This thread is dedicated to the discussion of the correct method of tuning airflow models. It is a continuance of talking points compiled from various threads.
https://forum.hptuners.com/showthrea...Caused-by-What
https://forum.hptuners.com/showthrea...6864-VE-Tuning
Last edited by SiriusC1024; 12-19-2023 at 04:11 AM.
Here's a great example of what I'm talking about with the discrepancy between CL/NB and WB at low exhaust flow and temps. Fuel trims are pulling fuel, but the WB is saying it's lean here.
NB 1.png
WB 1.png
You'll notice that up higher (WOT) things start to agree, and that's a good indication that the wideband is an accurate data source here.
NB 2.png
WB 2.png
Widebands aren't accurate indicators for part throttle and idle tuning. It's not simply an offset problem with the wideband that can be calibrated away. If it was then we'd see the same magnitude difference throughout the range. It's not linear at all.
Logically, this is admitting widebands may be inaccurate, and that tuning with narrowbands will yield correct results.Originally Posted by kingtal0n
Last edited by SiriusC1024; 12-19-2023 at 05:22 AM.
Again, the discrepancy isn’t a linear relationship. It’s not an offset. The reason for the difference between the two is the control algorithm working behind the scenes.
This contradicts your previous statement about voltage references. Having the wideband telemetry sent over CANBUS has no bearing on accuracy. The power and ground supply to the wideband sensor will be the same as a non-CAN model. All that's being done is the analog signal is converted to digital - measurement error included.
CAN WB.png
Last edited by SiriusC1024; 12-19-2023 at 05:23 AM.
Never wrestle with a pig.
It's not only a matter of the sensor. It's the sensor combined with the control method. That's the closed loop part.
Take a look at a Ford file for a vehicle that uses widebands. It's not as basic as poll sensor-create average like with VCM Scanner. FAOSC is pretty neat. It automatically trims the wideband for sensor drift. As you can see there's quite a bit going on with the control side.
Ford WB control.png
The point is that, in modern implementations, a narrowband is used as a point of reference to correct the wideband. Moreover, the narrowband is used as a reference point for the control algorithms that are based on wideband feedback.
The flaw in relying on direct wideband sensor feedback is recognized by auto manufacturers. Hopefully, it's now clear to the readers. Stick with the factory control method. In Gen 3 that means CL tuning with the narrowbands.
To me the difference comes to down to philosophies. Intrusive versus non-intrusive or least intrusive. It really is as simple as that.
This guy is an idiot. Anyone that comes up with a calibration like this is a complete idiot. It is laughable.
uploadmetryboilingtime9-22-23.hpt
Just wow!.jpg
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And he is worried about someone posting a formula without writing a book to explain it, but no explanation about how that tune is completely different from how everyone else does it. And probably tweaked so that it only works on one particular vehicle. If it does that.
The shape of the VE is all you need to know, to know he doesn't know.
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Been looking for that tune. I'd like to see what would happen if that was redone CL. I guarantee the "spark plug cleaning mode" is actually stoichiometric while the wideband is reading lean.
One thing you can guarantee is the shape of the VE would be completely different. It is nonsensical. No engine has the same VE across the entire RPM band at a specific Kpa. Yet Cpt. Klingon will tell you that's super secret method.
The guy is a hack. He promotes, endorses, encourages hack tuning. He is everything that's wrong with the aftermarket tuning industry.
Last edited by edcmat-l1; 12-19-2023 at 12:38 PM.
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That link you (panic) double-posted shows how to create a formula logging EGR through wideband:
Volts/ [(0~Max Voltage)/(max AFR - Min AFR)] + [min AFR +any offsets in AFR values]
This is the formula I used:
([2811.10]/(4/7))+10
autometer setup.png
Mine and the link are the same thing, yet:
Your comment originated because you thought I was modifying the offset with a multiplier. That was wrong. You jumped to conclusions instead of getting the background info. Go read the datasheet.
Ok, bro. Looks like I know both how to use a wideband and when not to use it.
Last edited by SiriusC1024; 12-19-2023 at 09:53 PM.
This thread seems like it's a specific person bashing thread and not a duscussion about O2's and I'm not here for that, but to instead say what I've said for the last decade on the subject. O2 settings can be changed to bring the O2's and wideband closer together. Gen 3's had more ability to do this with certain cals than the gen 4's did. There are also a lot more settings in the GM calibration specifically for O2 positioning than we are given too. Honestly the ones we're given are just the skin of the teeth settings. Here is a screenshot for both gas and alcohol changes right out of a GM cal --- Post O2's even have their own position settings for redundancy pre cat O2 and cat checks... I had some post O2's kicking my arse on a gen V and reached out which is how I found out about those...
O2 Distance settings.jpg
Now with that being said will the O2's and wideband perfectly agree with one another. Well no, not in all cases but they can be brought in closer to one another. We have to keep one thing in mind with widebands. Widebands will show current real time readings downstream of the combustion event where as the O2's will skew based on location settings. Once we slow down the exhaust stream via long tubes or from pump losses such as a cam O2's are skewed just because of their location settings. By bringing them closer together we put things back more in line both countering the post combustion event and further downstream variables for both the O2's and wideband. The bigger the cam or whatever especially combined with headers and a bigger cai makes this that much harder to do. As for King, I've watched some of his vids where he shows his wideband readout and it does stay within a couple percent of 14.7 most all times, but he's running in open loop and there are several open loop multipliers to use to counter skew the airflow models. Would be interesting to see a vid of just the wideband while driving to see just how out things get cause usually when in open loop this is where things get harder to control....
Personally I get them closer then use trims - as that's what the ecm will use - to dial in everything outside of wot. You'll also find that by making them read closer your MAF curves will be a lot smoother going into PE. I'm sure we've all seen the airflow models where they had that one big hump going into and staying in PE?
Last edited by GHuggins; 12-19-2023 at 10:48 PM.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
It's not so much about bashing him as it is keeping his diversionary comments off people's posts. If he wants to talk about OL tuning he can come here. If you follow the links (and you can see it in some of the snippets here) you'll notice it's frequently him doing the bashing, name calling, and condescending. kingtal0n brings up common arguments as to why tuning OL is ok, so using him as a sounding board will help others better understand the ways it can go wrong.
You bring up a good point about transport delay. What is your method for addressing this?
I don't have a great method for it. Transport or integrator delay is supposed to be the distance although it's not entirely but in fact is a small piece, so it needs to be increased especially at your lower airflow readings. Proportional is your fuel required to be added to or taken away from for switching. I normally lower that to help with "O2 bucking". Depending on the gen there are other settings that contribute to this such as the closed loop setting on gen 4's that has nothing to do with actual open and closed loop in regards to entering but rather it controls how much fuel is added to or taken away from once entering complete closed loop. In other words they use stft's combined with O2 switching to stabilize and light off the cats only the switching is done at lower intensity, so I change the temperature setting for it to stay at this lower intensity. That is gen 4's only. Since fueling is injected straight into the cylinder you can actually really kill fuel switching on gen V's. I've gone to .0whatever settings for the limit tables. You just have to watch out cause for the majority of platforms out there settings below 1.2 in that table can lead to O2 and fuel drift. For select gen 3's you have idle specific proportional tables making them a lot easier to correct for idle specifically.
Verlon would probably be the best to talk to about how the O2's are "programmed". Otherwise I posted something in regards to gen 3's about 7 or 8 years ago if you can find it when I was experimenting on them then.
Last edited by GHuggins; 12-19-2023 at 11:57 PM.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
You have peaked my interest. Would like to know more about it too. I have always wanted to "figure out" transport delay and if there is a generic formula like you would have on a MAF tube change. You know if you have primaries X inches long and the O2's are Y inches after the collector the time/adder/multiplier is changed by Z percent +/- a given amount based on Cam profile. Having nothing more than a basic explanation as you mouse hover over a setting doesn't really ever give a good explanation as to why a value should be changed/unchanged and its effect on the system as a whole. So much seems to always be change this or that and see what it does.
I think anyone who spreads the BS that guy does so condescendingly needs to be bashed over the head repeatedly. Especially when they're a complete hack and come on now, the guy is a complete hack. It would be different if his own personal tune file was some sort of open loop majikal toonery. Tip toeing around the guy, avoiding him and letting him post his crap is not good for the community in general.
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Indeed. Greg, how do you even recognize that there is a problem. Sure, it's easy to tell if the nb/wb don't match up. As far as O2 settings, as long as the O2's are switching full sweep with regular frequency then they're good to go.
https://forum.hptuners.com/showthrea...LTFT-histogram
What am I missing?
If you change the pumping of the engine or even how it measures airflow - for instance something as simple as a cai being installed that changed the tube diameter then all of those airflow corrections change. Now take something like that and combine it with long big diameter exhaust tubes or a custom intake that completely relocates the MAF. This is why you see O2's start switching in the mid 15's afr wise or worse and why you wind up with O2 oscillation induced engine surge with low rpm, low airflow cruise scenarios. Wideband error near 0 and the O2 switching at stoic is the main way I use to dial them in. For instance, in those above shown pics, I can change the third and forth columns in trucks with long tubes and cams and gain low end torque by doing nothing other than changing the O2 position in the calibration closer to their new locations to better control the fuel in the combustion chamber. Now even with all of this being said, I'm not going to tune one in open loop just for the simple reason that all the multipliers are being ignored at this point. I think it's purely archaic and a complete waste of time to do it that way, but that's how everyone was taught years ago. It's no different than failing MAF's to dial in the VE on newer platforms this day and time. Again, you still have to on gen 3's, but nonetheless.... Another BIG benefit to taming the O2's down and getting them more in line is how quick and easily you can dial in the fuel models. I've had them with what I thought was decent switching only to have fuel trims changing 5 to 8 % each time the car was driven. Tamed the O2 switching down some more and all of a sudden 3 % swings. There's a lot of engine control in the O2's and why it's important to calibrate them. Why do you tune a MAF or VE table? It's no different. It's worth anybodies time to dial them in if nothing else just a little better than what they are. Saves time and keeps things in control.
This is a 17 silverado - cam, lt headers, cai - this is what I'm talking about... A lot of "tuners" out there won't bother to dial this stuff in and tune thousands of cars. Does that make the way they do it right? Or how the OE does it dialing in the O2's locations? You can see with bank 1's O2 making it's fuel correction that the EQ error is near 0.
O2 control.jpg
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
So, you're not ignoring the wideband in areas where it disagrees with the narrowband fuel trims, and you're not compensating the wideband with math.
When you make an adjustment to the narrowbands does the wideband report change as well? Do you know you're good when the two converge or something? With that there's no point of reference, unless what you're saying is the wideband is what's constant and you make narrowband fuel trims match it.
Seeing a log like in post #2 what would be your thoughts on what's going on?
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