v3mafadjcombft
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v3mafadjcombft [2008/12/31 09:39] twdorris |
v3mafadjcombft [2009/02/26 14:23] twdorris |
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| ====== MAF Adj: CombinedFT ====== | ====== MAF Adj: CombinedFT ====== | ||
| + | **NOTE:** Make sure you're running the latest version of the [[v3changelog|laptop application]]. We are constantly improving and tweaking this function to get better results as more users are posting example files. | ||
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| The **MAF Adj: CombinedFT** menu item is one of several tools you can use to help "dial in" your airflow settings. This particular item maps out and averages [[v3combinedft|CombinedFT]] over a range of closed loop driving conditions to produce a set of adjustments to the current MAF compensation table. It's basically letting the ECU track how much adjustment it needs under various conditions and then moves that adjustment into the MAF compensation table. | The **MAF Adj: CombinedFT** menu item is one of several tools you can use to help "dial in" your airflow settings. This particular item maps out and averages [[v3combinedft|CombinedFT]] over a range of closed loop driving conditions to produce a set of adjustments to the current MAF compensation table. It's basically letting the ECU track how much adjustment it needs under various conditions and then moves that adjustment into the MAF compensation table. | ||
| This function probably helps most with a GM MAF setup run straight to the ECU using ECMLink's GM MAF integration option. That particular configuration produces a pretty large number of MAF sample points for fairly typical driving conditions (easily ranging from 500hz to 2000hz for simple idle and cruise conditions). So having a tool which helps establish a decent starting point can be very handy here. | This function probably helps most with a GM MAF setup run straight to the ECU using ECMLink's GM MAF integration option. That particular configuration produces a pretty large number of MAF sample points for fairly typical driving conditions (easily ranging from 500hz to 2000hz for simple idle and cruise conditions). So having a tool which helps establish a decent starting point can be very handy here. | ||
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| + | Although this function probably helps a direct GM MAF setup more, it can still be useful with other configurations too. | ||
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| A good understanding of [[v3combinedft|CombinedFT]] and [[fueltrimupdatepoints|fuel trim in general]] will help a lot with your understanding of this function. | A good understanding of [[v3combinedft|CombinedFT]] and [[fueltrimupdatepoints|fuel trim in general]] will help a lot with your understanding of this function. | ||
| - | Add the following log items to your captured values: CombinedFT, MAFRaw and ClosedLoop | + | Add the following log items to your captured values (F10): CombinedFT, MAFRaw and ClosedLoop |
| - | Make sure the engine is at full operating temperatures. You don't want to mess with coolant based various at this point. You want to stabilize everything you can first and then adjust based on the one variable left (presumably airflow variation). | + | Make sure the engine is at full operating temperatures. You don't want to mess with coolant based variations at this point. You want to stabilize everything you can first and then adjust based on the one variable left (presumably airflow variation). |
| ===== Basic Usage ===== | ===== Basic Usage ===== | ||
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| With that table in place, you can grab a datalog with a bit more load variation. Personally, I like to find a nice hilly area and apply light throttle to vary LoadFactor between 0.9 to 1.3 while maintaining closed loop operation. This driving combined with the typical flat road driving (with LoadFactors around 0.6-0.9), combined with typical idle and free rev (LoadFactors around 0.3-0.4) really produces a good set of data for this function. | With that table in place, you can grab a datalog with a bit more load variation. Personally, I like to find a nice hilly area and apply light throttle to vary LoadFactor between 0.9 to 1.3 while maintaining closed loop operation. This driving combined with the typical flat road driving (with LoadFactors around 0.6-0.9), combined with typical idle and free rev (LoadFactors around 0.3-0.4) really produces a good set of data for this function. | ||
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| I'll walk through a sample calibration of my own car below. This is a 1995 AWD Talon with 850 injectors running E85 and a GM 3" MAF connected to the ECU. The MAF is installed just before the throttle body using upper IC piping that has flared 3" ends as shown below. | I'll walk through a sample calibration of my own car below. This is a 1995 AWD Talon with 850 injectors running E85 and a GM 3" MAF connected to the ECU. The MAF is installed just before the throttle body using upper IC piping that has flared 3" ends as shown below. | ||
| - | << insert picture when I finally remember to bring the //@$!%$!$// memory card in >> | + | {{ http://www.ecmtuning.com/images/forums/gmmafinstall.jpg }} |
| Download the datalog below to review the initial drive cycle (20 minutes or so) and setup. The things to note include the global fuel setting and the MAF compensation. | Download the datalog below to review the initial drive cycle (20 minutes or so) and setup. The things to note include the global fuel setting and the MAF compensation. | ||
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| I'm also going to extend the lowest adjustment point to cover the areas where I was not able to collect any data. My car idles around 600hz with the GM 3" MAF. So it's hard to produce much closed loop data below this point. So we're going to assume it's somewhere around the 600hz point just in case the car ever does end up below that point. | I'm also going to extend the lowest adjustment point to cover the areas where I was not able to collect any data. My car idles around 600hz with the GM 3" MAF. So it's hard to produce much closed loop data below this point. So we're going to assume it's somewhere around the 600hz point just in case the car ever does end up below that point. | ||
| - | Looking at the 1700 and 1800hz points, I feel a need to tweak them a bit. They're just flat where as the points before and after are not. So I'm going to slightly adjust those two points between so that they make a more natural transition between the 1600 and 1900 points. After doing that, you can see the new results below. | + | Looking at the 1700 and 1800hz points, I feel a need to tweak them a bit. They're just flat where as the points before and after are not. So I'm going to slightly adjust those two points so that they make a more natural transition between the 1600 and 1900 points. After doing that, you can see the new results below. |
| {{ http://www.ecmtuning.com/images/forums/mafadjcombft/resultsmod1.png }} | {{ http://www.ecmtuning.com/images/forums/mafadjcombft/resultsmod1.png }} | ||
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| {{ http://www.ecmtuning.com/images/forums/mafadjcombft/resultsfinal.png }} | {{ http://www.ecmtuning.com/images/forums/mafadjcombft/resultsfinal.png }} | ||
| - | This is my new, final configuration. I'll do an "ECU->Reset fuel trims" next and go drive. Everything should line up much better now. | + | This is my new, final configuration. To get that centered nicely, I'll click the "Change..." button next to "Global scalar" field and then click "Auto Adj" on the dialog that pops up. The application will center the current set of adjustments for me and produce an appropriate global scalar value. I'll then do an "ECU->Reset fuel trims" and go drive. Everything should line up much better now. |
v3mafadjcombft.txt ยท Last modified: 2024/03/15 11:16 (external edit)
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