Stft/ltft
07-09-2015, 08:27 PM
#1
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Stft/ltft Got a street car and looking at the tune someone disabled both long and short term trims. So what's the advantage or disadvantage to disabling them on a cam only car?
07-09-2015, 09:06 PM
#2
depends on why they are disabled...
could have been a simple oversight... they turned them off to tune with a wideband, and when they were done, they forgot to turn closed loop back on....
could be a problem with an o2 sensor....or the exhaust has a leak before the o2 sensor
could have been as simple as they didnt know what they were doing and thought that open loop was the only way to make it work...
sometimes if you have a cam with a LOT of overlap, you have to put it in open loop at idle only to fight reversion issues and o2 sensors that cant tell it as false lean or rich reading.
or the o2's switch really slow at idle because they dont have enough heat in them..and people dont understand what to do to to make them work better at idle...
but if you can make it work right... its always better to enable closed loop with STFT and LTFT
could have been a simple oversight... they turned them off to tune with a wideband, and when they were done, they forgot to turn closed loop back on....
could be a problem with an o2 sensor....or the exhaust has a leak before the o2 sensor
could have been as simple as they didnt know what they were doing and thought that open loop was the only way to make it work...
sometimes if you have a cam with a LOT of overlap, you have to put it in open loop at idle only to fight reversion issues and o2 sensors that cant tell it as false lean or rich reading.
or the o2's switch really slow at idle because they dont have enough heat in them..and people dont understand what to do to to make them work better at idle...
but if you can make it work right... its always better to enable closed loop with STFT and LTFT