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Discussion Starter #1
I have not had the chance to add a wide band bung yet and have built a histogram for pt and wot afr, to see if I can see afr. I built a user defined math to calculate afr and scaled it with rpm and aircharge , just curious if anyone had built a similar histo and compared it to a wide band
 

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I've been trying to get my AFR ratio to read correctly in HPT for a while now. I can't see to get it to read the same as my gauge. It is off by at least 4 numbers. At startup my gauge reads 14.5-7 and in HPT I'm seeing 10.5-7. I used the predefined PLX setting which I thought should work, but to no avail. I'm going to finally try to nail this deal down after the MSHS event here at MIR. I need to get all of my tools working correctly.
 

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Hey dak, here is how I set up my histo and maths. Have no idea how close it is lol. Would love someone to test it and compare to a wide band
Tried to filter it to remove transients etc but that failed lol
 

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If you aren't using a wideband, the results won't be accurate, regardless if the software is setup correctly. Garbage in, garbage out.
 

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If you aren't using a wideband, the results won't be accurate, regardless if the software is setup correctly. Garbage in, garbage out.

WHy do you say that. My wide band has been very good in fine tuning my tune. It just sucks having to look at the gauge and reference it with the tune. I'd like to get the graphs all on the same area, if that makes sense.
 

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Hey dak, here is how I set up my histo and maths. Have no idea how close it is lol. Would love someone to test it and compare to a wide band
Tried to filter it to remove transients etc but that failed lol



Hopefully after the MSHS event here in MD this weekend, I can get on this. I'd like to iron out my AFR reading issues. This way I can more efficiently tune
 

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I can attempt to duplicate what you have done this weekend. After the MSHS event. I'd like to iron out what the hell my MVI is doing with respect to the AFR's.... This could be a win win for both of us.
 

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I think you are correct with respect to the voltage deal. I know for sure the pinning is correct. I may have to look into the settings that came with the PLX device. Thanks for sharing your thoughts
 

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Yeah using the factory narrowband is not the way to do it. For PT tuning with no wideband you use fuel trims, which rely on O2 readings, factory sensor is only accurate near stoich otherwise the just indicate rich or lean. At WOT the factory O2 and fuel trims (short term goes to zero and long term locks to previous value just before pedal voltage hits your set WOT voltage) are essentially useless.

FYI here is an excellent write-up from HP tuners forum on how to set-up AFR or Lambda error (again it assumes you have a wideband installed).
https://forum.hptuners.com/showthre...R-Graphs-vs-VE-Table-(non-Virtual-VE-Vehicles)
 

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As always thanks for the link. This place is a great resource for sure.
 

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Discussion Starter #12
Lando,, trust me I know the wide band is the way to go , I was just curious if anyone had tried this, inquiring minds need to know. This was simply an experiment I ran and asked the forum for knowledge and learning
 

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Lando,, trust me I know the wide band is the way to go , I was just curious if anyone had tried this, inquiring minds need to know. This was simply an experiment I ran and asked the forum for knowledge and learning
I don't think it will be useful (although I never really tried myself) as the NB will only indicate if you are rich or lean. It will be difficult to tell how rich or lean you are. For example, if you see 800mv on the o2 it could be that you are 14:1 or 10:1...not terribly useful for optimizing WOT fueling. Kinda like using an optical switch to tell you how bright or dim room lighting is when all it can tell you is the lights are on or off.
 

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Discussion Starter #14
Thanks chalky, I’m not trying to look at NB, set up my experiment with user defined math dividing air mas by fuel mass,, it APPEARS to follow what is commanded by the tune really well at WOT, and varies from my commanded stoic at PT +- .7 as I haven’t figured out how to filter out changes in pedal / throttle while normal cruising
 

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Thanks chalky, I’m not trying to look at NB, set up my experiment with user defined math dividing air mas by fuel mass,, it APPEARS to follow what is commanded by the tune really well at WOT, and varies from my commanded stoic at PT +- .7 as I haven’t figured out how to filter out changes in pedal / throttle while normal cruising

My bad.

So you are logging AFR using Math (Air mass/Fuel mass)...and then you are logging commanded AFR and comparing the error between the two?

And then you want to compare it to the error between measured wideband AFR vs commanded AFR and see which method yields the least error?

Is my understanding correct?
 

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Discussion Starter #16
Yes to logging using maths, then comparing to commanded, I have not gotten a wide band bung installed ,,, yet
 

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Yes to logging using maths, then comparing to commanded, I have not gotten a wide band bung installed ,,, yet
Using your AFR math (air mass/fuel mass) is not going to let you circumvent using a WB for tuning at WOT. The air mass is derived from MAP measurements but the fuel mass is derived from a PE table (in conjunction with injector fuel mass/pulse tables) which specifies adders to stoich to achieve a desired AFR based on air charge and rpms (again, the factory O2 have no input to WOT fueling). Basically you are just confirming the PCM is commanding the AFR prescribed by the PE table but you have no feedback as to whether this is the correct fuel charge for that point of operation/engine load. Now if you had a WB installed and you notice the WOT commanded AFR is off then that suggests you need to add/remove fuel.

Here are some thread that give insight to the PE table.

http://www.challengertalk.com/forums/6397546-post17.html (you are better off using this method until you get your WB installed)
https://forum.hptuners.com/showthre...uel-Mass-spark-advance&highlight=dodge+stoich
https://forum.hptuners.com/showthread.php?36964-Dodge-Tuning-Hints-and-Tips&highlight=dodge+stoich
https://forum.hptuners.com/showthre...ning-Options-and-Steps&highlight=dodge+stoich
 

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Discussion Starter #18
Great info and explanation chally!! Thanks for the insights, this experiment was never meant to tune via histo instead of widebsnd just to see what we info we can get through hpt.
 
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