no one will ever find this in that srv thread
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no one will ever find this in that srv thread
I agree, there is a ton useful information here also.Quote:
Originally Posted by LilSick
I feel like no matter what stoich is set to, on narrow band vehicles, it's going to trim to 14.7 with gas. I can and have been wrong many times. As I understand narrow bands run 0-1v, so changing stoich (my thought) is that it would basically change the ve calculation and my trims would be off. Tune ve and it's back at 14.7 target. Or in pe it would run richer than target (I target about 12.2 afr). So tune pe and it's all back where we started.
Maybe it's different with wideband cars.. I wonder if that's where the confusion comes from. Maybe I'm wrong. I am still learning.. But ultimately I'd like to know if changing stoich would actually change anything and benefit me any..
"It will still drive to the narrow-band voltage for stoich"???Quote:
Originally Posted by spoolboy
what is IT and what voltage is that?
thanks for the article
i saw one explaining lambda and the pump wide bands use i will find and post
still dont know what you mean by IT
or why 4 wire sensor that has 0-5v output is being called narrow band
I'm fairly certain the narrow band o2 sensor uses a 0-1v signal. I don't know which cars use a wideband but fairly certain trucks use narrow band.Quote:
Originally Posted by LilSick
Please correct me if I'm wrong but a narrow band will switch between above and below .5 volt to determine stoich.
I will look at a log in a second and see what the voltage reading is on my o2s to be sure
lets not talk about how a narrow band sensor works
that is in the article SB posted above
lets talk about what all is actually effected by changing the value in the tune (stoich)
Attachment 132483
*the 4 wire sensors in my scat are not narrow band
Attachment 132484
Attachment 132492
that log ^^^ is from my scat, not a hellcat (3.3v)
so... changing the value in the pcm... does it change the mixture at idle or not?
you had said the trims will be further off but that doesnt make sense
can you explain your theory?
you know i woulda already if my car were together right now
if its not changing the mixture OR what the sensors call good, what does that value do?
its a variable... what does it vary??
Changing stoichiometric in the tune affects airflow calculations. No different than changing fuel injector flow rate. Because of the way a narrowband functions, they will always try to maintain a physical stoichiometric ratio in closed loop no matter what fuel is used.
An example where changing stoichiometric is useful is going from regular gas to some blend of ethanol. E30 you'd set 12.96, and that way airflow wouldn't have to be re-tuned. All you have to do to understand this is look at a FlexFuel tune. There's a range of stoichiometric ratios on the fueling side but no range for airflow tables.
and the 392 uses 0-1v narrowband sensors?Quote:
Originally Posted by SiriusC1024
same thing
just calculations. none of it is real. i mean the engine is a pump, that is real. but think about ve
changing ve calculations changes fueling
cant change the actual airflow
Changing stoich will just skew the fuel trims during closed loop but the vehicle will always target lambda 1.0 using the narrowband O2 sensors.
However, once it's in open loop, then the stoich change will affect the actual lambda/AFR because it does not rely on O2 feedback here.
Im not sure what you mean,
but changing the stoich in the pcm does nothing at closed loop, because ANN will do this, as long as it is activated.
WB are only used by Hells.
can you make a narrow band car run on wideband?
not without changing the os and who knows what in the controller
maybe start a separate thread on the subject?
No. Why would you want to? The accuracy of a wideband decreases over time. Some Fords use widebands, but they are double checked for error with narrowbands through FAOSC.Quote:
Originally Posted by CHARLZ1FORD
If you want goofy non-stoich fueling full time then you'll have to run open loop.
if that is the case then why run it in the hellcat that has the same gpec2aQuote:
Originally Posted by SiriusC1024
im doing my best to post photos of the wiring but it insists on not uploading the photos but the only difference to the wiring is an extra 4 wires.
main reason i would like to run it is to make the car actually run the afr i commanded.
Right. Again, why would you want to run anything other than stoichiometric? Lean cruise maybe? Being able to tightly control fueling to maintain stoichiometric ratio is a big part of why modern engines have the efficiency and longevity they do. Might as well run a carburetor if that doesn't mean anything to you.
Using a wideband full-time, like in the Hellcat, gives the advantage of precise fueling during power enrichment. As far as PE, there are things called rich-best-torque and rich-best-power. The wideband is able to compensate for environmental conditions and fuel mixtures to maintain FAR during PE. This maximizes engine power and engine safety. With narrowbands the tuner sets PE, but it's simply open loop.
An old post I stumbled over.
As long as ANN has the control over stoich, there is a way to control it over a wideband.
I use this solution in older cars with Bosch injection.
Zeitronix uses a wideband with a controller wich converts it into a narrowband signal.
With a Software u can correct or fake the AFR as u want it to.
Maybe some want to test it, in my older cars it runs perfect.