Journeyman
"And this one is just right" ~ Goldilocks
This is one I disagree with Claviger on. Referring again to the Triumph "adaptive fuel systems' pdf you can find on the tune ecu site, it says that the fueling will not be adjusted by the trims produced from the 02 sensor readings in areas of the map that are richer than 14.5:1. This is because the narrow band 02 can only sense whether the engine is above or below 14.5:1, but not how much. The computer then nudges the fuel up or down until it hits that magic number. If you look at the AFR map, only the low load/low throttle area is 14.5:1. Running the 02 sensor will allow the computer to adjust the fueling during cruising to maximize efficiency, but as soon as you roll the throttle open it ignores the 02 sensor and provides fuel based on the F table corrected for air density. Running the 02 allows it to compensate for a particularly humid day, or poor quality fuel for example. Be careful as running the 02 sensor disabled for long will kill it. It has to be heated to prevent water from condensating on it, or it will die. That is the reason for running a plug if you don't want to use it.
If you get the tune totally dialed in, removing the 02 sensor doesn't matter too much (basically like running a carburetor, the system always runs open loop), but for a canned tune I would leave it in. It will make sure that the AFR is at least right in the cruising and idling area where you spend most of your time, which is probably why you notice it running better. My '07 is running a canned tune with the 02 on, and has been for 5 years. It definitely is over rich when under heavy throttle, but it still idles nice and gets good mileage when cruising.
For what it's worth, I'm tuning my '18 with a wideband o2. Once I get the tune dialed in, I will go back to the factory narrow band 02 for the reasons I mentioned above. Also, I'm the first to admit [B]@Claviger[/B] has way more experience than me, this is just the way I read the info I can find. I really hope he comes back and jumps in here. Maybe if we all tag him enough it'll light up his inbox and get his attention lol.
Dude obviously knows his stuff.... I hope, at least, to continue seeing his updates about his ongoing projects.
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