Tutorial: How to scale your MAF [pics]
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Tutorial: How to scale your MAF [pics]
Credit goes to l2r99gst for fingering this out. I really don't know a ton about this, so hopefully other people can chime in for questions.
This is a step-by-step of how to change the scaling for your MAF.
This doesn't affect your map. It affects the way ecuflash reads your map and how you interpret it. Once you change this, it will apply to all maps that you load with ecuflash.
Step 1: Load up ecuflash and right click on MAF scaling. Select "edit map"
Step 2: Here is what the finished table should look like. Circled in red are the important things. Click on the "Scalings..." button to add your custom scale.
Step 3: Click on the "add" button to create a new custom scale
Step 4: Here is a pic of what comes up. This is the screen that you will edit to make your new scale.
Step 5: Enter in the values that I've circled in red. Click "ok"
Step 6: Now you're back at the "edit table" screen. Make sure that the Y axis load scaling points to the scale that you just created. Use the dropdown menu to select it.
Finished: Your old scale and your new scale. Old one begins with 192. New one begins with 19.
Here is an example of how you actually put it into action.
Step 1: First you need to datalog your short term and long term fuel trims at a given MAF reading. This tells you how far "off" you are. So if your trims are +10%, that means you need to scale the MAF by 10%. The reading can be in Hz, lb/min, L/min, L/sec etc. Ultimately we want to end up reading MAF in Hz because that is what we just scaled ecuflash to. I've included a chart which can get you a rough idea of how to convert to Hz.
Here is a shot of what I logged with my OBDII scanner. Notice the long term fuel trim, short term fuel trim, and I have my choice of reading my MAF in lb/min or g/s. My OBDII scanner gives both these values. Yours might give a different one.
Here is a nice chart provided by l2r99gst that will help you convert whatever unit you are reading MAF to Hz used by ecuflash. For the example, you can see that with my OBDII log above, that I will use either lb/min or g/s to find the corresponding Hz value that ecuflash uses.
So...here is how you find out just how "off" you really are.
You add your long term trim and your short term trim together for any given MAF value. Here you see 12.5 + 10.9 when my MAF reads 0.327lb/min
I need to find out where my 0.327lb/min falls on the ecuflash map so I look at this chart. I find my lb/min value. It's very close to the one given on the chart. I look over to my right to see what value ecuflash has associated with that row. It's 18.75 (actually 19 because ecuflash rounded up)
Another example: If I were datalogging and found my MAF value to be 4.00 lb/min I would look at this chart and know that I would need to adjust the 200 Hz value in ecuflash.
So now that I know i'm working with the 19 cell...here is how I actually calculate the changes that I need to make in order to scale.
My long term trim + my short term trim = 23%.
I need to add 23% to my MAF scale.
At the 19 cell, the factory value is 145.
There is an 'adder' value that is used so always add 140 to the factory value.
145+ 140 = 285.
I want to add 23% of 285.
285 * 0.23 = 65.55
145(my original value) + 65.55 = 210.55
210.55 is my new value.
Here it is changed in the MAF scaling map.
This is a step-by-step of how to change the scaling for your MAF.
This doesn't affect your map. It affects the way ecuflash reads your map and how you interpret it. Once you change this, it will apply to all maps that you load with ecuflash.
Step 1: Load up ecuflash and right click on MAF scaling. Select "edit map"
Step 2: Here is what the finished table should look like. Circled in red are the important things. Click on the "Scalings..." button to add your custom scale.
Step 3: Click on the "add" button to create a new custom scale
Step 4: Here is a pic of what comes up. This is the screen that you will edit to make your new scale.
Step 5: Enter in the values that I've circled in red. Click "ok"
Step 6: Now you're back at the "edit table" screen. Make sure that the Y axis load scaling points to the scale that you just created. Use the dropdown menu to select it.
Finished: Your old scale and your new scale. Old one begins with 192. New one begins with 19.
Here is an example of how you actually put it into action.
Step 1: First you need to datalog your short term and long term fuel trims at a given MAF reading. This tells you how far "off" you are. So if your trims are +10%, that means you need to scale the MAF by 10%. The reading can be in Hz, lb/min, L/min, L/sec etc. Ultimately we want to end up reading MAF in Hz because that is what we just scaled ecuflash to. I've included a chart which can get you a rough idea of how to convert to Hz.
Here is a shot of what I logged with my OBDII scanner. Notice the long term fuel trim, short term fuel trim, and I have my choice of reading my MAF in lb/min or g/s. My OBDII scanner gives both these values. Yours might give a different one.
Here is a nice chart provided by l2r99gst that will help you convert whatever unit you are reading MAF to Hz used by ecuflash. For the example, you can see that with my OBDII log above, that I will use either lb/min or g/s to find the corresponding Hz value that ecuflash uses.
So...here is how you find out just how "off" you really are.
You add your long term trim and your short term trim together for any given MAF value. Here you see 12.5 + 10.9 when my MAF reads 0.327lb/min
I need to find out where my 0.327lb/min falls on the ecuflash map so I look at this chart. I find my lb/min value. It's very close to the one given on the chart. I look over to my right to see what value ecuflash has associated with that row. It's 18.75 (actually 19 because ecuflash rounded up)
Another example: If I were datalogging and found my MAF value to be 4.00 lb/min I would look at this chart and know that I would need to adjust the 200 Hz value in ecuflash.
So now that I know i'm working with the 19 cell...here is how I actually calculate the changes that I need to make in order to scale.
My long term trim + my short term trim = 23%.
I need to add 23% to my MAF scale.
At the 19 cell, the factory value is 145.
There is an 'adder' value that is used so always add 140 to the factory value.
145+ 140 = 285.
I want to add 23% of 285.
285 * 0.23 = 65.55
145(my original value) + 65.55 = 210.55
210.55 is my new value.
Here it is changed in the MAF scaling map.
Last edited by SophieSleeps; Feb 4, 2007 at 09:54 PM.
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If it thinks it's getting a pint-size cup of air but actually is getting buckets of air...you will want to change that. The car uses fuel trims to adjust for things like this, but you can go outside the range of your trimming capability. The ultimate goal of this is to get your fuel trims a close to 0 as possible.
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All this changes is how much air the MAF sensor thinks is passing through it.
At idle, does it think that a little is passing through...or did you put on an intake and now a ton is passing through it. Well, if you put on an intake and significantly changed the airflow, you'll have to re-scale the MAF sensor so that it reads the correct amount of air.
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I am still trying to correct them. I started this last night.
I successfully changed the scale. That was easy.
My long term fuel trims are now at 0 so that is definately a start. Before they were pretty high.
Here is how I convert my lb/min to Hz.
I created a table in excel and did a "lookup" on that table.
I successfully changed the scale. That was easy.
My long term fuel trims are now at 0 so that is definately a start. Before they were pretty high.
Here is how I convert my lb/min to Hz.
I created a table in excel and did a "lookup" on that table.
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It is only for closed loop tuning. It doesn't affect open loop.
All this changes is how much air the MAF sensor thinks is passing through it.
At idle, does it think that a little is passing through...or did you put on an intake and now a ton is passing through it. Well, if you put on an intake and significantly changed the airflow, you'll have to re-scale the MAF sensor so that it reads the correct amount of air.
All this changes is how much air the MAF sensor thinks is passing through it.
At idle, does it think that a little is passing through...or did you put on an intake and now a ton is passing through it. Well, if you put on an intake and significantly changed the airflow, you'll have to re-scale the MAF sensor so that it reads the correct amount of air.
The reason you may want to change this table is because a modification like a cone filter or an intake pipe may alter the airflow past the sensor's measuring area, either bypassing more around it or passing more through it. You basically want to recalibrate the setup so that you are getting an accurate airflow value.
Eric
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This affects closed and open loop. This table is basically the calibration for your MAF and the stock intake setup (airbox, pipe, etc). The ECU uses it to translate a Hz value into a mass airflow so that an IPW can be calculated.
The reason you may want to change this table is because a modification like a cone filter or an intake pipe may alter the airflow past the sensor's measuring area, either bypassing more around it or passing more through it. You basically want to recalibrate the setup so that you are getting an accurate airflow value.
Eric
The reason you may want to change this table is because a modification like a cone filter or an intake pipe may alter the airflow past the sensor's measuring area, either bypassing more around it or passing more through it. You basically want to recalibrate the setup so that you are getting an accurate airflow value.
Eric
I was thinking about tuning idle...but this is related to my question about re-scaling the entire map with a given percentage...but whatever. I just rescaled the first few values so my open loop tuning wouldn't be affected. I have my AFR's perfect and don't want to f with it.
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my stock 03 maf scaling looks quite a bit different than yours (Evo IX) sophiesleeps. I start at 182 and to 291. If I could figure out how to do a screen shot, I'd post it here, but damnit...... I haven't figured out how to do it.
Regardless, I used your formula to rescale the lower Hz cells to clear up some light load issues I'm having, and yes, it does have a definite impact on a/f's and driveability. I started out using a small step change, only 1/2 of what your formula recommended, if I used the full amount of correction, it was just to big of a step change for me to be comfortable with. Either way, the 1/2 adjustment had a noticeable impact, in the right direction. I plan on playing with it more tomorrow.
Thanks for posting this tutorial.
Regardless, I used your formula to rescale the lower Hz cells to clear up some light load issues I'm having, and yes, it does have a definite impact on a/f's and driveability. I started out using a small step change, only 1/2 of what your formula recommended, if I used the full amount of correction, it was just to big of a step change for me to be comfortable with. Either way, the 1/2 adjustment had a noticeable impact, in the right direction. I plan on playing with it more tomorrow.
Thanks for posting this tutorial.
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my stock 03 maf scaling looks quite a bit different than yours (Evo IX) sophiesleeps. I start at 182 and to 291. If I could figure out how to do a screen shot, I'd post it here, but damnit...... I haven't figured out how to do it.
Regardless, I used your formula to rescale the lower Hz cells to clear up some light load issues I'm having, and yes, it does have a definite impact on a/f's and driveability. I started out using a small step change, only 1/2 of what your formula recommended, if I used the full amount of correction, it was just to big of a step change for me to be comfortable with. Either way, the 1/2 adjustment had a noticeable impact, in the right direction. I plan on playing with it more tomorrow.
Thanks for posting this tutorial.
Regardless, I used your formula to rescale the lower Hz cells to clear up some light load issues I'm having, and yes, it does have a definite impact on a/f's and driveability. I started out using a small step change, only 1/2 of what your formula recommended, if I used the full amount of correction, it was just to big of a step change for me to be comfortable with. Either way, the 1/2 adjustment had a noticeable impact, in the right direction. I plan on playing with it more tomorrow.
Thanks for posting this tutorial.
I did the same thing.
Then I just laid my ***** on the floor and went with my "formula" if you want to call it that.
Credit shouldn't go to me. It should go to the dude who fingered this stuff out. I can never remember his SN.