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bcssetup [2014/01/14 05:45]
twdorris [Confirm that you have control]
bcssetup [2015/10/23 10:16] (current)
dmertz [Setting up the Boost Target table baseline]
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 ==== Setting up the Boost Target table baseline ==== ==== Setting up the Boost Target table baseline ====
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 === Explanation === === Explanation ===
  
-This step is **very** important to get a good baseline for error correction.  ​ 
  
-Once you have the base duty cycle table set up, you'll want to start with a good Boost Target table that mimics what the turbo actually does.  This is particularly important in off boost areas where the turbo just can't build full boost. ​ Setting a boost target too high in this area *will* result in over shoot after you enable error correction because the error correction logic will ramp up the duty cycle trying to achieve a boost target that the turbo just can't do.+This step is **very** important to get a good baseline for error correction. 
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 +Once you have the base duty cycle table set up, you'll want to start with a good Boost Target table that mimics what the turbo actually does. This is particularly important in off boost areas where the turbo just can't build full boost. Setting a boost target too high in this area *will* result in over shoot after you enable error correction because the error correction logic will ramp up the duty cycle trying to achieve a boost target that the turbo just can'​t ​do. 
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 +So once you get into an area where the turbo **can** build boost, you'll already have elevated duty cycle values and the boost pressure will over shoot before error correction has a chance to drop the duty cycles back down. This can also result in oscillation as the error correction logic tries to fix itself in both directions. 
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 +So you can see it's very important to start with a Boost Target table that has an accurate representation of what the turbo can actually ​do.
  
-So once you get into an area where the turbo **can** build boost, you'll already have elevated duty cycle values and the boost pressure will over shoot before error correction has a chance to drop the duty cycles back down.  This can also result in oscillation as the error correction logic tries to fix itself in both directions. 
  
-So you can see it's very important to start with a Boost Target table that has an accurate representation of what the turbo can actually do.  ​ 
 === Collecting some data === === Collecting some data ===
  
-You can get a good Boost Target starting point by making a long 1st, 2nd and 3rd gear pull with error correction disabled and starting at an RPM below where the turbo can build boost. ​ So start at, say, 2000-2500 RPM on a flat road in each gear and take it out to, say, 7000-7500 RPM at full throttle. ​ Repeat for each gear and maybe do a couple pulls like that.   You want as much data as you can get. 
  
 +You can get a good Boost Target starting point by making a long 1st, 2nd and 3rd gear pull with error correction disabled and starting at an RPM below where the turbo can build boost. So start at, say, 2000-2500 RPM on a flat road in each gear and take it out to, say, 7000-7500 RPM at full throttle (//​ThrotPos//​ must be above 90%). Repeat for each gear and maybe do a couple pulls like that. You want as much data as you can get.
 === Use the Set Boost (WGS) tables helper function === === Use the Set Boost (WGS) tables helper function ===
  
-With that datalog displayed, right click on the graph and select the "Set Boost (WGS) tables"​ helper function. ​ This function averages the boost pressure and duty cycle at each RPM point and in each gear found in the current datalog and copies that data into the Boost (WGS) tab.+ 
 +With that datalog displayed, right click on the graph and select the "Set Boost (WGS) tables"​ helper function. This function averages the boost pressure and duty cycle at each RPM point and in each gear found in the current datalog and copies that data into the Boost (WGS) tab. 
  
 When you do this with "​good"​ data, you'll find a table similar to the following: When you do this with "​good"​ data, you'll find a table similar to the following:
  
-{{  http://​www.ecmtuning.com/​wiki/​_media/​boosttarget.png ​ }} 
  
-Note how each gear builds full boost at different areas of the RPM band.  And notice how this particular example shows some boost spike just as full boost is built You can either keep that spike in the curve or try to dial it out using lower duty cycle values and lower boost target values I personally like this spike, so I run it that way on purpose.  ​I want to get as  much as I can from my turbo. ​ So building more boost early on in the RPM band (where my turbo actually can build boost) is one way to do that.+{{  http://www.ecmtuning.com/​wiki/​_media/​boosttarget.png?​direct& ​ }} 
  
 +Note how each gear builds full boost at different areas of the RPM band. And notice how this particular example shows some boost spike just as full boost is built. You can either keep that spike in the curve or try to dial it out using lower duty cycle values and lower boost target values. I personally like this spike, so I run it that way on purpose. I want to get as much as I can from my turbo. So building more boost early on in the RPM band (where my turbo actually can build boost) is one way to do that.
  
 ==== Fine tuning with error correction enabled ==== ==== Fine tuning with error correction enabled ====
bcssetup.txt · Last modified: 2015/10/23 10:16 by dmertz