HOW TO - Control boost using ECUFLash and the stock boost solenoid
You need a smaller pill on the turbo side of the stock vacuum lines. It sounds like you've changed the correct one, but it may not be small enough.
The baseline boost table is used only when controlling boost based on the 3-bar map sensor. EDM models can't do this easily ... I'm not sure which model you are tuning. You'll need to adjust the boost desired engine load tables.
If you use an MBC you don't have to touch the boost tables. You'll just need to raise the boost limits.
Search "WGDC Log" for info on logging what the boost solenoid is doing.
The baseline boost table is used only when controlling boost based on the 3-bar map sensor. EDM models can't do this easily ... I'm not sure which model you are tuning. You'll need to adjust the boost desired engine load tables.
If you use an MBC you don't have to touch the boost tables. You'll just need to raise the boost limits.
Search "WGDC Log" for info on logging what the boost solenoid is doing.
Evolving Member
Joined: Jun 2008
Posts: 146
Likes: 0
From: Romania
the boost desired engine load are all set to 159.4
the 4 max. WGDC tables are set to 100%
and the wastegate offset 77.5, I have tried from 70 to 80 and 77.5 seems to produce the most stable boost, but it's still far from stable.
this evo is not EDM it's USDM, even the speedometer is in miles.
I have not installed a boost controller (I will keep that as a last solution)
I will try a pill with a smaller hole.
the 4 max. WGDC tables are set to 100%
and the wastegate offset 77.5, I have tried from 70 to 80 and 77.5 seems to produce the most stable boost, but it's still far from stable.
this evo is not EDM it's USDM, even the speedometer is in miles.
I have not installed a boost controller (I will keep that as a last solution)
I will try a pill with a smaller hole.
I'm not sure what the wastegate offset is ... maybe the boost control load offset? If so, it would have a stock value of 80. That value is added to the boost desired load table to give the desired boost/load. Increase it for more boost and lower it for less.
Now, you will also need to tune the turbo boost error correction table. This is the table that modified the solenoid duty cycle to meet the desired load set in the BDEL and BCLO tables.
You should read the ecu boost control thread ... it has a walkthrough ...
Read this - https://www.evolutionm.net/forums/sh...d.php?t=259494
then this - https://www.evolutionm.net/forums/sh...d.php?t=227006
and then do this - https://www.evolutionm.net/forums/sh...d.php?t=288408
Now, you will also need to tune the turbo boost error correction table. This is the table that modified the solenoid duty cycle to meet the desired load set in the BDEL and BCLO tables.
You should read the ecu boost control thread ... it has a walkthrough ...
Read this - https://www.evolutionm.net/forums/sh...d.php?t=259494
then this - https://www.evolutionm.net/forums/sh...d.php?t=227006
and then do this - https://www.evolutionm.net/forums/sh...d.php?t=288408
how can I raise the boost only in first 3 gears ?
Ok.
First off, you are only see 234 2byte load at 24-26psi? That seems a bit low.
Boost Desired engine load + Boost Load Offset should be at or slightly above whatever your target 2byte load is for that corrasponding RPM. Example: If your logged 2byte load at 4000 rpm is 255 then you can put in 155 in the BDEL table @ 4000 rpm and 100 in the BLO table. Or you can put 55 in the BDEL table @ 4000 rpm and 200 in the BLO table
If you have not already, I would switch your boost control to follow the current 2byte load and not the "boost load". This will make it more consistant and will also make setting your BDEL + BLO easier.
You can find information about how to do that here:
https://www.evolutionm.net/forums/sh...d.php?t=288408
That also shows you how to log base WGDC and WGDC Correction. Both make tuning the boost system much easier as you can see what is happening.
Boost limit I would recommend setting a little higher than whatever 2byte load you are hitting for that RPM. This will keep the safety feature. Currently your numbers are way too high imho.
You need to work on the boost error correction table. The first thing you need to do is take the -2 out of the 0 as this means it's going to be taking -2 out of your BWGDC whenever you are on target. I would also smooth out the negative correction and try not to use such large numbers.
If you want to take a step towards removing boost overshot and also having additive error correction in case you do hit error correction I would suggest taking a look at this thread:
https://www.evolutionm.net/forums/sh...d.php?t=333479
Specifically the "Max Total Upward WGDC Correction vs TPS" table. I personally would suggest taking the two 10's out and making them zero. This way the ecu will NEVER go above your base wastegate targets. If you do do this, you *have* to add additive error correction back into the table or your boost will never recover if it ever hits negative error correction.
First off, you are only see 234 2byte load at 24-26psi? That seems a bit low.
Boost Desired engine load + Boost Load Offset should be at or slightly above whatever your target 2byte load is for that corrasponding RPM. Example: If your logged 2byte load at 4000 rpm is 255 then you can put in 155 in the BDEL table @ 4000 rpm and 100 in the BLO table. Or you can put 55 in the BDEL table @ 4000 rpm and 200 in the BLO table
If you have not already, I would switch your boost control to follow the current 2byte load and not the "boost load". This will make it more consistant and will also make setting your BDEL + BLO easier.
You can find information about how to do that here:
https://www.evolutionm.net/forums/sh...d.php?t=288408
That also shows you how to log base WGDC and WGDC Correction. Both make tuning the boost system much easier as you can see what is happening.
Boost limit I would recommend setting a little higher than whatever 2byte load you are hitting for that RPM. This will keep the safety feature. Currently your numbers are way too high imho.
You need to work on the boost error correction table. The first thing you need to do is take the -2 out of the 0 as this means it's going to be taking -2 out of your BWGDC whenever you are on target. I would also smooth out the negative correction and try not to use such large numbers.
If you want to take a step towards removing boost overshot and also having additive error correction in case you do hit error correction I would suggest taking a look at this thread:
https://www.evolutionm.net/forums/sh...d.php?t=333479
Specifically the "Max Total Upward WGDC Correction vs TPS" table. I personally would suggest taking the two 10's out and making them zero. This way the ecu will NEVER go above your base wastegate targets. If you do do this, you *have* to add additive error correction back into the table or your boost will never recover if it ever hits negative error correction.
Evolving Member
Joined: Jun 2008
Posts: 146
Likes: 0
From: Romania
I set the boost limit higher, because I hit spikes 28psi spikes and the engine cut-off. We have tried almost the entire day to find out what caused that spike which occured only in the 3rd or 4th gear while flooring at 3000rpm, it was the forge blow-off, the valve was inverted by someone who previously "tuned" the evo.
where can I see the 2byte load ?
I don't have any other table to set the wastegate...
where can I see the 2byte load ?
I don't have any other table to set the wastegate...
Last edited by GTR2009; Jun 6, 2008 at 07:50 PM.
This method DOES work though, very stealthy.
Evolved Member
Joined: Apr 2002
Posts: 697
Likes: 1
From: Perth, Western Australia
Sorry for bringing this thread back again but having read through everything, I just want to clarify how I beleive it is working. If I am wrong please feel free to correct me.
Stock System and fundamental basics
The stock system works by running two restrictors, one between the turbo pressure source and the T-Piece which then feeds pressure to both the turbo wastegate and the bleeder valve solenoid. The Solenoid also has the second restrictor on the output side between the solenoid and the air cleaner inlet pipe.
The system works via the first restrictor "Restricting" the pressure to the system. What pressure is fed through, is then bled off via the factory controlled solenoid. Understanding that the wastegate once it reaches a a set pressure level, will start to open up and bleed boost off.
Now the second restrictor on the solenoid valves works opposite to the restrictor in the T-Piece. Its purpose is to restrict the amount of air being bled from the wastegate actuator. This increases the amount of pressure within the vacuem lines and opens the actuator sooner.
Removal of secondary restrictor on Solenoid
By removing the restrictor on the output side of the solenoid, this will increase boost slightly because the solenoid now can vent a greater volume of pressure from the vacuem lines. This reduces the pressure inside the vacuem lines, and means the wastegate actuator remains closed for longer until it reaches the set pressure to start bleeding off again. Due to the fact that this restrictor is very small, you will only acheive a 2 - 3 psi change in boost levels.
The Factory ECU Boost Software Setup
First thing to understand, is that the factory ecu / software as we are interpreting is reading in absoloute kpa. This means on the tuning maps, 0 - 100 is under vacuem, and 100 - 300 is our boost levels. I think this is where the misunderstanding comes from in the maps.
Now from my understanding we have three maps on the Factory ECU Boost control setup.
Boost Limit Map - which reads in total overall load in absoloute KPA
Boost Control Load Offset - this I beleive refers to the starting value of the waste gate duty cycle, the higher the value the more air the bleed solenoid bleeds off before starting to cycle and control boost.
Max Wastegate Duty Cycle - this refers to the duty cycle maximun value the ECU will use to cycle the bleed solenoid to control boost. At 100% this means the solenoid is fully open and bleeding off as much pressure as it can.
Boost Desired Engine Load - now from what I can see map is not reading in absoloute KPA. Instead this is referring to the boost values only. This means that where it is set to 159 (Maximun Value), it is in fact referring to 100 + 159 which is a total of 259, which equates to what most people know of as 23 psi. The +100 refers to the vacuem portions of mapping.
Turbo Boost Error Correction - this is the main map that seems to do everytying. This from what I understand, looks at what the engine / boost load is, and if it is under the desired engine load, adjusts as a plus or minus to try and alter the boost level. A positive number refers to increasing the waste gate bleeder valve duty cycle. A negative number reduces the wastegate duty cycle and increases pressure to the wastegate actuator.
Physical Modifications via the Boost Restrictor Pills
To clarify the first mod, as discussed above, removal of the secondary restrictor pill after the wastegate solenoid. This allows the solenoid to bleed off a greater volume of pressure and increase the boost level. The removal of this pill, with modifications of the primary restricotr, can induce larger boost spikes which may / may not be correctable via the software on the ECU. It appears that keeping this restrictor is not a bad idea as the majority of gains will come from modifying hte primary restrictor.
The secondary pill, as described above, its purpose is to "Restrict" the supply of pressure to the rest of the system. Essentially, removing this "Pill" and replacing with a new one with a smaller internal diameter, will mean that a greater pressure level is required before the turbo wastegate actuator can be activated. Depending upon the size of this replacement pill, you may or may not need to alter the software settings in the ECU. I would guess only marginally smaller sizes would allow boost levels to go from stockish 17 / 18 psi up to 21 - 22 psi without boost spikes or alterations. Going several sizes smaller, will definitly require alterations to the software settings.
Software alterations for large changes in the boost restrictor pill
Assuming say you have gone three sizes smaller on the boost pill and are aiming in excess of 24 psi boost levels. You would primarly need to first set the max wastegate duty cycle down to a starting values of around say, 30% and the correction factors on the turbo boost error correction to zero. You would also set the boost control load offset to around a 50 value as well. Adjust the load offset value to the point where the boost level reaches the level you want to say 25 psi. Then keep adjusting the wastegate duty cycle until the boost level level is fairly close to what you want. Finally once this is done, then adjust the turbo boost error correction maps to keep the boost level flat and stable.
Someone commented earlier that in the turbo boost error correction maps that the first four points referred to lower gears, and the last four values referred to higher gear levels. I think this is more a function of engine load where in lower gears, it can move through the rpm range faster, where in the higher gears, the vehicle moves through the rpm range slower giving the ecu more time to control the boost level via this map.
This has ended up coming through as more of an essay, but I guess its the way I think. I would welcome any comments on this, especially from long time tuners and players of EVO.
What I am still wanting to understand, is the relationship of the three different wastegate duty cycle maps and boost desired engine load maps. IF someone could clarify which one works under which conditions that would be great.
Stock System and fundamental basics
The stock system works by running two restrictors, one between the turbo pressure source and the T-Piece which then feeds pressure to both the turbo wastegate and the bleeder valve solenoid. The Solenoid also has the second restrictor on the output side between the solenoid and the air cleaner inlet pipe.
The system works via the first restrictor "Restricting" the pressure to the system. What pressure is fed through, is then bled off via the factory controlled solenoid. Understanding that the wastegate once it reaches a a set pressure level, will start to open up and bleed boost off.
Now the second restrictor on the solenoid valves works opposite to the restrictor in the T-Piece. Its purpose is to restrict the amount of air being bled from the wastegate actuator. This increases the amount of pressure within the vacuem lines and opens the actuator sooner.
Removal of secondary restrictor on Solenoid
By removing the restrictor on the output side of the solenoid, this will increase boost slightly because the solenoid now can vent a greater volume of pressure from the vacuem lines. This reduces the pressure inside the vacuem lines, and means the wastegate actuator remains closed for longer until it reaches the set pressure to start bleeding off again. Due to the fact that this restrictor is very small, you will only acheive a 2 - 3 psi change in boost levels.
The Factory ECU Boost Software Setup
First thing to understand, is that the factory ecu / software as we are interpreting is reading in absoloute kpa. This means on the tuning maps, 0 - 100 is under vacuem, and 100 - 300 is our boost levels. I think this is where the misunderstanding comes from in the maps.
Now from my understanding we have three maps on the Factory ECU Boost control setup.
Boost Limit Map - which reads in total overall load in absoloute KPA
Boost Control Load Offset - this I beleive refers to the starting value of the waste gate duty cycle, the higher the value the more air the bleed solenoid bleeds off before starting to cycle and control boost.
Max Wastegate Duty Cycle - this refers to the duty cycle maximun value the ECU will use to cycle the bleed solenoid to control boost. At 100% this means the solenoid is fully open and bleeding off as much pressure as it can.
Boost Desired Engine Load - now from what I can see map is not reading in absoloute KPA. Instead this is referring to the boost values only. This means that where it is set to 159 (Maximun Value), it is in fact referring to 100 + 159 which is a total of 259, which equates to what most people know of as 23 psi. The +100 refers to the vacuem portions of mapping.
Turbo Boost Error Correction - this is the main map that seems to do everytying. This from what I understand, looks at what the engine / boost load is, and if it is under the desired engine load, adjusts as a plus or minus to try and alter the boost level. A positive number refers to increasing the waste gate bleeder valve duty cycle. A negative number reduces the wastegate duty cycle and increases pressure to the wastegate actuator.
Physical Modifications via the Boost Restrictor Pills
To clarify the first mod, as discussed above, removal of the secondary restrictor pill after the wastegate solenoid. This allows the solenoid to bleed off a greater volume of pressure and increase the boost level. The removal of this pill, with modifications of the primary restricotr, can induce larger boost spikes which may / may not be correctable via the software on the ECU. It appears that keeping this restrictor is not a bad idea as the majority of gains will come from modifying hte primary restrictor.
The secondary pill, as described above, its purpose is to "Restrict" the supply of pressure to the rest of the system. Essentially, removing this "Pill" and replacing with a new one with a smaller internal diameter, will mean that a greater pressure level is required before the turbo wastegate actuator can be activated. Depending upon the size of this replacement pill, you may or may not need to alter the software settings in the ECU. I would guess only marginally smaller sizes would allow boost levels to go from stockish 17 / 18 psi up to 21 - 22 psi without boost spikes or alterations. Going several sizes smaller, will definitly require alterations to the software settings.
Software alterations for large changes in the boost restrictor pill
Assuming say you have gone three sizes smaller on the boost pill and are aiming in excess of 24 psi boost levels. You would primarly need to first set the max wastegate duty cycle down to a starting values of around say, 30% and the correction factors on the turbo boost error correction to zero. You would also set the boost control load offset to around a 50 value as well. Adjust the load offset value to the point where the boost level reaches the level you want to say 25 psi. Then keep adjusting the wastegate duty cycle until the boost level level is fairly close to what you want. Finally once this is done, then adjust the turbo boost error correction maps to keep the boost level flat and stable.
Someone commented earlier that in the turbo boost error correction maps that the first four points referred to lower gears, and the last four values referred to higher gear levels. I think this is more a function of engine load where in lower gears, it can move through the rpm range faster, where in the higher gears, the vehicle moves through the rpm range slower giving the ecu more time to control the boost level via this map.
This has ended up coming through as more of an essay, but I guess its the way I think. I would welcome any comments on this, especially from long time tuners and players of EVO.
What I am still wanting to understand, is the relationship of the three different wastegate duty cycle maps and boost desired engine load maps. IF someone could clarify which one works under which conditions that would be great.
Last edited by Mitsiman; Apr 24, 2009 at 06:54 AM.
