Quick guide to simultaneous VVE/MAF calibration for gen4+

[sgod1100]

Part 2 coming soon...

anxiously waiting...lol

[amiller3831]

Please don't shun, If im understanding correctly, i build these math parameters under the user math manager in the scanner? And graph as normal.

[radz28]

Yup. It seems to work pretty well for me.

[Ghostnotes]

anxiously waiting...lol

ditto

[smokeshow]

anxiously waiting...lol

ditto

Lol. So, my initial idea for a part two was to address an issue that compromised the results of this procedure....MAF reversion. If you're not familiar, this is a phenomenon that occurs (usually) with aftermarket intake tubes. Reversion is exactly what it sounds like - reversal of flow. When you add a camshaft that has a late IVC angle and/or pair it up with a new intake tube (or if you are bone stock, in the case of the LS2 GTO), often times what you've done is create an environment for 'pneumatic communication' of the camshaft with the MAF sensor. The big cam closes the intake valve late, and at low RPM pushes some charge back out of the cylinder before the valve closes. This causes a pressure rise in the intake and the reversal of flow. The flow reversal can result in high OR low measured mass airflow relative to actual mass flow, depending on the hardware itself. The problem then became, how do I use sensor measurement as a reference for correction to an airflow model when the sensor may unpredictably yield inaccurate results? It is easy enough to pick the error out of a graph with your eyes, but not so easy within a set of collected data, and definitely not possible with HP Tuners due to the slow data collection rate and limitations of the scanner itself. I used to calibrate with a tool called Inca which was capable of data collection as fast as the controller execution loops updated the variables...but that doesn't happen on CAN that HPT uses. The data comes in scheduled and slow and doesn't provide a signal I can use that allows me to separate the error from it. Haven't figured out a way around that yet and not sure if I will. At least not without scripting in MATLAB, which few have access to.

That said, I've gotten requests a few times for a procedure on data filtering. Not really a 'part 2', but is still relevant and can help eliminate some error that you may find when calibrating with this procedure. Is there any interest for a 'how to' on data filtering?

[cadillactech]

Lol. So, my initial idea for a part two was to address an issue that compromised the results of this procedure....MAF reversion. If you're not familiar, this is a phenomenon that occurs (usually) with aftermarket intake tubes. Reversion is exactly what it sounds like - reversal of flow. When you add a camshaft that has a late IVC angle and/or pair it up with a new intake tube (or if you are bone stock, in the case of the LS2 GTO), often times what you've done is create an environment for 'pneumatic communication' of the camshaft with the MAF sensor. The big cam closes the intake valve late, and at low RPM pushes some charge back out of the cylinder before the valve closes. This causes a pressure rise in the intake and the reversal of flow. The flow reversal can result in high OR low measured mass airflow relative to actual mass flow, depending on the hardware itself. The problem then became, how do I use sensor measurement as a reference for correction to an airflow model when the sensor may unpredictably yield inaccurate results? It is easy enough to pick the error out of a graph with your eyes, but not so easy within a set of collected data, and definitely not possible with HP Tuners due to the slow data collection rate and limitations of the scanner itself. I used to calibrate with a tool called Inca which was capable of data collection as fast as the controller execution loops updated the variables...but that doesn't happen on CAN that HPT uses. The data comes in scheduled and slow and doesn't provide a signal I can use that allows me to separate the error from it. Haven't figured out a way around that yet and not sure if I will. At least not without scripting in MATLAB, which few have access to.

That said, I've gotten requests a few times for a procedure on data filtering. Not really a 'part 2', but is still relevant and can help eliminate some error that you may find when calibrating with this procedure. Is there any interest for a 'how to' on data filtering?

Jealous you got to work/play with Inca. I have seen it inaction but never got to use it myself. Pretty amazing.

I am sure some data filtering guides would help out a lot of people on their quest to nail airflow calibration down. I have always tried to keep things steady state on a dyno or just lived with the slow HP Tuners data and filtered out the obvious transients but would love to see what your approach is without using MATLAB or another data collection program.

Keep up the good work!

[PGA2B]

I'd like to see what kind of filtering you do. If nothing else to validate my own filters I use to try to eliminate trash data.

[ttz06vette]

Lol. So, my initial idea for a part two was to address an issue that compromised the results of this procedure....MAF reversion. If you're not familiar, this is a phenomenon that occurs (usually) with aftermarket intake tubes. Reversion is exactly what it sounds like - reversal of flow. When you add a camshaft that has a late IVC angle and/or pair it up with a new intake tube (or if you are bone stock, in the case of the LS2 GTO), often times what you've done is create an environment for 'pneumatic communication' of the camshaft with the MAF sensor. The big cam closes the intake valve late, and at low RPM pushes some charge back out of the cylinder before the valve closes. This causes a pressure rise in the intake and the reversal of flow. The flow reversal can result in high OR low measured mass airflow relative to actual mass flow, depending on the hardware itself. The problem then became, how do I use sensor measurement as a reference for correction to an airflow model when the sensor may unpredictably yield inaccurate results? It is easy enough to pick the error out of a graph with your eyes, but not so easy within a set of collected data, and definitely not possible with HP Tuners due to the slow data collection rate and limitations of the scanner itself. I used to calibrate with a tool called Inca which was capable of data collection as fast as the controller execution loops updated the variables...but that doesn't happen on CAN that HPT uses. The data comes in scheduled and slow and doesn't provide a signal I can use that allows me to separate the error from it. Haven't figured out a way around that yet and not sure if I will. At least not without scripting in MATLAB, which few have access to.

That said, I've gotten requests a few times for a procedure on data filtering. Not really a 'part 2', but is still relevant and can help eliminate some error that you may find when calibrating with this procedure. Is there any interest for a 'how to' on data filtering?

Certainly a problem I have experienced with the intercooler design I have. Stock LS7 MAF could not handle the uneven pulses. Went to a Colorado MAF and it improved somewhat, but still a lot of bucking down low. Ended up with an Abaco MAF where I could load a profile directly into the MAF to smooth out the high points and low points. That coupled with YOUR VVE filtering and some cell specific timing reduction in effected low fueling/low RPM areas eliminated almost all of the symptoms. I also raised my MAF kick in point understanding it is always present when active. Unfortunately Abaco went out of business.

https://www.jegs.com/InstallationIns...39/039-MAF.pdf

[radz28]

I'd like to see what kind of filtering you do. If nothing else to validate my own filters I use to try to eliminate trash data.

+1!!! please.

[Pitbull]

+1 on continuing education about this

[00DAKDAK]

Lol. So, my initial idea for a part two was to address an issue that compromised the results of this procedure....MAF reversion. If you're not familiar, this is a phenomenon that occurs (usually) with aftermarket intake tubes. Reversion is exactly what it sounds like - reversal of flow. When you add a camshaft that has a late IVC angle and/or pair it up with a new intake tube (or if you are bone stock, in the case of the LS2 GTO), often times what you've done is create an environment for 'pneumatic communication' of the camshaft with the MAF sensor. The big cam closes the intake valve late, and at low RPM pushes some charge back out of the cylinder before the valve closes. This causes a pressure rise in the intake and the reversal of flow. The flow reversal can result in high OR low measured mass airflow relative to actual mass flow, depending on the hardware itself. The problem then became, how do I use sensor measurement as a reference for correction to an airflow model when the sensor may unpredictably yield inaccurate results? It is easy enough to pick the error out of a graph with your eyes, but not so easy within a set of collected data, and definitely not possible with HP Tuners due to the slow data collection rate and limitations of the scanner itself. I used to calibrate with a tool called Inca which was capable of data collection as fast as the controller execution loops updated the variables...but that doesn't happen on CAN that HPT uses. The data comes in scheduled and slow and doesn't provide a signal I can use that allows me to separate the error from it. Haven't figured out a way around that yet and not sure if I will. At least not without scripting in MATLAB, which few have access to.

That said, I've gotten requests a few times for a procedure on data filtering. Not really a 'part 2', but is still relevant and can help eliminate some error that you may find when calibrating with this procedure. Is there any interest for a 'how to' on data filtering?

10/10 Would like to see more on filtering data

[sgod1100]

Lol. So, my initial idea for a part two was to address an issue that compromised the results of this procedure....MAF reversion. If you're not familiar, this is a phenomenon that occurs (usually) with aftermarket intake tubes. Reversion is exactly what it sounds like - reversal of flow. When you add a camshaft that has a late IVC angle and/or pair it up with a new intake tube (or if you are bone stock, in the case of the LS2 GTO), often times what you've done is create an environment for 'pneumatic communication' of the camshaft with the MAF sensor. The big cam closes the intake valve late, and at low RPM pushes some charge back out of the cylinder before the valve closes. This causes a pressure rise in the intake and the reversal of flow. The flow reversal can result in high OR low measured mass airflow relative to actual mass flow, depending on the hardware itself. The problem then became, how do I use sensor measurement as a reference for correction to an airflow model when the sensor may unpredictably yield inaccurate results? It is easy enough to pick the error out of a graph with your eyes, but not so easy within a set of collected data, and definitely not possible with HP Tuners due to the slow data collection rate and limitations of the scanner itself. I used to calibrate with a tool called Inca which was capable of data collection as fast as the controller execution loops updated the variables...but that doesn't happen on CAN that HPT uses. The data comes in scheduled and slow and doesn't provide a signal I can use that allows me to separate the error from it. Haven't figured out a way around that yet and not sure if I will. At least not without scripting in MATLAB, which few have access to.

That said, I've gotten requests a few times for a procedure on data filtering. Not really a 'part 2', but is still relevant and can help eliminate some error that you may find when calibrating with this procedure. Is there any interest for a 'how to' on data filtering?

If that would help the reversion I'm getting in the V then absolutely I'd be interested!

[JtblckZ]

That said, I've gotten requests a few times for a procedure on data filtering. Not really a 'part 2', but is still relevant and can help eliminate some error that you may find when calibrating with this procedure. Is there any interest for a 'how to' on data filtering?

That's an absolute hell yes please!

[danmw2003]

Ive tried this method. Its sucks for noobs. Ended up starting over, the data I got from using this math was horrible. Steady state filtering of the throttle didnt help much as it wouldnt log much data at all. Being a manual trans, its really hard to have steady state when you're on an off the throttle in between shifts. Went back to failing the MAF and using LTFT to dial in my VVE

[eXo3901]

Seems to have worked for my GTO. It's just a low boost automatic but MAF/VE/Dynamic air all correlate very well with each other in the areas that can be reached on the street.

[marksrig]

I must be very confused. Does this even work on the E67? I cant find GMVE anywhere in maths or PIDs. What am I missing here? I think this is a USER defined math, but I'm just not getting the formula.

[ttz06vette]

Worked best for me just leaving in a gear on a highway and changing load then holding that change for awhile. I did it in 3rd, 4th, 5th, and 6th and got a ton of data.

[sgod1100]

Worked best for me just leaving in a gear on a highway and changing load then holding that change for awhile. I did it in 3rd, 4th, 5th, and 6th and got a ton of data.

that's typically what i do as well...can get those high load/low rpm cells pretty decent doing it this way

[sgod1100]

I must be very confused. Does this even work on the E67? I cant find GMVE anywhere in maths or PIDs. What am I missing here? I think this is a USER defined math, but I'm just not getting the formula.

Yes, GMVE is what you are getting from the formula and yes you are right it is a user defined math. Smokeshows equation goes in the circled area. Make sure you are logging all of the pids shown in the list below that
GMVE.JPG

[marksrig]

Yes, GMVE is what you are getting from the formula and yes you are right it is a user defined math. Smokeshows equation goes in the circled area. Make sure you are logging all of the pids shown in the list below that
GMVE.JPG

OK thanks, but I think I'll have to decipher the formula because it's not the same for the E67. For example, 16 isn't Mass Airflow in the E67 and there are several to choose from. This is the biggest issue I'm having at this point. Thank you for getting back to my question. And what does GMVE stand for exactly..?