I have a 2009 street glide with the 18mm O2 sensors. I have Fabricated my own exhaust. I would like to finish it tomorrow. I just need to weld up the O2 Sensor bungs. i need to know how far from the head should the O2 sensor be. Because of the design of the exhaust it will be hard to get them more than 4" from the head. I know they need to have a 10* angle going with the flow of exhaust but what is the minimum and maximum distance.

Thanks
John

 

I would like to know the answer your question myself. It is very hard to get an answer on this topic.

 

You want them close to the head - 4" is ideal - you can go to 6 maybe 8 if you need to - Eastcoast Jim

 

Actually the small sensors are heated and are designed to be able to be further down the pipe. Too close to the head can cause the sensor to be exposed to too much heat. The other side of the equation is understanding that the HD ecm looks at the sensor read at only certain moments in time (crankshaft rotation due to cam events )so the location can be tied to the distance down the pipe. If you're in the ballpark of where an OE sensor would be for the same style system you're most likely all good. You will also be ok in other locations, but that is the safest answer if you are doing this yourself.
The other thing to know is that if there is a part where the system comes together, the sensors must be far enough up the pipe so they do not cross-read. When that occurs, the ecm can't control fuel properly and there are a host of driveability issues.

 

I found a couple photos online of placements for those 02 bungs thank you for the person who actually took the photos.