Help scaling MAF
I think I just need to log and retune again. I feel like I am getting knock on let off, when I shift, the AFR goes lean for a second, then bounces to rich... Everything is throwing me off. I didnt think hard pipes would do so much to a car.
Wait a minute here... Why would you need to add those 2? STFT is O2 feedback, i assume its average is used to adjust LTFT's (low or mid depending on feedback @certain airflow). So wouldn't you just look at LTFT number for the percentage at corresponding Hz?
As in for idle, if you idle at 50Hz and Low LTFT is -5 you would take the number from 50Hz (152 or whatever) add 140 subtract 5% then reduce it by 140 and put it in the table.
Do the same for cruise and smooth the table.
I mean STFT bounces all over most of the time, how would you add it?
Am i missing something here?
As in for idle, if you idle at 50Hz and Low LTFT is -5 you would take the number from 50Hz (152 or whatever) add 140 subtract 5% then reduce it by 140 and put it in the table.
Do the same for cruise and smooth the table.
I mean STFT bounces all over most of the time, how would you add it?
Am i missing something here?
BTW, my MAF scale table isn't in Hz because I wanted to load my ROM real fast for a screen shot. When I boot into Windows, it is represented in Hz.
Actually you got me all confused now. 
If it says -5 in you will need to subtract 5%.
If it says +5 you will need to add 5%.
And so on.
That's the same as Eric said and what i typed there...
If it says -5 in you will need to subtract 5%.
If it says +5 you will need to add 5%.
And so on.
That's the same as Eric said and what i typed there...
First, thanks for the reply Eric. I read your Excel spreadsheet and your calculations and formulas just blew right over my head. Second, it will take me a bit to grasp all of this since I am still waking up. Maybe I should have some coffee.
Let me make sure I understand this correctly. Add my STFT and LTFT to get the % value of what I need to do. In this case, 4% at idle. First value of my MAF scale is 145. 145 + 140 = 245 * .04 = 9.8. So I add 9.8 to my first value, and go down the list according to the Hz I am logging.
Will I need to do corrections at idle and cruising to get my car to drive the way it used to before the intake?
Let me make sure I understand this correctly. Add my STFT and LTFT to get the % value of what I need to do. In this case, 4% at idle. First value of my MAF scale is 145. 145 + 140 = 245 * .04 = 9.8. So I add 9.8 to my first value, and go down the list according to the Hz I am logging.
Will I need to do corrections at idle and cruising to get my car to drive the way it used to before the intake?
Wait a minute here... Why would you need to add those 2? STFT is O2 feedback, i assume its average is used to adjust LTFT's (low or mid depending on feedback @certain airflow). So wouldn't you just look at LTFT number for the percentage at corresponding Hz?
As in for idle, if you idle at 50Hz and Low LTFT is -5 you would take the number from 50Hz (152 or whatever) add 140 subtract 5% then reduce it by 140 and put it in the table.
Do the same for cruise and smooth the table.
I mean STFT bounces all over most of the time, how would you add it?
Am i missing something here?
As in for idle, if you idle at 50Hz and Low LTFT is -5 you would take the number from 50Hz (152 or whatever) add 140 subtract 5% then reduce it by 140 and put it in the table.
Do the same for cruise and smooth the table.
I mean STFT bounces all over most of the time, how would you add it?
Am i missing something here?
To really tune the entire table you have to do what l2r stated ... look at both the LTFT and the STFT. This is because the LTFT is an average based on many of the hz values. If you can hold a certain hz value the STFT will reflect how much correction is needed at that specific airflow value beyond the average LTFT.
Eric
Yeah it is... Sorry. Working the 6-3 shift all week. I guess I need more coffee or smoke some crack to wake up.
Edit for reply to Eric.
Let's say my idle Hz value is 50. My STFT and LTFT added equals -4. I take my value for 50 Hz which is 165. I add 140 and get 305 * .04 equaling 12.2. I will then subtract 12.2 from this value since the sum of my ST/LTFT was negative. If it is positive, I then add right? Or am I *** backwards?
Edit for reply to Eric.
Let's say my idle Hz value is 50. My STFT and LTFT added equals -4. I take my value for 50 Hz which is 165. I add 140 and get 305 * .04 equaling 12.2. I will then subtract 12.2 from this value since the sum of my ST/LTFT was negative. If it is positive, I then add right? Or am I *** backwards?
Last edited by pog0; Jun 10, 2008 at 08:31 AM.
When I say add the LTFT and the STFT, I state that because when you are making changes to your tune and flashing your car, resetting your battery, etc, your LTFTs may not have time to adjust to their ultimate values. To see how much % change you need, you have to add the LTFT and the STFT. The average of the STFT. If the STFT is bouncing around 0, then you aren't adding anything. But, let's say that your LTFT Lo is +5 and your STFT is bouncing around +20, because you haven't given enough time for the LTFT to change. Then, your correction is +25%.
Eric
this thread has made more since then any of the others..
If its -5, then you subtract
If its +5, then you add
Take the original value at the hz, +140 then mulitply by whatever percent, to get the giving value you need to add.
Makes since. Im going to give it a try tonight.
My LowTrim_Mid was around -4
My o2 feedback was around -20
Which would give me a total of -24 percent.
So I would take my value at 50hz which is 152+140*.24 =70.08 SUBTRACT 152 = New value of 82.
If its -5, then you subtract
If its +5, then you add
Take the original value at the hz, +140 then mulitply by whatever percent, to get the giving value you need to add.
Makes since. Im going to give it a try tonight.
My LowTrim_Mid was around -4
My o2 feedback was around -20
Which would give me a total of -24 percent.
So I would take my value at 50hz which is 152+140*.24 =70.08 SUBTRACT 152 = New value of 82.
this thread has made more since then any of the others..
If its -5, then you subtract
If its +5, then you add
Take the original value at the hz, +140 then mulitply by whatever percent, to get the giving value you need to add.
Makes since. Im going to give it a try tonight.
My LowTrim_Mid was around -4
My o2 feedback was around -20
Which would give me a total of -24 percent.
So I would take my value at 50hz which is 152+140*.24 =70.08 SUBTRACT 152 = New value of 82.
If its -5, then you subtract
If its +5, then you add
Take the original value at the hz, +140 then mulitply by whatever percent, to get the giving value you need to add.
Makes since. Im going to give it a try tonight.
My LowTrim_Mid was around -4
My o2 feedback was around -20
Which would give me a total of -24 percent.
So I would take my value at 50hz which is 152+140*.24 =70.08 SUBTRACT 152 = New value of 82.
New value is close...
-E
Log with Mitsuscanner, its values represent actual % by which the fueling is increased/decreased. So -25 will mean fueling is reduced by 25% to keep on target AFR (14.7 in most cases).
If you use Evoscan, numbers go from 0 to 200. Where 0 is -25%, 100 is 0% and 200 is +25%. So it's a bit more confusing, it's easier to use Mitsuscanner numbers.
Last edited by mplspilot; Jun 10, 2008 at 04:04 PM.
You have to log in closed loop (idle and cruise, not WOT) At WOT O2 feedback is not used by the ECU - fuel maps are used.
Log with Mitsuscanner, its values represent actual % by which the fueling is increased/decreased. So -25 will mean fueling is reduced by 25% to keep on target AFR (14.7 in most cases).
If you use Evoscan, numbers go from 0 to 200. Where 0 is -25%, 100 is 0% and 200 is +25%. So it's a bit more confusing, it's easier to use Mitsuscanner numbers.
Log with Mitsuscanner, its values represent actual % by which the fueling is increased/decreased. So -25 will mean fueling is reduced by 25% to keep on target AFR (14.7 in most cases).
If you use Evoscan, numbers go from 0 to 200. Where 0 is -25%, 100 is 0% and 200 is +25%. So it's a bit more confusing, it's easier to use Mitsuscanner numbers.
That would make since then. I only need to get the idle/low end fix. My driveablity is really good, a/fs are dead on, only thing that sucks is my tial wastegate because my maf translator isnt here.
this thread has made more since then any of the others..
If its -5, then you subtract
If its +5, then you add
Take the original value at the hz, +140 then mulitply by whatever percent, to get the giving value you need to add.
Makes since. Im going to give it a try tonight.
My LowTrim_Mid was around -4
My o2 feedback was around -20
Which would give me a total of -24 percent.
So I would take my value at 50hz which is 152+140*.24 =70.08 SUBTRACT 152 = New value of 82.
If its -5, then you subtract
If its +5, then you add
Take the original value at the hz, +140 then mulitply by whatever percent, to get the giving value you need to add.
Makes since. Im going to give it a try tonight.
My LowTrim_Mid was around -4
My o2 feedback was around -20
Which would give me a total of -24 percent.
So I would take my value at 50hz which is 152+140*.24 =70.08 SUBTRACT 152 = New value of 82.