Simple MAF/DYNAIR pid question.

[acomp917]

Hello All,

I have been graphing SAE.MAF to GM.DYNAIR in an effort to see if the VE air flow/mass matches the MAF. I'm noticing that during tipin the VE shows reduced flow(in comparison) and the opposite during tipout. This indicates that the slope of the VE table needs increased(with respect to vac).

Question:
Is it reasonable to assume that if I calc.pid MAF/DYNAIR and apply the resultant factor to the VE table, that would create matching and working air mass calculations?

I assume that ALL modifiers(IE temp) are consistent to both the MAF and DYNAIR pids at any given moment.

Starting simply,
S

[joecar]

Also compare with GM.MAF.

[WeathermanShawn]

Question:
Is it reasonable to assume that if I calc.pid MAF/DYNAIR and apply the resultant factor to the VE table, that would create matching and working air mass calculations?

I assume that ALL modifiers(IE temp) are consistent to both the MAF and DYNAIR pids at any given moment.

S

Its that second assumption that is not necessarily correct. The DYNCYLAIR (SD) does not take into account all the temperature modifiers.

Don't know if that is what you are asking, but I ran into that reality lately. Are we talking about the same PID(S)?

[acomp917]

Thanks Shawn,

I know the platform is not open, but could you tell me how you determined that the density modifiers are not used on SD. That is a basic prerequisite of SD.

S

[WeathermanShawn]

I will do my best. I want to first make sure we are describing the same PID(s).

1. GM.CYLAIR.DMA Air Flow Grams/Cyl ..MAF Airflow
2. GM.DYNAIR.DMA Air Flow Grams/Cyl..Speed Density

If those are the same PID(S), I have logged each but I have not found that the GM.DYNAIR.DMA reflects the Airflow after all of the charge temperature calculations, modifiers etc., have been calculated.

It appears to be the dynamic airflow prior to the modifications. As always, Joecar can explain a lot better than me. But, I can certainly provide numerous logs that show the same dynamic airflow..regardless of charge temperature, filters, etc.

Again, I want to make sure we are talking about the same thing. But I recently ran into a huge roadblock trying to figure out the same thing.

[acomp917]

Shawn,

Not cylair or variant. just gm.dynair vs. sae/gm.maf. Those are measured in gm/sec. They are calculated from VE table and measured from MAF. I have some difference(see Post#1) btwn the two and would like to simply factor the difference into the VE in order to make both the same.

In my short sight, I trust the MAF cal. I will use it to create VE table. I will adjust IFR in an effort to set AFR with consideration to new timing map. This is a stock system. It seems to be a simple method of balancing the tune. It has already responded favorably to my harsh adjustments.

S

[WeathermanShawn]

Sometimes these PID(S) are simply reflecting a Table look-up (user-input).

I have just learned to distinguish between what is being calculated, and what is just simply a Table Look-up.

We are probably talking about two different things.

Hopefully you got it straight.

[redhardsupra]

Shawn,

In my short sight, I trust the MAF cal. I will use it to create VE table. I will adjust IFR in an effort to set AFR with consideration to new timing map. This is a stock system. It seems to be a simple method of balancing the tune. It has already responded favorably to my harsh adjustments.

S

you mean IFR hacking because you changed spark? How does spark affect IFR or any of it's components?

[acomp917]

RHS,

I'm using SSpdDmon's method of leaving the MAF cal stock. The only method that I know to change the LTFT's in a MAF system is using IFR. There was a considerable change (10%) from factory IFR as an initial hack. With original trim(6%) and timing changes(another 2%), plus 2% to put the trims in the ~-2% range. I have only done preliminary changes, now the real tuning can take place.

I have the first impression that this is a simple and good way to proceed. I also think the VE cal factor can be created by a simple MAF/DYNAIR calc.pid.

To be honest with you, this PCM is very easy to tune. The EFIL system is very good and the forums are full of helpful info. I first thought I'd hate not being able to "real-time" tune. I'm thinking that this method is better, maybe more scientific.

S

[ScarabEpic22]

...
To be honest with you, this PCM is very easy to tune. The EFIL system is very good and the forums are full of helpful info. I first thought I'd hate not being able to "real-time" tune. I'm thinking that this method is better, maybe more scientific.

S

If you want to tune in Real Time, buy a RoadRunner PCM from Moates. Can update everything on-the-fly.

[joecar]

...
The only method that I know to change the LTFT's in a MAF system is using IFR.
...
S,

You can also change the MAF table itself.

[redhardsupra]

Its that second assumption that is not necessarily correct. The DYNCYLAIR (SD) does not take into account all the temperature modifiers.

Don't know if that is what you are asking, but I ran into that reality lately. Are we talking about the same PID(S)?

All this has been beaten to death 3-4yrs ago:

http://forum.efilive.com/showthread.php?t=9204

http://forum.efilive.com/showthread.php?t=4709

http://forum.efilive.com/showthread.php?t=3017

May the search force be with you ;)

[WeathermanShawn]

Marcin I have read all that.

It is not current. A week ago you told me dynamic and cylinder airflow should match.

You were wrong.

[redhardsupra]

RHS,

I'm using SSpdDmon's method of leaving the MAF cal stock. The only method that I know to change the LTFT's in a MAF system is using IFR. There was a considerable change (10%) from factory IFR as an initial hack. With original trim(6%) and timing changes(another 2%), plus 2% to put the trims in the ~-2% range. I have only done preliminary changes, now the real tuning can take place.


here's how the discussion between me and Jeff went:
Jeff: SD/MAF is too troublesome, i'm going pure MAF
Jeff, 2 days later: well, maybe MAF alone cannot account for every change that occurs in the airflow or fuelflow, so I'll start changing IFR to make up for it!
me: so you're adjusting IFR to make up for the MAP/MANVAC based changes. Why don't you also add RPM based changes to it, and just call it the VE table?

usually it's just easier to work with the system, not against it...

[redhardsupra]

Marcin I have read all that.

It is not current. A week ago you told me dynamic and cylinder airflow should match.

You were wrong.

hmm? have old OS's changed since then?

How am I wrong? If you're measuring the same physical entity two different ways, shouldn't you get the same result?

If you get different results depending on which method of measurement you're using, I'd be willing to bet a good amount of money that it's your measurement methodology that's flawed.

[WeathermanShawn]

hmm? have old OS's changed since then?

How am I wrong? If you're measuring the same physical entity two different ways, shouldn't you get the same result?

If you get different results depending on which method of measurement you're using, I'd be willing to be a good amount of money that it's your measurement methodology that's flawed.

What I am saying is that GM.DYNCYLAIR does not take into account all the temperature biases you always preach. Matching DYNCYLAIR and CYLAIR is not accurate (you said it was).

[redhardsupra]

I have not seen any proof of what you speak of. Link me, please.

[WeathermanShawn]

Marcin quote:

I absolutely agree that no matter what airflow model you're using, the airflows need to be identical. I will go even further with this statement, and say that they need to agree across the full range of airflows.

Marcin 2007 Quote:

what's the difference between DYNAIRTMP_DMA vs CHRGTEMP_DMA?

I'm looking for a PID that would give me aircharge temp, blended accordingly to airflow and B0115 (newer) or B4901 (older)

also, does anyone know how to add *Kelvin to the general selection so I dont have to make extra custom PIDs for it

Originally Posted by redhardsupra
Here's a longer list of PIDs, could someone please enlighten me as to which ones do exactly what, what platforms they occur on, etc... I have an idea about most of them, but i'd like to hear others' take on some of them.

GM.DYNAIRTMP_DMA - I would guess this is the IAT used at a given instant during SD calculations????
GM.CHRGTEMP_DMA - Calculated charge temperature based on IAT, ECT, Charge Temp Blending, and Charge Temp Filter.

GM.DYNCYLAIR - The PCM's predicted airflow values...maybe based on changes observed in short-term histories and observed/filtered changes? In other words, I believe this pid is designed around transitional throttle.
GM.DYNCYLAIR_DMA - The current grams/cyl. value being used in SD fueling calculations. If the MAF is active, GM.CYLAIR_DMA is the pid to use.
CALC.CYLAIR - EFI Live's calculated grams/cyl. based on MAF flow and RPM.

Sounds like you were pretty confused as a 'newbie'.

If you are saying that GM.DYNCYLAIR.DMA is the airflow after these calculations you need to do some logging. Matching DYNCYLAIR and CYLAIR is easy. But that DYNCYLAIR does not calculate the charge temperature and biases. I can provide numerous logs indicating that.

I have had several people verify that.

VE*MAP/charge temperature

273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.

Its a myth..

[acomp917]

joecar,
Of course the MAF cal could be adjusted. I'm currently subscribing to the SSpdDmon method. After weighing all(that I know) the cause/effect, I think it is the best 90 percentile approach. I hate going for that last 10%, the returns are not good.

I have not calc'd GM.MAF/GM.DYNAIR yet.

RHS,
I would not say that this has been beaten to death. I think due to limited understanding of exact pid specs, most people are measuring what exits the system with a known sensor(WBO2). I'm not saying that doing so is wrong. In light of missing specs, it might be the only method.

ScarabEpic22,
If I did not need EPA cert. and I had to go to that $$$, I would use an Accel(might like to try BS3).

Shawn,
There is very little conclusive data about the inner workings of this PCM. If you include the human variable, you might find yourself to be better off proofing the data yourself.

To All,
I think I have a semi-plugged injector. After I had to change the IFR 10%(might have gone ~2% too far), I began to think... Then I noticed an occasional knock where there should not be one. I just used DVT to shut off injectors and found I do have a weak cylinder. Just another hassle!

S

[WeathermanShawn]

I have done SSpdDmon's IFR method.

It is fast and the easiest method to correct Fuel Trims. You are left with a pretty lousy VE Table though..it might not bite you unless your MAF fails. My wife's Monte Carlo's MAF just failed..so of course it happens.

When you change those IFR settings, all your airflow calculations must be also adjusted. I agree with your general observation. I have correct IFR settings, correct MAF, and to this day no one can perfectly describe how the VE Table is used. Otherwise it could be done simply. And 4 years later we all still argue over it.

Part of is that you can arrive at a differing calculation in the event of MAF failure than a VE/MAF blend.

If you are MAF, closed-loop you can get away with a lot. As long as your transient fueling, cruise, and WOT match..well then your only concern is MAF failure..but in all honesty you don't have to get it perfect.

[acomp917]

RHS,

About the Me and Jeff post.

I mapped SAE.MAF/GM.DYNAIR. The ONLY discrepancy was during tip in/out. This indicates either the VE needs more slope(inversely prop. to map) or the SAE.MAF is not using the TauX (wall wetting) parameter. I have yet to think enough to check that. I guess I could bash the TauX and see what happens. A GUESS IS MAF IS NOT USING TAUX.


Jeff, 2 days later: well, maybe MAF alone cannot account for every change that occurs in the airflow or fuelflow, so I'll start changing IFR to make up for it!
Wonder what he found exactly?



me: so you're adjusting IFR to make up for the MAP/MANVAC based changes. Why don't you also add RPM based changes to it, and just call it the VE table?

You sure have a problem with IFR adjustments. I have been an electronics tech for 30 years and a mechanic since a child. I know that balancing an inductive load considering vac differential/transient and moving mass is going to take a very long time. According to what I know of your standards... IFR is basically crap. For a give (constant) situation, I think I'll trust the MAF calibration.



S

[acomp917]

Shawn,

Changing the IFR will just change the entire VE table a corresponding % directly proportional to IFR. I kept it simple, that assumes changing the entire IFR a given %. Of course the VAC.psi(stupid) and VAC.kPa would have to be converted.

I don't know why you say all of the air flow settings must be changed. All that was done was an adjustment to the calculated fuel mass. I have to ponder this. My trk is still re-learning, I will check this when it stabilizes.

^ Ah Ha, My intention was not to change the VE overall, it was to change the LTFT from +6 to ~-2. The contour will change to reflect timing changes and AFR changes under PE. GM's tune was timing and fuel safe. If a person has .5 brains... they could not make it much worse.

There is no mystery to the basic VE table. It is just a 3d lookup table(with interpolation) that reflects the engine's ability to fill the cylinders, based on RPM(speed) and VAC(density)... hence SD. Of course the retrieved number is but one part of a much bigger algorithm. That is the mystery when dealing with these dam GM systems.

S

[acomp917]

A reconsider,

About that not being able to wreck a factory tune... Has anyone looked into some the modified tunes on holden crazy? Brings to mind the anvil and rubber hammer analogy. Does anyone think those tuners ever looked at the fuel tables after they were modified? Looks like non-filtered autoVE and NO knowledge.

S

[WeathermanShawn]

No, I understand what you are doing.

IMO, a 10% change in your Injector Flow Rate (IFW) is no different than a 10% across the entire MAF Calibration Table. Of course, with a IFW adjustment there is no load adjustment..spark tables. MAF there is.

I can run a 2002 stock Camaro VE Table in my car (other than idle:hihi:) with similar Trims, Commanded AFR, etc., as long as my MAF is calibrated. Where all of this gets fun is when you purposely fail the MAF. If you have a 20-30 % airflow difference, I bet your car won't run. So, no I am not faulting you. I am just preparing you for the answers you are about to hear from others. You have to occasionally fail your MAF to at least prove you have the correct airflow.

I know you are a smart guy with a background in mechanics. Others without the experience may want to try the same thing. Just be prepared. I barely challenged current thinking. And, I was not right about everything. Saying IFR adjustments on this forum will get you a lot of responses.

[acomp917]

Does anyone have an accurate dyno based tune for a stock LM7 5.3 truck. I'm not asking for the data, just a sanity check. I believe that hump in the VE should be pushed toward the lower RPM's. I know everything above 6k is a waste. This is the first hack. Waiting for the truck to re-learn before I can really find it's true personality.

Any opinions?

S

[joecar]

...

Changing the IFR will just change the entire VE table a corresponding % directly proportional to IFR. I kept it simple, that assumes changing the entire IFR a given %. Of course the VAC.psi(stupid) and VAC.kPa would have to be converted.
...S,

No, changing the IFR leaves the VE table as is (you have to edit the VE to change it)...

Changing the IFR changes the fuelmass delivered by the injectors, changing the measured AFR.

Same applies to IFR in relation to MAF table.

Also, as Shawn pointed out, changing the IFR doesn't change the load (which indexes into the spark tables)... changing the VE or MAF changes the load (airmass/cylinder).

:)

[acomp917]

Shawn,

I don't mind, I am a challenged thinker:redface: I mean I don't mind being challenged by thinkers. About that modifying load/spark tables: I have not found a basic running table that reflects spark with reference to MAF. I believe "load" is a function of MAP vs. RPM, ie. VE based. Would anyone please educate me about this if I am wrong?

Found my oversight.
joecar,
First, my writing is not very good.


No, changing the IFR leaves the VE table as is (you have to edit the VE to change it)...
I should have stated in order for fueling to remain constant, VE will need to be changed...

Changing the IFR changes the fuelmass delivered by the injectors, changing the measured AFR.
IFR changes affect the calculated fuel mass and only affect AFR in an OL system, else LTFT.

Same applies to IFR in relation to MAF table.
Don't understand your statement, though I do understand they are ALL relational.

Also, as Shawn pointed out, changing the IFR doesn't change the load (which indexes into the spark tables)... changing the VE or MAF does change the load... if the VE or MAF are correct, you get the correct spark timing (if the spark tables are correct).
I think I understand how load is calculated(correction above, maybe here too). F!@# the timing table values... GM did. ;)just kidding. I do know what you mean. Remember, we should try to maintain atleast one constant(I KNOW! I'm the person that neglected to do that :) ).


S

[acomp917]

A reconsider,

My apologies to joecar and Shawn. I did find that the spark table is referenced to GM.DYNCYLAIR vs. RPM vs. timing. This is the first system that I've tuned that used that g/cyl axis. As a matter of truth, this is the first system with a MAF that I have tuned.

Stands to reason. This allows the MAF to have access to spark timing... Now for the big question! What does a CL SD/MAF system use to determine base spark. I guess GM.cylair(MAF) and GM.DYNCYLAIR(SD). Any blending, precedence, or other?

While I'm askin... does it apply any additional modifiers? Oh yea, there is entire list. This thing will FU UP!

Gotta have somethin to do, :)
S

[joecar]

See my inline comments in this strange blue ink:


...


No, changing the IFR leaves the VE table as is (you have to edit the VE to change it)...
I should have stated in order for fueling to remain constant, VE will need to be changed...
ah, ok, yes that is correct;

Changing the IFR changes the fuelmass delivered by the injectors, changing the measured AFR.
IFR changes affect the calculated fuel mass and only affect AFR in an OL system,
changing the IFR changes the pulsewidth calculation which changes the delivered fuelmass, it does not change the calculated fuelmass (which is calculated from airmass and AFR);

else LTFT.
my understanding is this: in CL, the PCM first computes the required fuelmass and then uses O2 feedback to trim to stoich (i.e. the trim adds/subtracts fuel on top of the calculated fuelmass).

Same applies to IFR in relation to MAF table.
Don't understand your statement, though I do understand they are ALL relational.
If you change the IFR the MAF will also have to change to keep fueling the same.

Also, as Shawn pointed out, changing the IFR doesn't change the load (which indexes into the spark tables)... changing the VE or MAF does change the load... if the VE or MAF are correct, you get the correct spark timing (if the spark tables are correct).
I think I understand how load is calculated(correction above, maybe here too). F!@# the timing table values... GM did. ;)just kidding. I do know what you mean.
Yes, cylinder airmass is considered to represent load... this can be found in most ICE textbooks;

Remember, we should try to maintain atleast one constant(I KNOW! I'm the person that neglected to do that :) ).
No problem... in order to learn we must take a few steps and possibly make mistakes... it's the mistakes we learn our best lessons from... :D
we're all still learning this stuff... learning is like a closed loop algorithm that requires a few occasional open loop excursions.




:)

[WeathermanShawn]

Every big of logging I have done with MAF-Enabled has used the MAF calculated airflow (GM.CYLAIR). I know Table B5913 says "DYNCYLAIR", but if you hold the cursor over it, it lists multiple PIDS. I have not seen any influence of DYNCLYAIR affecting spark load when running MAF.

When I tested the IFR % change, my fueling (TRIMS) were fixed, but my load stayed the same, and my DYNCYLAIR and CYLAIR airflow values were off by the same % I had applied to the IFR.

The last week I have been running CLSD to compare against a MAF-based tune. With the MAF disabled, Table B5913 references GM.DYNCYLAIR. Of course with MAF disabled, I am running off the Low Octane Spark Table. With a custom OS, you have more options.

Those are some of the issues you face with a IFR adjustment. Sometimes Idle and decel can be 'rich' when IFR and airflow do not match. Meanwhile Trims and Commanded AFR look good. Something to think about.

[acomp917]

joecar,

I think we argue over semantics. I learned this stuff without ever reading a book or taking a class(used internet). I started this in the days of the GM 7747 ECU(hated those). My verbiage is usually wrong and my thinking is sometimes wrong.

I am eager to get some basic tuning done in order to see if I have wrecked the VE MAF relationship. I have been rough on the tables. Got fairly good at bashing in tables from setting up aftermarket EFI on most any engine combo that people wanted to build. This MAF system is slightly different and considerably more balanced. It is good that I decided to learn this system on a stock engine(read: easy).

Questions:
1- What are you doing with all of the other(not main) 3d timing tables?
2- Is there a big problem when they are not close to the main table?
3- Do you think I should analyze them in relation to the stock main table and and apply those differences to them based on my final modified main table?
4- Should #3 be done before any serious tuning?
5- What is ICE textbook?

I'll leave you alone after this,
S

PS, Seems that edits are emailed to subscribed members. I been goofin with BB code. Must look like a GOOF.:unsure:

[redhardsupra]

VE*MAP/charge temperature

273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.

Its a myth..

of course it's not gonna agree, for multiple reasons:
1. you're using VE not GMVE, so you're missing VOL and R
2. if you were using GMVE and checking your units, you'd be forced to use Kelvin for temps everywhere, which btw is the proper thing to do.
3. this model does not work for all model/years. newer cars have the Lag filter involved. even newer stuff has the bias table is dependent on airflow and speed, instead of just airflow alone. so which model are you testing on what platform?

[WeathermanShawn]

I am saying that GM.DYNCLYAIR.DMA is not calculating the airmass with any of the Temperature Bias tables input.

Therefore the identical dynamic and cylinder airflow you are searching for is not accurate. Do a log of dynamic and cylinder airflow. You won't see dynamic airflow change as your charge temperatures* factors change.

Matching dynamic and cylinder airflows will get you improper fueling.

[acomp917]

WOW!

You 3 have been very helpful. This kind of info takes a lot of time to acquire/proof. I'm very happy that I did not have to re-invent the wheel.

Shawn,
What about factoring air flow g/sec. ie. MAF/GM.DYNAIR? Searching for a method of factoring internal pids without using end result, WBO2.

RHS,
About that kelvin thing... not another temp scale, I have not warmed up to metric yet. :) I suppose I could print a SS that converts 20>240 every 10. What an absolute pain.

Thanks joecar, RHS, and Shawn,
S

[redhardsupra]

Sounds like you were pretty confused as a 'newbie'.


Oh yes, we all start at the same zero-knowledge state. Given enough time and education, some of us evolve. If it wasn't for all these posts back then, I wouldn't know much now. This is why it bugs me when sophomores like yourself refuse to learn from the mistakes of the people that have done it all before, yet you go out and end up having the same problems yourself. Why not leverage what's already there? There really is no need to reinvent the wheel.

[WeathermanShawn]

Marcin, its all in your attitude.

You have a great mind, but no one will ever follow you until you start treating people with respect.

We could learn from you if you changed your attitude.

[acomp917]

RHS,

After looking at that post, I cannot make anything from it. It seems to be incomplete. I'm still not sure what you call "charge" temp. Is this the IAT with another modifier or 2 included? ie. ECT blend, or MAT.



VE*MAP/charge temperature
What does this represent?

273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.
What factor does this represent? What is "this calibration"?

Its a myth..
This I understand. It refers to your providing usefool help ;)

S

[acomp917]

My big nose,

Marcin,

If I may use Your Name, you are an AZZ-O

Steve, Use it if you could possibly have a differing opinion.

[LinearX]

RHS,

After looking at that post, I cannot make anything from it. It seems to be incomplete. I'm still not sure what you call "charge" temp. Is this the IAT with another modifier or 2 included? ie. ECT blend, or MAT.



S

Would it be wrong of me to point out that you quoted Shawn, yet addressed Marcin?

[acomp917]

I'm takin my thread back.

On to a lighter subject... Why would anyone call a car "Maloo"? :)

This is not an acronym, ebonics, webonics, or any other Nonsensical Talk. Just trying to be funny.

S

[acomp917]

This the whole post, I seem to be having a delivery problem. That along with the "personalized" thread jacking is causing me problems.

RHS posted:



Quote:
VE*MAP/charge temperature

273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.

Its a myth..
of course it's not gonna agree, for multiple reasons:
1. you're using VE not GMVE, so you're missing VOL and R
2. if you were using GMVE and checking your units, you'd be forced to use Kelvin for temps everywhere, which btw is the proper thing to do.
3. this model does not work for all model/years. newer cars have the Lag filter involved. even newer stuff has the bias table is dependent on airflow and speed, instead of just airflow alone. so which model are you testing on what platform?
__________________


That is where things started DOWNHILL. Thanks, Marcin!

S, thread owner

[redhardsupra]

why would you name a car Probe? unless you're into dropping soap...

[acomp917]

Dam Marcin,

Have you run out of meds? Remember, before you were too smart to relate to others you spoke english(assumption). If you would remember where you have been...you will remember where you come from.

At my age I do not need another enemy, although I can live with that.


Now! have a beer. :cheers:

S

About that soap: Since the military, I only shower with members of the opposite sex. and THAT is what makes me happy. :grin:

[joecar]

...

Why would anyone call a car "Maloo"? :)

This is not an acronym, ebonics, webonics, or any other Nonsensical Talk. Just trying to be funny.
...It's the same marketing concept as "Camaro" and "Chevelle"... they are the proper names of mythical creatures yet to be discovered.

:D

[redhardsupra]

why would you name a car Probe? unless you're into dropping soap...

that supposed to be a joke, since you wanted to lighten up the mood.

And no, I was too smart to relate to people long before I spoke English. That's actually only a half-joke ;)

[acomp917]

joecar,

What are you, an alien? Those cars are AMERICAN heritage! What do they have to do with that car named "Maloo"? Oh, wait, this is the WWW. Am I being ignorant again? :doh:

:cheers:
S

If I ever market a car, I'm gonna call it the "PLATAPUSSY". (One too many beers for me) :grin:

[joecar]

See my inline comments in blue ink...


RHS,

After looking at that post, I cannot make anything from it. It seems to be incomplete. I'm still not sure what you call "charge" temp. Is this the IAT with another modifier or 2 included? ie. ECT blend, or MAT.




VE*MAP/charge temperature
What does this represent?
VE has units g*K/kPa, so VE*MAP/temp has units g (i.e. grams or grams/cylinder).

The ideal gas law is: PV = nRT = (m/M)RT
where:
P = pressure
V = volume
n = mole count
m = mass
M = molar mass (which is a constant for any particular gas)
R = gas constant
T = temperature (absolute temperature, degrees Kelvin)

If you rearrange the gas law you get: mT/P = V(M/R)
notice the left side has units g*K/kPa (and that (M/R) is constant)...
i.e. V(M/R) is our VE table value...
rearrange further: m = V(M/R)*P/T = VE*P/T = VE*MAP/temperature

i.e. the VE table contains the cylinder airmass scaled ("normalized") for pressure and temperature...

(when I say temperature, that is the blended charge temperature... see next point).

273.15+IAT+((ECT-IAT)*factor) where factor is obtained from this calibration.
What factor does this represent? What is "this calibration"?
This is the charge temperature which is a blend of IAT and ECT.
The 273.15 converts it to degrees Kelvin (absolute temperature).

...

S
:)

[joecar]

joecar,

I think we argue over semantics. I learned this stuff without ever reading a book or taking a class(used internet). I started this in the days of the GM 7747 ECU(hated those). My verbiage is usually wrong and my thinking is sometimes wrong.

I am eager to get some basic tuning done in order to see if I have wrecked the VE MAF relationship. I have been rough on the tables. Got fairly good at bashing in tables from setting up aftermarket EFI on most any engine combo that people wanted to build. This MAF system is slightly different and considerably more balanced. It is good that I decided to learn this system on a stock engine(read: easy).

Questions:
1- What are you doing with all of the other(not main) 3d timing tables?
2- Is there a big problem when they are not close to the main table?
3- Do you think I should analyze them in relation to the stock main table and and apply those differences to them based on my final modified main table?
4- Should #3 be done before any serious tuning?
5- What is ICE textbook?

I'll leave you alone after this,
S

PS, Seems that edits are emailed to subscribed members. I been goofin with BB code. Must look like a GOOF.:unsure:
It's not semantics...

delivered fuelmass and calculated fuelmass are different things... just like measured AFR and commanded AFR... the difference in what they are will drive your thoughts...

I learned this stuff by reading/asking/doing... I'm still scratching my head (I feel like a newb everyday)... :hihi: ...you're in for a good learn, probably the best in your whole life ever... :rockon:

1- the other timing tables (3D and otherwise) provide adjustments for temperature or for other engine modes... you make sure you run/log in the zero correction regions (or filter out anything outside of this) so you can ignore them;

2- maybe or maybe not... but, there has to be a reason why;

3- concentrate on the main table, but you will need dyno time or and/or dragstrip time;

4- I'm not sure... timing is difficult to set.

5- ICE = Internal Combustion Engine... I usually pick up a textbook or two every so often when Amazon has some kind of sale/deal... I'm slowly reading my way thru Heywood "Internal Combustion Engine Fundamentals"... long dry read with lots of engineering maths/charts (not for the non-engineer)... :cheers: ...Heywood is the engineer's equivalent of a "hero"... :rockon:


:D

[acomp917]

RHS,
Call me radical, I never liked fords. Chevy's forever!.

joecar,
I'll be back in a year to discuss this information. I do remember some of this from chemistry. I think my notes have crumbled due to erosion.

S

[joecar]

joecar,

What are you, an alien? Those cars are AMERICAN heritage! What do they have to do with that car named "Maloo"? Oh, wait, this is the WWW. Am I being ignorant again? :doh:

:cheers:
S

If I ever market a car, I'm gonna call it the "PLATAPUSSY". (One too many beers for me) :grin:Yes I am an alien... actually a resident-alien, I forget what my permit says... :)

American heritage, yes, I agree... but where did those names originate (nothing to do with www)...

(a Platypussy would [arguably] be named after a mammal... but a Camaro or a Chevelle is neither an animal nor a thing...).

:D

[acomp917]

Now that we are WAY off topic and my thread is ruined, What the heck is a Maloo anyway?

BTW, I took a long look at the ideal gas laws and I would be a long time getting through that. I'm not even able to access whether learning that would help my understanding of the EFI fueling process, maybe TauX.

I'm crushed.

Thanks for all of your help anyway. Now this ignorant yank must go sulk, :ermm:
S

[acomp917]

joecar,

I did wade through the ideal gas law/ temp post. Learned a LONG time ago. Makes good sense. Seems the air mass calculation is more of a standard than the charge temp calc. Companies have been messing with charge temp models for a long time.

I always assumed that the VE directly refered to air flow and cylairmass was a product of that. Seems to be the other way around. I don't suppose it really matters, cylairmass*cyl#*rpm(might have missed something)=air flow

I believe I at least get the concept.

Thanks again,
S