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O2 sensor mount

A

albertaflyer

Active Member
Purchased an SDS EFII from Ross and have been very happy with the whole process. It?s canada day long weekend and I?m sure Ross is busy so I thought I would ask here. So close to flying looking for an answer ASAP. Where are people mounting O2 sensor and can I mount in one tube? I can?t get mine to read unless I creat some back pressure. I?m about 10? from the exit. I have a four into one exhaust and from the 4 into 1 collector is only about 12? long. Any help would be greatly appreciated.
 
I am not flying yet, I mounted mine in about the same location, downstream of muffler on right bank of IO-540. Keep us posted on what you find.

Steve
 
Hey Steve,
Watched a Holley injection system video as I’m sure it doesn’t matter what system or what application, theory is all the same. Minimum 18-24” from tip minimum, no exhaust leaks before or after even as small as pinhole. Best to place right after the 4 into 1 as in my case (which I did), but no where enough exit length. Not sure where to go from here. I really wanted to use existing exit hole out of cowling, but don't want a foot sticking out of cowling.
Added a link below to a couple of pictures.
https://www.overlanderbikegear.com/photo-page
 
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From what I gather, if there is not enough pipe after the sensor you can get ambient air "creeping" up giving false readings. I just can't wrap my head around the fact that I'm getting NO reading at all. I would think it would sense something. That being said, it is reading oxygen in the stream, so if there is just too much it's obviously not going to read anything as in my case. I was thinking a cone on the end to create a bit of back pressure, but after thinking about it, it won't stop the creeping back up.
 
Well don't I feel stupid. After all the video watching and reading on the subject this morning, my brain finally kicked in. I can't have my vaccum line in there like that either because its introducing air also. Oh well, too many long hours.
 
Do you possibly have a bad O2 sensor?

I have a 4 pipe exhaust... (not 4 into 1). I?m not at the hangar right now to measure it but when Clint was building my exhaust I think he said there was a ?standard? place to mount the bung, and I want to say it?s about 6-8? down from the head. I?m not sure what Ross has to say about the ideal location of the O2 sensor, but Robert recommends placing it fairly close to the head. I think mounting it in a 4 into 1 collector will give you the best overall average, but locating it there that close to the exit may not give you an accurate reading. In your situation, are you sure you don?t have a bad sensor?
 
I was curious as to what others with straight pipes or crossovers do. I'm no expert when it comes to this part and if it's ok to run off one pipe and maintain my exhasut the way it is, that would be great. The video I watched by holley said exactly that, that its a little more accurate after the collector as it averages all 4. Bench tested it per instructions with a butane lighter (not lit) and sensor and guage worked perfect.
 
I think you?ll be fine mounting the bung in one pipe. You might want to email Clint and see where he mounts it on a single pipe, as that?s the only option for those of us that don?t have a collector.
 
The SDS 550 installation I'm finishing up will have the sensor about 10" from the tailpipe outlet, only place I could mount it. it is a dual three into one with big (Canada eh) heat muffs & ball joints, Ross figures it should be fine.

My last SDS 360 installation (Vetterman crossover) had the sensor in about the same relative location, it works acceptably but the reading flutters a bit.
 
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We usually recommend the sensor be around 12 inches from atmosphere and at least 12 inches from the port, if that's possible. We want to avoid very high temps on the sensor and air contamination due to flow reversion between exhaust pulses.
 
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