Tuning MAF and VVE at the Same Time

[GHuggins]

Actually I may have sent it to you back in the day Bryan? Again memory isn't what it used to be - that's for damn sure.

I did find this, which sorta I guess has a few different ways in it - This was posted way back when - couldn't find the original post, but I know it was updated to refer back to Smoke's to average them together...

There are several ways to calculate (approximated = assuming some fixed ratio between IAT and ECT) GMVE.
These are the formulas I've been using with 2.24 version, but I haven't done the conversion to 3.x series variable names yet.

I took me a while to gather all the pieces from here and there (thanks Marcin for your work) to be able to update the GMVE table from almost any log with correct filtering.


Calculated GMVE (from Dynamic Airflow)

[PID.2320]/([SENS.70]/15*0.875*[SENS.30]/0.28705/(273.15+[SENS.11]))*875/0.28705

GM Volumetric Efficiency = Dynamic Airflow[g/s] / ( RPM[1/min]/15 * Displacement[l] * MAP[kPa] / 0.28705 / (273.15 + IAT[C]) ) * Displacement[cm3] / 0.28705


[PID.2320]*(273.15+[SENS.11])*1000*15/([SENS.70]*[SENS.30])

GM Volumetric Efficiency = Dynamic Airflow[g/s] * (273.15 + IAT[C]) * 1000 * 15 / ( RPM[1/min] * MAP[kPa] )



Calculated GMVE (from MAF)

[SENS.40]/([SENS.70]/15*0.875*[SENS.30]/0.28705/(273.15+[SENS.11]))*875/0.28705

GM Volumetric Efficiency = Mass Air Flow[g/s] / ( RPM[1/min]/15 * Displacement[l] * MAP[kPa] / 0.28705 / (273.15 + IAT[C]) ) * Displacement[cm3] / 0.28705


[SENS.40]*(273.15+[SENS.11])*1000*15/([SENS.70]*[SENS.30])

GM Volumetric Efficiency = Mass Air Flow[g/s] * (273.15 + IAT[C]) * 1000 * 15 / ( RPM[1/min] * MAP[kPa] )



Calculated GMVE (from cylAir which is derived from Dynamic Airflow)

[PID.2321]*(273.15+[SENS.11])*1000/[SENS.30]

GM Volumetric Efficiency = Cylinder Airmass[g] * (273.15 + IAT[C]) * 1000 / MAP[kPa]



Calculated GMVE (from WBo2)

([PID.6200]+[PID.6201])/2000*[PID.6210]*[AUX.20121]*(273.15+[SENS.11])*1000/[SENS.30]

GM Volumetric Efficiency = (InjectorPW_B1[ms] + InjectorPW_B2[ms]) / 2000 * InjectorFlowRate[g/s] * WideBandO2AFR * (273.15 + IAT[C]) * 1000 / MAP[kPa]


([PID.6200]+[PID.6201])/2000*[PID.6210]*[AUX.20122]*[PID.6001]*[PID.68]*(273.15+[SENS.11])*1000/[SENS.30]

GM Volumetric Efficiency = (InjectorPW_B1[ms] + InjectorPW_B2[ms]) / 2000 * InjectorFlowRate[g/s] * WideBandO2Lambda * CommandedAFRHiRes * CommandedEQRatio * (273.15 + IAT[C]) * 1000 / MAP[kPa]


([PID.6200]+[PID.6201])/2000*[PID.6210]*[AUX.20122]*[SENS.121]*[PID.68]*(273.15+[SENS.11])*1000/[SENS.30]

GM Volumetric Efficiency = (InjectorPW_B1[ms] + InjectorPW_B2[ms]) / 2000 * InjectorFlowRate[g/s] * WideBandO2Lambda * CommandedAFR * CommandedEQRatio * (273.15 + IAT[C]) * 1000 / MAP[kPa]


Depending on the mode (OL or CL, SD, Hybrid or MAF only) it is necessary to choose the best suited calculation method. Generally cylAir gives the best quality but I have used alsThe math:
GMVE STFT % error = ((MAF_af)*(1+(STFT_avg)/100)-(GMVE_af))/(GMVE_af)*100

(([16.71]*(1+(.01*[6.156]+.01*[8.156])/2)-[12.56]/60*4*[11.92]*[2312]/[2127.240])/([12.56]/60*4*[11.92]*[2312]/[2127.240]))*100


https://forum.hptuners.com/showthrea...ation-for-gen4o an average of all four.

[GHuggins]

I believe i have that formula that you're after, or lost.

If I sent it to you Bryan - post it up

[Area47]

What up dude!



If it is your exhaust formula I don't have the PID it needs.

Thought id jump in to the festivities.

[Area47]

If I sent it to you Bryan - post it up

I'll have to check it when I get home.

[PGA2B]

Here is my current VVE Histo
.
VVE.2.png

I know I have more work to do.

[Area47]

Yep, that is the one I found that you gave me.

Except I don't have 5011 Exhaust Valve Start Rumble Active or PID 273

Something isn't right with that one. The only real time i mess with ve anymore is on my 05 1500. The toy has a holley on it.

[bfg4wd]

I am starting to adjust the fueling on my genIV E38 ECU using this method. In my first log attached, the MAF is lean as I expected but the VVE is rich. Using the maths for VVE_CL, and MAF_CL. I did not apply the filters but still expected both to be lean. Before any changes are made I will use the filters, this was a short trip around the block.

Any help is appreciated.

[Cringer]

I am starting to adjust the fueling on my genIV E38 ECU using this method. In my first log attached, the MAF is lean as I expected but the VVE is rich. Using the maths for VVE_CL, and MAF_CL. I did not apply the filters but still expected both to be lean. Before any changes are made I will use the filters, this was a short trip around the block.

Any help is appreciated.

I would be looking to address the bank to bank mismatch first. The passenger side is really lean...any chance you have an intake manifold gasket leak or exhaust leak?

[bfg4wd]

I would be looking to address the bank to bank mismatch first. The passenger side is really lean...any chance you have an intake manifold gasket leak or exhaust leak?

Yes, I did see that was hoping to get fueling closer first, in case I need to drive to exhaust shop again.

Thanks I will look into that first.

[sgod1100]

I am starting to adjust the fueling on my genIV E38 ECU using this method. In my first log attached, the MAF is lean as I expected but the VVE is rich. Using the maths for VVE_CL, and MAF_CL. I did not apply the filters but still expected both to be lean. Before any changes are made I will use the filters, this was a short trip around the block.

Any help is appreciated.

if you drove just around the block odds are those numbers aren't going to be that accurate. Need to drive much longer than that

[Capt Chewy]

Still here lurking...

My thoughts on this is that, Not just smokeshow but others have said and showed that the original code is written off of the maf error. If that is how its written (GMVE) then it only seems logical to tune it that way unless you do an OS upgrade to sd. Not saying do them both at the same time if thats not working, but using gmve.

But i'm not a tuner, trying to learn to tune from y'all so...

[[email protected]]

You don?t need to measure exhaust flow or anything. Your known good injector data (*cough cough* OEM or Injector Dyanmics) is your flow meter, and your wideband tells you how much air you?re getting.


I make a living off of doing things better than other people, so I?m not going to share what shaves hours off my cal times. It was more of a note that maybe you (meaning everyone) should consider a very different approach.

And also not dismiss Jake? who is, well, not wrong when he tells you something.

i struggle a lot with tuning, and I may never get it right. But I'd never let anyone discourage me with statements such as yours DS. I could only hope you are poking fun at Cringer? If not, then I'd simply just throw two up at you.

I'm from old school timing light and marks along with distributor. I will say, the effort alone put out from Cringer seems.....noteworthy, not to mention, I feel, is how YOU, DSteck probably were at one point in time i would guess when you FIRST started?

Here, let me answer for you. YUP. IMO, now its just my opinion...but i feel the quoted statements in my post....are by far the most pompus statements ive ever read here on the forums.

Arent forums....ones like this....all about HELP? My point is, Im sure Cringer put a lot of work and time into something he believes in. Take your 1 + 1 to your grave DS. itll do you a lot of good there im sure of it. back to my point and bottom line.....

Any child, kid, or whoever...in life, who makes an effort in trying to even riding a bike and does it successfully....isnt any better or worse than the one next to him or her, that tries just as hard and doesnt do it successfuly. Or am I wrong here? the one who doesnt try, or doesnt teach, or doesnt learn.....is the idiot. NO? Yes?

all i know is, knowledge is power. why would any fool not want to share it, improve it, know it, try it, be it, see it, all the above? math magician or not, DS is an idiot from where i come from. i may not be smart, but im sure im ten times the man driving a chevette...probably get better PXSSX too, and more of it just cuz im not an a hole? im sure of that too.

Cringer, keep working...its all that matters to be successful. quitters are shitters remember that.

[morepowerjoe]

Is the filter formulas you have in the graph on the video for the maf closed loop accurate. Or where can I find the filter formulas?
Thanks

[GHuggins]

Toward the end of the what is dynamic airflow thread. New formulas in there too that have had the equations corrected and cleaned up for ease of use too.

[morepowerjoe]

Thank you sir.

[SiriusC1024]

Toward the end of the what is dynamic airflow thread. New formulas in there too that have had the equations corrected and cleaned up for ease of use too.

https://forum.hptuners.com/showthrea...-airflow/page8

[morepowerjoe]

Thank you Sirius

[Hoosier Tuner]

My tuning method for the past nearly 20 years hasn't been nearly as math and algorithm driven as the approach you all seem to be taking or maybe I'm missing the point of all of this thread.

I plot Dynamic Air with MAF Air on the Chart vs Time. Areas where they are on top of each other, MAF is clearly driving the fueling at that point and make corrections to the MAF calibration to bring the fuel trims in line. Areas where they don't line up and in relatively steady state where I would normally expect them to be in line there is too much of a disconnect between VE and MAF such that the PCM has abandoned the MAF - in those areas I make VE corrections to bring the fuel trims in line, and many times in doing so will get the MAF and DA lines to match up. If they don't and fuel trims there are where I want will then make MAF cal correction to get it in line. Lastly I look at the transient areas - in those areas I expect the MAF and DA lines to not be on top of each other (there's a reason GM is using both because they didn't expect the MAF air to be correct there). In these areas I look at what the O2s are showing - if they seem to be switching normally all is good - if too lean I increase VE table values in that area - if too rich I decrease.

As noted above this is my approach. It may not be as "elegant" as what you all are working on, and may not work well for remote tuning as it takes a fair amount of log, tweak tune and repeat to dial in.

[GHuggins]

My tuning method for the past nearly 20 years hasn't been nearly as math and algorithm driven as the approach you all seem to be taking or maybe I'm missing the point of all of this thread.

I plot Dynamic Air with MAF Air on the Chart vs Time. Areas where they are on top of each other, MAF is clearly driving the fueling at that point and make corrections to the MAF calibration to bring the fuel trims in line. Areas where they don't line up and in relatively steady state where I would normally expect them to be in line there is too much of a disconnect between VE and MAF such that the PCM has abandoned the MAF - in those areas I make VE corrections to bring the fuel trims in line, and many times in doing so will get the MAF and DA lines to match up. If they don't and fuel trims there are where I want will then make MAF cal correction to get it in line. Lastly I look at the transient areas - in those areas I expect the MAF and DA lines to not be on top of each other (there's a reason GM is using both because they didn't expect the MAF air to be correct there). In these areas I look at what the O2s are showing - if they seem to be switching normally all is good - if too lean I increase VE table values in that area - if too rich I decrease.

As noted above this is my approach. It may not be as "elegant" as what you all are working on, and may not work well for remote tuning as it takes a fair amount of log, tweak tune and repeat to dial in.

I've usually got way too much going on to do something like that - because of how some of these tunes are setup it can take an hour with regular log corrections to get a tune ready to send back out with updates so it would take considerably longer to hand pick the tables like that. Dynamic always controls fuel. It's just whether or not there are other things such as transients playing into it. I will say with the updated maths and updated airflow transient filter thanks to Sirius, that you should be able to fully dial the VE table in, with 3 honest good passes tops. Then you can fine tune if you like while finishing up the MAF. I've been impressed with it so far. I've found my cylinder airmass calcs off as much as 30some percent in places. It's always been spot on in the lower rpm areas funny enough, but once the rpms start going up the dynamic calculation is far more accurate once compared with failing the MAF and double checking.

[SiriusC1024]

My tuning method for the past nearly 20 years hasn't been nearly as math and algorithm driven as the approach you all seem to be taking or maybe I'm missing the point of all of this thread.

I plot Dynamic Air with MAF Air on the Chart vs Time. Areas where they are on top of each other, MAF is clearly driving the fueling at that point and make corrections to the MAF calibration to bring the fuel trims in line. Areas where they don't line up and in relatively steady state where I would normally expect them to be in line there is too much of a disconnect between VE and MAF such that the PCM has abandoned the MAF - in those areas I make VE corrections to bring the fuel trims in line, and many times in doing so will get the MAF and DA lines to match up. If they don't and fuel trims there are where I want will then make MAF cal correction to get it in line. Lastly I look at the transient areas - in those areas I expect the MAF and DA lines to not be on top of each other (there's a reason GM is using both because they didn't expect the MAF air to be correct there). In these areas I look at what the O2s are showing - if they seem to be switching normally all is good - if too lean I increase VE table values in that area - if too rich I decrease.

As noted above this is my approach. It may not be as "elegant" as what you all are working on, and may not work well for remote tuning as it takes a fair amount of log, tweak tune and repeat to dial in.

You're on the right track. What we've been working on accelerates the process.