM
I'd get one of these:

https://www.innovatemotorsports.com/xcart/exhaust-clamp-p-n-3728.html
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: GerryP on June 27, 2021, 12:53:20 PM
I'd get one of these:

https://www.innovatemotorsports.com/xcart/exhaust-clamp-p-n-3728.html

I use one of those for pipes without a bung.  They work fine even with the car in motion.  It looks strange with a cable taped to the car going down the road but you gotta' do what ya' gotta' do.
Title: Re: Temporary, tailpipe mounted O2 sensor location?
Post by: Phil Brown on June 28, 2021, 10:50:21 AM
We just took a threaded bung for the sensor and welded it to a pair of needle-nose vice grips, clamp it in the end of the tailpipe (with said cable taped to the side of the car 🙂 ). Never had any problems and saved a few bucks in the process