MAF Tuning via STFTs problem
Thread Starter
On The Tree
Joined: Mar 2007
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From: Austin, Tx
MAF Tuning via STFTs problem So I got my VE table in line with LTFTs at 0--2 so I decided its time to re-enable the MAF and get it tuned. I can't seem to get the trims back into line. Any help on this would be appreciated. Maybe Im doing something wrong here.
I setup a histogram with my STFTs plotted against the Maf Airflow vs. Output Freq. Table (screen shot below), reset my fuel trims, and after I drive around for about 15-30 min. I take the data in the histogram and copy, special paste multiply by % to the Maf Calibration table.
Is that not correct?
The log included below is only a short 10min drive after a change to the maf calibration table. The screen shot is a shot of my histogram.
I setup a histogram with my STFTs plotted against the Maf Airflow vs. Output Freq. Table (screen shot below), reset my fuel trims, and after I drive around for about 15-30 min. I take the data in the histogram and copy, special paste multiply by % to the Maf Calibration table.
Is that not correct?
The log included below is only a short 10min drive after a change to the maf calibration table. The screen shot is a shot of my histogram.
why play with the MAF and VE numbers?? just do the VE with the MAF on. leave MAF numbers stock and enable PE mode to come on sooner, WAY WAY easier tuning and it works fine 
its how my car is setup
why do things the hard way....then again sometime i reckon its funner
its how my car is setupwhy do things the hard way....then again sometime i reckon its funner
Thread Starter
On The Tree
Joined: Mar 2007
Posts: 137
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From: Austin, Tx
I am under the impression that tuning the VE table in SD is the best way to go about tuning it (with WB of course) then put the vehicle back into MAF mode and make the MAF table match the VE. Is this not correct? I would assume that tuning the VE with the MAF enabled would be kinda like bandaiding the trims while under 4000rpm (i.e during throttle transients and what not when the computer looks toward the VE it would be incorrect if tuned while the MAF was still enabled.). Am I correct on that assumption?
why do all that? the MAF measures air coming in. adjust the VE to level off LTFT's to between -4 and 0.
you are doing the method right for what you want to do. What i'm asking is why do all that when you will get the SAME results faster and easier doing with the VE and PE mode lowered to come in and use it for fueling. I adjusted VE for fuel trims, made PE 12.1 AFR...and i snap the throttle down and BAM...12.2 AFR(seeing off of graph...not wideband, and I bet it would be 12.1x even on wideband. I can change my PE to 11.5 and it will be within .1 of the value. (Due to my FI kit coming close to limits of MAF, along with airflow values a little off)
the MAF and VE are blended no matter what on part throttle... you can change both or change one, really doesn't matter. if you change just one (assuming changing the VE) then you will not need to fake/confuse the computer with changed MAF numbers thinking its getting more airflow values, when you are compensating for changes via the VE table.
so adjust just the VE table... and watch your fuel trims go away
you are doing the method right for what you want to do. What i'm asking is why do all that when you will get the SAME results faster and easier doing with the VE and PE mode lowered to come in and use it for fueling. I adjusted VE for fuel trims, made PE 12.1 AFR...and i snap the throttle down and BAM...12.2 AFR(seeing off of graph...not wideband, and I bet it would be 12.1x even on wideband. I can change my PE to 11.5 and it will be within .1 of the value. (Due to my FI kit coming close to limits of MAF, along with airflow values a little off)
the MAF and VE are blended no matter what on part throttle... you can change both or change one, really doesn't matter. if you change just one (assuming changing the VE) then you will not need to fake/confuse the computer with changed MAF numbers thinking its getting more airflow values, when you are compensating for changes via the VE table.
so adjust just the VE table... and watch your fuel trims go away
Last edited by ZL1Killa; May 8, 2007 at 08:29 AM.
Originally Posted by ZL1Killa
why do all that? the MAF measures air coming in. adjust the VE to level off LTFT's to between -4 and 0.
you are doing the method right for what you want to do. What i'm asking is why do all that when you will get the SAME results faster and easier doing with the VE and PE mode lowered to come in and use it for fueling. I adjusted VE for fuel trims, made PE 12.1 AFR...and i snap the throttle down and BAM...12.2 AFR(seeing off of graph...not wideband, and I bet it would be 12.1x even on wideband. I can change my PE to 11.5 and it will be within .1 of the value. (Due to my FI kit coming close to limits of MAF, along with airflow values a little off)
the MAF and VE are blended no matter what on part throttle... you can change both or change one, really doesn't matter. if you change just one (assuming changing the VE) then you will not need to fake/confuse the computer with changed MAF numbers thinking its getting more airflow values, when you are compensating for changes via the VE table.
so adjust just the VE table... and watch your fuel trims go away
you are doing the method right for what you want to do. What i'm asking is why do all that when you will get the SAME results faster and easier doing with the VE and PE mode lowered to come in and use it for fueling. I adjusted VE for fuel trims, made PE 12.1 AFR...and i snap the throttle down and BAM...12.2 AFR(seeing off of graph...not wideband, and I bet it would be 12.1x even on wideband. I can change my PE to 11.5 and it will be within .1 of the value. (Due to my FI kit coming close to limits of MAF, along with airflow values a little off)
the MAF and VE are blended no matter what on part throttle... you can change both or change one, really doesn't matter. if you change just one (assuming changing the VE) then you will not need to fake/confuse the computer with changed MAF numbers thinking its getting more airflow values, when you are compensating for changes via the VE table.
so adjust just the VE table... and watch your fuel trims go away
Originally Posted by ZL1Killa
why do all that? the MAF measures air coming in. adjust the VE to level off LTFT's to between -4 and 0.
you are doing the method right for what you want to do. What i'm asking is why do all that when you will get the SAME results faster and easier doing with the VE and PE mode lowered to come in and use it for fueling. I adjusted VE for fuel trims, made PE 12.1 AFR...and i snap the throttle down and BAM...12.2 AFR(seeing off of graph...not wideband, and I bet it would be 12.1x even on wideband. I can change my PE to 11.5 and it will be within .1 of the value. (Due to my FI kit coming close to limits of MAF, along with airflow values a little off)
the MAF and VE are blended no matter what on part throttle... you can change both or change one, really doesn't matter. if you change just one (assuming changing the VE) then you will not need to fake/confuse the computer with changed MAF numbers thinking its getting more airflow values, when you are compensating for changes via the VE table.
so adjust just the VE table... and watch your fuel trims go away
you are doing the method right for what you want to do. What i'm asking is why do all that when you will get the SAME results faster and easier doing with the VE and PE mode lowered to come in and use it for fueling. I adjusted VE for fuel trims, made PE 12.1 AFR...and i snap the throttle down and BAM...12.2 AFR(seeing off of graph...not wideband, and I bet it would be 12.1x even on wideband. I can change my PE to 11.5 and it will be within .1 of the value. (Due to my FI kit coming close to limits of MAF, along with airflow values a little off)
the MAF and VE are blended no matter what on part throttle... you can change both or change one, really doesn't matter. if you change just one (assuming changing the VE) then you will not need to fake/confuse the computer with changed MAF numbers thinking its getting more airflow values, when you are compensating for changes via the VE table.
so adjust just the VE table... and watch your fuel trims go away
Originally Posted by SSpdDmon
So are you saying that over 4000rpms (which according to my soft.ware is the point where the PCM relies on the MAF only) you can get commanded fueling to match actual fueling by changing the VE? If so, then this goes against the major theories behind the stickies and how people have been tuning their vehicles for the past 3+ years. I'm not trying to attack you. I just want to understand what it is you're seeing and why others haven't come forward with the same observations.
i'm not saying that about things above 4krpm with the VE, for those values use PE Mode...i don't know how i got to coming across that way, because that is wrong.
he said UNDER 4krpm.... which LTFT's can be leveled off using the VE table. I've done it and it works, and by not increasing both (MAF and VE, the VE tables are larger than normal yes, but MAF numbers are unchanged.)
anything ABOVE 4krpm I have used PE mode to control fueling, as my PE mode comes in sooner now and I have a STOCK MAF TABLE. my fueling is fine...12.2 AFR done by the PE table
I honestly have no clue how i came across as using the VE table above 4krpm.....maybe it was a late night last night or something.... idk but that is wrong and i know it.
Frost...am I saying something wrong..I'm trying to get across the same way that yours is tuned (along with mine)...i guess i'm saying it wrong.. have PE mode come in and control fueling??
Last edited by ZL1Killa; May 8, 2007 at 08:34 AM.
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Originally Posted by ZL1Killa
where did you see me saying that above 4krpm is the VE and MAF???
i'm not saying that about things above 4krpm with the VE, for those values use PE Mode...i don't know how i got to coming across that way, because that is wrong.
he said UNDER 4krpm.... which LTFT's can be leveled off using the VE table. I've done it and it works, and by not increasing both (MAF and VE, the VE tables are larger than normal yes, but MAF numbers are unchanged.)
anything ABOVE 4krpm I have used PE mode to control fueling, as my PE mode comes in sooner now and I have a STOCK MAF TABLE. my fueling is fine...12.2 AFR done by the PE table
I honestly have no clue how i came across as using the VE table above 4krpm.....maybe it was a late night last night or something.... idk but that is wrong and i know it.
Frost...am I saying something wrong..I'm trying to get across the same way that yours is tuned (along with mine)...i guess i'm saying it wrong.. have PE mode come in and control fueling??
i'm not saying that about things above 4krpm with the VE, for those values use PE Mode...i don't know how i got to coming across that way, because that is wrong.
he said UNDER 4krpm.... which LTFT's can be leveled off using the VE table. I've done it and it works, and by not increasing both (MAF and VE, the VE tables are larger than normal yes, but MAF numbers are unchanged.)
anything ABOVE 4krpm I have used PE mode to control fueling, as my PE mode comes in sooner now and I have a STOCK MAF TABLE. my fueling is fine...12.2 AFR done by the PE table
I honestly have no clue how i came across as using the VE table above 4krpm.....maybe it was a late night last night or something.... idk but that is wrong and i know it.
Frost...am I saying something wrong..I'm trying to get across the same way that yours is tuned (along with mine)...i guess i'm saying it wrong.. have PE mode come in and control fueling??
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Verdad Gallardo Thread Starter
On The Tree
Joined: Mar 2007
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From: Austin, Tx
Well this turned into an interesting thread....
So what ZL1Killa is saying will work, but as Frost is saying that is still "fudging" the tables like I thought.
I do plan on keeping the MAF untill I really no longer need it (FI setup) but I would like to have all my tables reading as accuratly as possible without tricking anything, so the way I stated in the first thread about how Im trying to dial in my MAF is that the correct way of doing it or is there another way which will be more accurate in the end?
So what ZL1Killa is saying will work, but as Frost is saying that is still "fudging" the tables like I thought.
I do plan on keeping the MAF untill I really no longer need it (FI setup) but I would like to have all my tables reading as accuratly as possible without tricking anything, so the way I stated in the first thread about how Im trying to dial in my MAF is that the correct way of doing it or is there another way which will be more accurate in the end?
sounds like he is overcompensating the MAF table with VE.....MAF is not a live measurement device, frequencies are compared to a look up table to determine airflow, which can be skewed easily by turbulence and changes in intake tract....
Originally Posted by ZL1Killa
.....
Frost...am I saying something wrong..I'm trying to get across the same way that yours is tuned (along with mine)...i guess i'm saying it wrong.. have PE mode come in and control fueling??
Frost...am I saying something wrong..I'm trying to get across the same way that yours is tuned (along with mine)...i guess i'm saying it wrong.. have PE mode come in and control fueling??
No not wrong, it's just against the grain for the current tuning trend. I did it to get me by until I can get my 2/3bar tune done (but have tuning lined up like every night....so I tune everyone else's car except my own
) I did a 2-bar vette a few weeks ago and was amazed how easy it was. As soon as I get some time on my schedule my car will move to 2-bar SD.For now, this fudging works though and I am at 10.6-10.8:1 on pump gas and meth at 16psi regardless of outside temperature (my boost controller works!) and the car is STRONG.
Last edited by Frost; May 8, 2007 at 02:22 PM.
Thread Starter
On The Tree
Joined: Mar 2007
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From: Austin, Tx
Well ZL1Killa I suppose I will try your way out with adjusting the VE table while the MAF is enabled. I suppose it does not matter much because when racing I will be using the PE table right? Currently I have that set to target 12.8...I just want the real quick, smooth throttle response that I know will come from VE and MAF tuning the way that I was trying to do it. Which Im still wondering if that is a correct way to do it.
