Side Pipe O2 Sensor Location

[Bobby Doug]

Installing Holley Sniper EFI. Has anyone put an O2 sensor in the side pipe? I know this goes against having the sensor pointing down. If so, have you run into any problems? The other 2 options are reading only a single cylinder or buying new headers. New headers are not a player right now.
Thanks,
Doug

[RJD]

Here's an earlier thread on the topic. Hope it helps.

https://thefactoryfiveforum.com/showthread.php?29783-Where-Did-You-Put-Your-Roadster-O2-Sensor-Bung

[Bobby Doug]

Thanks, I had just read the same post after a google search. I tried searching on the forum and was getting frustrated. I had forgotten about google searching and remembered after the post. Still interested if anyone who has mounted their O2 there and if any issues.
Thanks,
Doug

[GWL]

I have seen them located down there a while back. Possibly predates this forum. Note that to work properly the sensor has to be hot, thus why they have heated sensors to aid in warm up running. The further away from the engine the cooler the sensor will be. Is it hot enough during normal running to work properly, I don't know but something to research.
In addition, I believe there would be more condensation in the side pipe thus making for more trouble with an upturned sensor to collect water condensation. A byproduct of combustion is water, lots of it. Most of it is vapor and goes out the exhaust pipe but as it hits the relatively cool side pipe and sensor water will condensate on the sensor especially if not heated. I'm not an expert and I'm just rambling on here but this gives you some things to research further.

The 'other' forum has changed and it is easier to search in some ways and harder in other ways. Still not happy with the change that recently took place over there. Use a google search instead of using any specific forum.

George

I just went to the link posted and Jeff Kleiner posted, with a picture, and he said the one he has installed have all worked fine.

[rich grsc]

I have seen them located down there a while back. Possibly predates this forum. Note that to work properly the sensor has to be hot, thus why they have heated sensors to aid in warm up running. The further away from the engine the cooler the sensor will be. Is it hot enough during normal running to work properly, I don't know but something to research.
In addition, I believe there would be more condensation in the side pipe thus making for more trouble with an upturned sensor to collect water condensation. A byproduct of combustion is water, lots of it. Most of it is vapor and goes out the exhaust pipe but as it hits the relatively cool side pipe and sensor water will condensate on the sensor especially if not heated. I'm not an expert and I'm just rambling on here but this gives you some things to research further.

The 'other' forum has changed and it is easier to search in some ways and harder in other ways. Still not happy with the change that recently took place over there. Use a google search instead of using any specific forum.

George

I just went to the link posted and Jeff Kleiner posted, with a picture, and he said the one he has installed have all worked fine.

Not trying to be a jerk, but have you ever laid you hand on the side pipe of a running car? If you get a serious burn from touching the pipe for just a half second, I can absolutely guarantee there is no moisture on the sensor.

[BB767]

Installing Holley Sniper EFI. Has anyone put an O2 sensor in the side pipe? I know this goes against having the sensor pointing down. If so, have you run into any problems? The other 2 options are reading only a single cylinder or buying new headers. New headers are not a player right now.
Thanks,
Doug

Hi Bobby,
I have a similar set up with the Sniper. Initially tried the sensor in a single pipe to simplify installation. It ran ok but just never felt quite right at lower RPMs. After recommendations from different tuners and exhaust people I was assured that moving it to the side pipe after the collector would not have an adverse effect on the Sniper tuning. I moved it last fall and it did in fact improve the smoothness of the engine at the lower RPM range. I too was concerned about the angle and operation that far from the engine, but the "experts" were correct. No adverse effects, no change to the other "good" characteristics of the Sniper tune. I am willing to chance the slight upward angle of the sensor to keep it out of sight, however if it ever becomes an issue, I have seen 45 and 90 degree elbows available for O2 sensors. One of these would allow you to mount the sensor at the "correct" angle with the drawback (in my opinion) that the sensor is now not in the direct flow of the exhaust gasses and would be much more visible, however I am told this would not be an issue either. My advice, go with it in the side pipe to start with and save yourself a change in the future.
Brien

The sensor supplied with the Sniper is heated, if it makes a difference, and you will need to purchase a longer lead, the supplied O2 wire harness is to short to reach the side pipe, at least mine was.

[Avalanche325]

There is an Engine Masters episode where they put a sensor in each header tube. It was shocking how much variation there was. A dual plane manifold was worse than a single plane. If you happen to pick the rich one, that could lead to running other cylinders dangerously lean.

If the manufacturer is good with the collector, I would do that. I have a sensor for carb tuning. It is angled up, but not like it is pointing straight up.

[phileas_fogg]

I have the Holley Terminator system, and put the sensor in the left side pipe. No issues since I installed it in May 2017.

I had to get an extension for the sensor, and routed the wire from behind the dash to the left side of the car, down the inside of the fiberglass forward of the door hinge, and then punched out through the body roughly even with the side pipe. I used one of the Finish Line rear quick jack grommets to protect the sensor cable.


John

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