Move O2 Sensors?
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Road Master
Joined: Sep 2013
Posts: 1,185
Likes: 248
From: Sterling IL.
Move O2 Sensors?
Has anyone moved their o2 sensors up near exhaust ports on stock decat head pipes with any suggestions if benifited anything? I have a new FP3 and it was said to be aware of cross talk causing problems with auto tune. I have a spare head pipe to do so any thoughts?
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
the older o2 sensors are located nearer the heads as they need the heat to activate- they don;t work below about 600şF.
the newer models ( 2010+) use a heated o2 sensor- which came in with the cat in the header for all versions
( yes, some 2009 models had cats, but they were higher up the header tube).
o2 sensors supply voltage in realtime to the ecm--- if you are running at 3000 rpms, the ecm is pulling data 750 times a minute from each of the o2 sensors and altering fuel delivery based on the voltage.
poor data may result from a poorly designed exhaust system which allows the pulses of exhaust gasses to moving back and forth within the exhaust tract, and/or exhaust gasses to eddy or even reverse course
( this can happen with a perf core baffle with the packing removed- or any exhaust tract in which the velocity drops, like if a 2" passage suddenly becomes 3" or larger)
so I would guess that if you have a well designed exhaust system which good controlled flow you would be running well- and moving the sensors wouldn;t do much
if your exhaust is a random put together with poor flow characteristics you may get an improvement moving the o2 sensors- It is possible that the heat produced closer to the exhaust will work against them.
but you'd likely get an even better result with a designed exhaust system with calculated flow and predictable results.
if you have smooth predictable motor operation at all throttle positions and transitions, I'd say you are doing fine
Mike
the newer models ( 2010+) use a heated o2 sensor- which came in with the cat in the header for all versions
( yes, some 2009 models had cats, but they were higher up the header tube).
o2 sensors supply voltage in realtime to the ecm--- if you are running at 3000 rpms, the ecm is pulling data 750 times a minute from each of the o2 sensors and altering fuel delivery based on the voltage.
poor data may result from a poorly designed exhaust system which allows the pulses of exhaust gasses to moving back and forth within the exhaust tract, and/or exhaust gasses to eddy or even reverse course
( this can happen with a perf core baffle with the packing removed- or any exhaust tract in which the velocity drops, like if a 2" passage suddenly becomes 3" or larger)
so I would guess that if you have a well designed exhaust system which good controlled flow you would be running well- and moving the sensors wouldn;t do much
if your exhaust is a random put together with poor flow characteristics you may get an improvement moving the o2 sensors- It is possible that the heat produced closer to the exhaust will work against them.
but you'd likely get an even better result with a designed exhaust system with calculated flow and predictable results.
if you have smooth predictable motor operation at all throttle positions and transitions, I'd say you are doing fine
Mike
Thread Starter
|
Road Master
Joined: Sep 2013
Posts: 1,185
Likes: 248
From: Sterling IL.
the older o2 sensors are located nearer the heads as they need the heat to activate- they don;t work below about 600şF.
the newer models ( 2010+) use a heated o2 sensor- which came in with the cat in the header for all versions
( yes, some 2009 models had cats, but they were higher up the header tube).
o2 sensors supply voltage in realtime to the ecm--- if you are running at 3000 rpms, the ecm is pulling data 750 times a minute from each of the o2 sensors and altering fuel delivery based on the voltage.
poor data may result from a poorly designed exhaust system which allows the pulses of exhaust gasses to moving back and forth within the exhaust tract, and/or exhaust gasses to eddy or even reverse course
( this can happen with a perf core baffle with the packing removed- or any exhaust tract in which the velocity drops, like if a 2" passage suddenly becomes 3" or larger)
so I would guess that if you have a well designed exhaust system which good controlled flow you would be running well- and moving the sensors wouldn;t do much
if your exhaust is a random put together with poor flow characteristics you may get an improvement moving the o2 sensors- It is possible that the heat produced closer to the exhaust will work against them.
but you'd likely get an even better result with a designed exhaust system with calculated flow and predictable results.
if you have smooth predictable motor operation at all throttle positions and transitions, I'd say you are doing fine
Mike
the newer models ( 2010+) use a heated o2 sensor- which came in with the cat in the header for all versions
( yes, some 2009 models had cats, but they were higher up the header tube).
o2 sensors supply voltage in realtime to the ecm--- if you are running at 3000 rpms, the ecm is pulling data 750 times a minute from each of the o2 sensors and altering fuel delivery based on the voltage.
poor data may result from a poorly designed exhaust system which allows the pulses of exhaust gasses to moving back and forth within the exhaust tract, and/or exhaust gasses to eddy or even reverse course
( this can happen with a perf core baffle with the packing removed- or any exhaust tract in which the velocity drops, like if a 2" passage suddenly becomes 3" or larger)
so I would guess that if you have a well designed exhaust system which good controlled flow you would be running well- and moving the sensors wouldn;t do much
if your exhaust is a random put together with poor flow characteristics you may get an improvement moving the o2 sensors- It is possible that the heat produced closer to the exhaust will work against them.
but you'd likely get an even better result with a designed exhaust system with calculated flow and predictable results.
if you have smooth predictable motor operation at all throttle positions and transitions, I'd say you are doing fine
Mike
I may just try an auto tune after running my canned map for some time to see how it works out. Im in play mode with a new toy.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
yes, it's maybe- it is all inter-related and tuning is being aware of how a change in exhaust flow can affect injector pulse width...and all that other stuff.
If you do this experiment, it would be neat to see your results
mike
If you do this experiment, it would be neat to see your results
mike
Thread Starter
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Road Master
Joined: Sep 2013
Posts: 1,185
Likes: 248
From: Sterling IL.
Well the FP3 with canned map of Twin Slash Rounds w Power Duals (recommended by V&H to be similar to Rush Big Louies with Decat header) is running nice so I may not change much at this time. It has solved my pinging on inclines and occasional decel pops. I will likely run auto tunes at some point but likely not til spring when can ring it out good. Maybe a winter project to prep another pipe and add some bungs farther up the pipe but not too close to the exhaust ports.
Seasoned HDF Member
Joined: Jan 2007
Posts: 20,616
Likes: 4,440
From: anacoco, la
just be aware that if you change the location of the o2 sensors, the existing cabling may not be long enough to reach. and with the new canbus systems, not sure how it would react if you just splice some wire in there.
Stage IV
Joined: Jun 2021
Posts: 4
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From: İSTANBUL
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Grand HDF Member
Joined: Sep 2013
Posts: 3,820
Likes: 588
From: Michigan
I think you are commenting on a 5 year old thread & your softail is a more complicated control system.
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