AFR: Pictures of Bung Placement Please

[PaulTWinterton]

I'm looking at installing an AFR device and would like to see pictures of optimal bung placement in the downpipe.  Opinions as well.

 

I've searched "AFR" and getting no pictures of the bung.

 

Thanks,  Paul

[jgerock]

Paul- search for wideband o2 sensor location

[Chester]

Ummm...  I think you should put NSFW in your header for this subject matter 

 

Sorry - couldn't help myself but I too am interested in the answer to your query...

[Stevenc22]

Here is mine. If I were to do it again I would move it 4 inches closer to the collector. You need it after all the runners merge and the air flow settles.

[torquewrench80]

I recently purchased an Innovate Motorsports unit, # 3855 MTX-AL analog kit. Their instructions state at least 24" behind the collector, so with a stock downpipe, 24" aft of where the two pipes merge into one.

[Stevenc22]

I think it's 24 inches from the exhaust port, but after the collector.... Not 24 inches from the collector. 

[torquewrench80]

10 minutes ago, Stevenc22 said:

I think it's 24 inches from the exhaust port, but after the collector.... Not 24 inches from the collector. 

"Weld the bung at least 24 inches downstream of the exhaust port outlet (after the collector), or 24 inches after the turbocharger if so equipped." Yeah, you are probably correct there Steve. I thank you for bringing that to my attention. I wonder if it would matter mounted further back. There are late model cars in use with O2 sensors quite a ways back from the engine. I'm reasonably sure it will get hot enough to activate the sensor. It states in the instructions not to exceed 500C/900F degrees of the sensor. I think the key words are "at least." I may contact them just to make sure. 

[Simeon]

The sensors will work (after a fashion) if installed in a dummy piece of pipe and temporarily inserted into the tail pipe. Definitely better to permanently install closer to the engine as you minimise chances of the readings being corrupted by air leaks, condensation etc. The change in reading is also 'delayed' as it takes longer (slightly) for the gas to propagate to the end. If you are logging the values then this could throw you off course. The bung should be installed in the top half of the pipe so that it doesn't end up sitting in any puddles of condensation. 

 

This is all 10/10ths stuff so probably doesn't make that much difference for hobby applications. Practical terms, installing it in the header / downpipe near the end of the gearbox is best as you have clearance for the sensor/ wiring and you won't need to disturb it if you pull the resonator for maintenance work. 

[Chris_B]

Here is one example.

[Ncbimma]

^  what did you spray the weld with after? Or was this bung chromed in..

 

I'm about to weld my wideband in too...

Edited August 26, 2017 by Ncbimma

[Chris_B]

I am not sure I understand your question- probably because I am generally ignorant about welding/metallurgy. This is not chrome, it is Jet-Hot. The coating was applied with the bung plug in place. Not sure about spraying the weld beforehand. Pls elaborate.

[Dudeland]

My AEM said at least 12" after the collector, mine was installed around 8" but it works fine, It does jump around a bit, not sure if that is due to location or tuning, but it definitely works to dial in your carb.  

[PaulTWinterton]

Excellent info.  Thanks.

[AustrianVespaGuy]

A few other important notes, you want the sensor somewhere in the TOP half of the pipe (aka between 9 o'clock and 3 o'clock), so that condensation does not collect in and subsequently kill the sensor. Also, I've found that it's easy for 2002s to kill wideband O2 sensors with too much heat, so I would advise to go a little further downstream and/or install and additional heatsink if you run into this issue.  After killing two sensors after only 18 months each, here's the part I use.  Pricey, but so are new Bosch O2 sensors. . .

https://www.amazon.com/Innovate-Motorsports-3729-Heat-Sink-Extender/dp/B000CO9MFI

 

Oh, and fyi, here's mine at the ass-end of my Supersprint headers, prior to adding the heatsink:

Edited August 27, 2017 by AustrianVespaGuy
Added installed pic

[Doug Riparetti]

This is the location on my S14 header for my "02"