Challenge to EFILive Tuning Concept:

[WeathermanShawn]

First, my "challenge" is meant in the utmost respect, and in the spirit of not only accelerating my own learning curve, but also those other users who obviously struggle with the same aspects of the more intricate concepts involved in the AUTOVE, EFILive tuning concepts. First off, I don't possess an engineering degree, but as a Meteorologist I do have a fundamental understanding of the properties of thermodynamics, air density, and airflow.

You would be surprised at examples of where the ideal gas law, while accurate in theory, has many pitfalls as it concerns to practical applications. I.E., drive through a significant temperature inversion and watch the dramatic changes in air density, and watch your tune go through some erratic fueling changes.

So, here is my question. I live in a state (Colorado), where elevation, air density, emissions etc, are ultimately going to require me to do the following:

1.) I have done the AutoVe (OLSD). I have also done the AutoVE (OLMAF).
2.) Due to the above mentioned limitations I must adjust to, here are my tuning requirements.

A). I will be running MAF.
B). I will be going back to closed loop utilizing narrow-band O2 readings, trims etc.

Bottom Line: I have spent a good 12 hours searching both LS1tech.com, and EFILive Forums. On LS1tech.com, doing a search of "MAF" brings up 112 pages of numerous opinions, some objective, but a lot highly subjective.

Respectfully, can anyone give as precise of a successful methodology to tune your car for exactly the way that you will be actually running it? The methodology of AutoVETune, without MAF, and then re-introducing a new calibrated MAF Table back into the VE (SD) calculations, seems to lack a precise mathematical formula to actually substantiate how this blend will actually precisely give you a consistent and accurate AFR.

Proportional MAF BENS, then no proven and precise method to combine VE (SD) and MAF, really makes me question what we are really after. For myself and apparently for many others, we just want to maintain a target AFR, that still conforms to running a car in closed loop with a MAF, and narrow band output.

Is there any proven method to tune your car to target a AFR under the parameters I mentioned above? Again, I acknowledge I am a 'one-post' guy. I am missing something, or I am just expressing what others of countless users must also think. I mean absolutely no disrespect to EFILive, the users of this board. Do I have a point?

So please don't react as this being a negative criticism. Just answer as frankly as possible. Can I command exactly the AFR I want, using Closed loop, O2 feedback., MAF, and SD parameters.

I appreciate the users taking the time to evaluate my perspective, and would appreciate any constructive and educational answers.

[TAQuickness]

In OLSD you will need to spend more time with the PCM's temperature compensation parameters

In OLMAF, the nature of the MAF sensors compensates for the changes in air density

CL operation compensates for slack in the tune and physical defects (i.e. dirty MAF).

[TFZ_Z06]

In OLSD you will need to spend more time with the PCM's temperature compensation parameters

In OLMAF, the nature of the MAF sensors compensates for the changes in air density

CL operation compensates for slack in the tune and physical defects (i.e. dirty MAF).

I have often thought that we should complete VE and then correct to STP or some avg temp/pressure based on the area we live in.

[Ryan]

Hi Shawn,

I too am one of those "one-post" guys, but I thought I'd chime in. First off, it is important to note that the ideal gas law is just that--a law for ideal gases. These don't really exist, although the Noble gases come close and the IGL pretty accurately defines the way they behave in most conditions.

We do have other models that can describe the behavior of density
Now, if you have not already, I recommend reading RedHardSupra's blog (http://redhardsupra.blogspot.com/); there is a lot to learn from that will give you a better understanding of what should be your goal as a tuner.

I am not so much in favor of using the "AutoVE/AutoMAF" method for tuning the MAF as the curve is described by a third-order polynomial and not just random values. If you can gather enough data, you can fit a new polynomial to match and make a new curve.

The PCM blends inputs from the MAF and VE table with a few other factors. From what I've read, the MAF is the most dominant factor in calculating air mass, but if either of the tables describing sensor input are wrong, it won't work correctly. I would expect that in closed-loop operation, the air mass is calculated in the same way as open-loop, but with the fuel trims adjusting the final calculated mass.

Provided you have all working sensors, current methodology says that you should go through the AutoVE process, then AutoMAF, then put the engine back into closed loop mode. At this point, you could use a wideband O2 sensor to monitor your narrowband switch points at stoich and adjust them accordingly.

Can I command exactly the AFR I want, using Closed loop, O2 feedback., MAF, and SD parameters.

The point of closed-loop operating is that it attempts to maintain a constant AFR close to the stoichiometric ratio for the fuel. I suppose you could do this by fooling the switch points while monitoring with a wideband, but the narrowband sensors are designed to function right around stoich, hence the name. All else correct, you can use PE modifiers to get the commanded AFR you want at "non-steady" conditions.

[Delco]

First, my "challenge" is meant in the utmost respect, and in the spirit of not only accelerating my own learning curve, but also those other users who obviously struggle with the same aspects of the more intricate concepts involved in the AUTOVE, EFILive tuning concepts.

First off, I don't possess an engineering degree, but as a Meteorologist I do have a fundamental understanding of the properties of thermodynamics, air density, and airflow.

You would be surprised at examples of where the ideal gas law, while accurate in theory, has many pitfalls as it concerns to practical applications. I.E., drive through a significant temperature inversion and watch the dramatic changes in air density, and watch your tune go through some erratic fueling changes.

So, here is my question. I live in a state (Colorado), where elevation, air density, emissions etc, are ultimately going to require me to do the following:

1.) I have done the AutoVe (OLSD). I have also done the AutoVE (OLMAF).
2.) Due to the above mentioned limitations I must adjust to, here are my tuning requirements.

A). I will be running MAF.
B). I will be going back to closed loop utilizing narrow-band O2 readings, trims etc.

Bottom Line: I have spent a good 12 hours searching both LS1tech.com, and EFILive Forums. On LS1tech.com, doing a search of "MAF" brings up 112 pages of numerous opinions, some objective, but a lot highly subjective.

Respectfully, can anyone give as precise of a successful methodology to tune your car for exactly the way that you will be actually running it?

The methodology of AutoVETune, without MAF, and then re-introducing a new calibrated MAF Table back into the VE (SD) calculations, seems to lack a precise mathematical formula to actually substantiate how this blend will actually precisely give you a consistent and accurate AFR.

Proportional MAF BENS, then no proven and precise method to combine VE (SD) and MAF, really makes me question what we are really after.

For myself and apparently for many others, we just want to maintain a target AFR, that still conforms to running a car in closed loop with a MAF, and narrow band output.

Is there any proven method to tune your car to target a AFR under the parameters I mentioned above?

Again, I acknowledge I am a 'one-post' guy. I am missing something, or I am just expessing what others of countless users must also think.

I mean absolutely no disrespect to EFILive, the users of this board. Do I have a point?

So please don't react as this being a negative criticism. Just answer as frankly as possible. Can I command exactly the AFR I want, using Closed loop, O2 feedback., MAF, and SD parameters.

I appreciate the users taking the time to evaluate my perspective, and would appreciate any constructive and educational answers.

Respectfully..

..WeathermanShawn..

Yes you can but remember we dont live in a ideal world where you have total control of the atmosperic conditions.

When I did OEM engine calibrations to do the base calibrations we used to have the engine in a fully climate controlled dyno cell , then a full range of tuning was undertaken at different atmospheric pressure conditions , temperature and humidity with only changine one variable at a time until we had a optimium tune that satisfied all the requirements of power , economy , emissions , durabilty and NHV , this took a team of 8 techs running the dyno 24/7 approx 1 month to get in the ballpark , make a minor change like filter housing or intake/exhaust system and the whole regime would start again.

Can you do this on the road and a rolling road - the answer is yes BUT expect to take 4-5 years to get the tune nailed to that level ( and remebering you are only looking at 3% of the possible tuning variables in most tuning tools on the market ) huge amounts of logging and analysing the data , even then you are most likely only to optimise for power and economy

Do the best you can , play with the tune daily and enjoy the experience knowing like teh real world nothing will ever be perfect.

[Ryan]

When I did OEM engine calibrations to do the base calibrations we used to have the engine in a fully climate controlled dyno cell , then a full range of tuning was undertaken at different atmospheric pressure conditions , temperature and humidity with only changine one variable at a time until we had a optimium tune that satisfied all the requirements of power , economy , emissions , durabilty and NHV , this took a team of 8 techs running the dyno 24/7 approx 1 month to get in the ballpark , make a minor change like filter housing or intake/exhaust system and the whole regime would start again.

Can you elaborate on this any more? I would really like to know more about the methods utilized by the factory.

[WeathermanShawn]

First, let me thank everyone for their replies.

I am always amazed by the general expertise exhibited by many members on this board.

Ryan and Delco, I was especially intrigued by many of your observations. (not to exclude you TAQuickness). I appreciate your honesty in describing the impractically of obtaining a "perfect" tune outside of a climate-controlled dyno lab.

I was beginning to question the practicality of my "open-road' tuning methods. Utilizing some fairly deserted wide-open roads in Eastern Colorado. Not the safest "dyno lab", and hard to maintain temperature and elevation data in a consistent manner.

On the subject of "AutoVE/AutoMAF. I also have read many of "RedhardSupra's" readings and blog. Smart person..I'm still a little behind in my learning curve vs his, so I have have some more learning to do.

It is perplexing to solve VE (SD) without MAF, then reintroduce the MAF variable and really expect a precise calibration. Especially in associating MAF HZ, with a particular AFR. Thats my hang-up. I can understand calibrating MAF HZ to a particular MAF flow..But applying AFR Ben's from MAF frequencies, will take me a little longer to fully comprehend.

So the bottom line is this. Is it a more reliable method to calibrate GM.MAFFREQ vs GM.DYNAIR (In OLSD)? I've seen and read all the debates, but is it a proven and reliable method?

Is simply matching the SD DYNAIR and matching it perfectly to MAF FREQ sound science?

As you all have stated, nothing is perfect and I that I understand. Ultimately tuning VE with all the parameters included would be the ultimate. I understand as a Meteorologist, thats virtually impossible to do.

Thanks again. I appreciate all the comments, and if anyone else feels like adding to the conversation, please do.

Remember, I am wanting to make it as simple and practicable as possible.

Commanded AFR's with VE's tuned in, MAF, and closed loop capability.

Thanks again.

..WeathermanShawn..

So the

[Ryan]

It is perplexing to solve VE (SD) without MAF, then reintroduce the MAF variable and really expect a precise calibration. Especially in associating MAF HZ, with a particular AFR. Thats my hang-up. I can understand calibrating MAF HZ to a particular MAF flow..But applying AFR Ben's from MAF frequencies, will take me a little longer to fully comprehend.

Solving for VE without the MAF seems odd, since the MAF seems to be the dominant influence in airflow calculations when in normal operation; the VE table (I think) was intended for transient throttle conditions.

With the AutoMAF method, we aren't associating MAF frequency with an AFR. The AFR is just a ratio between air mass (or airflow) and fuel mass (or fuel flow). Ideally, we are able to monitor fuel flow through our scanned PIDs, which means calculating the airflow is as simple as multiplying the two.

The BENs are simply a ratio of the observed and commanded AFRs. By multiplying our VE table (or MAF curve) by the BEN factors, we are ideally correcting our values.

So the bottom line is this. Is it a more reliable method to calibrate GM.MAFFREQ vs GM.DYNAIR (In OLSD)? I've seen and read all the debates, but is it a proven and reliable method?

If I am understanding you correctly, you are asking if it is possible to log MAF frequency along with dynamic airflow from SD calculations and plot the latter onto the MAF curve? If so, I suppose that is possible, but it will require you to have an accurate VE table. I am not sure if this is the "correct" way of doing things, because if the VE table was meant to compensate for transient conditions and the MAF was intended for steady state operation, we are doing things backwards by using AutoVE to recreate a VE table under steady conditions (which you are doing if you are applying the filter recommended by the tutorial).

[WeathermanShawn]

Ryan:

Thanks for your reply and clarification.

I think at this point I should just continue further logging and refining the parameters of MAF calibration as described in the AutoMaf "tutorials".

I can always separately log MAFFREq vs SGM.DYNAIR (while in OLSD mode) and make some comparisons.

I think you along with other users recognize an inherent difficulty in computing a VE curve (SD..excluding MAF airflow), and then separately re-introducing MAF airflow and it's contribution to fueling.

While RedHardSupra and others provide some brilliant insight into the fact that SD computations can be done without MAF, its pretty vague on the exact proportions of the MAF contribution airflow and it's precise effect on the resulting fueling changes.

Some discussions I've read insist that the MAF BEN's calibrations factors are not a one-to-one ratio. Some suggest 1/3-1/2 BEN's. Thats suggest to me that the methodology lacks a precision and accuracy to make many users confident of the results.

So, my point is not to be construed as argumentative. It is simply respectfully challenging the concept of two differing methods of calculating fuel based on two methods of determining airflow. One which excludes MAF, and then the other re-introducing a MAF airflow which by all accounts still utilizes airflow computations based on some degree by your original AutoVE (SD) .

Perhaps I am just discovering what many others have already comprehended. My main point is that as a relatively new user to EFILive and tuning, and from numerous searches on MAf calibrations, the 112 pages of search-related "MAF" questions on LS1Tech.com, and the general perception that very few people have a good grasp on this concept.

Since confusion is not just limited to people with little background in science or engineering, I think the "problem" is that perhaps any tuning method is not just a one or two step procedure (remains me of calculus).

I appreciate all the input. I humbly acknowledge I still have a lot to learn, and in no way am I giving up or criticizing the amazing capabilities of advancing tuning methods such as EFILive.

Does anyone acknowledge that if the ability to tune a car as a system (one or two step tuning)..I.E. tuning VE's, MAF, closed loop, etc existed, you could probably advance tuning theory in such a way that many more people would avail themselves of it, and the developer would probably be rich beyond means.

My conclusion is fairly factual. I tuned OLSD, tuned OLMAF, and when I combined the two to tune the car in the way I intended to always run it (Closed Loop), the combined total integration of the tuning methods didn't quite equal the results expected from the many hours put into it.

Again, I am just giving objective feedback with no disrespect to the product. Promise, I won't give up trying, but makes me wonder how people less motivated stick with a fairly complex concept and deal with the various modifiers and parameters.

Just reminds me of Calculus. Eventually got it, but lost half our class by the end of the course.

Anybody else feel the same, or have some constructive ideas on a more 'total system' approach?

Sorry for the length of the post. Just trying to learn.

Respectfully

..WeathermanShawn..

[TAQuickness]

$0.02 - Thinking of the air mass model in an LS1 F-Bod application...

The PCM incorperates 2 air mass models, VE and MAF


Under factory calibration:

• The PCM will use a blend of VE & MAF tables under 4000 RPM. The more steady state the condition, and/or as the engine speed moves closer to 4000 RPM, the more bias to the MAF
• Above 4000 RPM, the MAF is used exclusively as the air mass model
• Under P0101, P0102, P0103, or any other MAF failure, the PCM will use the VE table exclusively as the air mass model

We also know that in OEM trim the MAF is not functioning in an ideal installation - hence the screen and air foils.

Knowing the basic PCM operation regarding VE and MAF, we utilize the VE table as the base air mass model. Once we have calibrated the VE table, we now have a known control constant to base our MAF tuning efforts on.

I do believe it's possible to use the MAF as the base air mass model then tune the VE. (i.e. disable use of the VE table, calibrate MAF, enable VE table and use AutoVE to compensate the differences). Keep in mind though:

• When a MAP sensor fails, the PCM does not resort to the MAF table.
• In the event of a MAF failure, the PCM resorts to the VE table (in this case would be tuned to compesate a MAF).