WGDC is actually what is controling/building boost?
#1
WGDC is actually what is controling/building boost?
Just for reference, haven't found this adaptation, interpretation, or suggestion any where in here, so assuming it hasn't been asked. Maybe I am just the slow guy that is not puting 2 & 2 together either .
Tuning question. I'm in the sweet spot of tuning, adjusting boost/AFR for unadulterated power! Is it the WGDC that actually builds and controls boost?
Yes you set your basline boost, or desired load, but, is it the WGDC that actually spools, and controls the boost?
Reason for my question, I changed my curve ever so slightly on my WGDC, and now I am only maxing at 21 slightly under 22 psi, from 23+ just shy 24 psi this morning. I only adjusted the curve of my wastegate.
I am on MFFRED's 94170015 ECU Based Boost control. I am only throwing it out there as a question to if my hunch is correct?
Thanks so much for taking the time to answer what I am sure is fundamental tuning knowledge.
Edit: While were on the topic, is there such a thing as to tight of control when it comes to the relation of the "Desired Load", "Baseline Boost", to the WGDC Tables. I have a smooth curve in both, but also have them set pretty tight as well. Having the WGDC to high will cause it to overboost or can you get it to be on like that. I might not be making this comprehendable... I want my guage and logs to be pretty stable and have a nice generally flat boost output/taper. 2psi of slope. Maybe even 1. But I want to know that if my WG is what drives the boosts, then why in most stock maps and tuned maps, do you see some weird stuff with WGDC. Stock maps are 100% all the way. All my tuned maps have a dip. I guess this part could have been in the ECU based thread, but its here and part of the question.
Thanks again.
Tuning question. I'm in the sweet spot of tuning, adjusting boost/AFR for unadulterated power! Is it the WGDC that actually builds and controls boost?
Yes you set your basline boost, or desired load, but, is it the WGDC that actually spools, and controls the boost?
Reason for my question, I changed my curve ever so slightly on my WGDC, and now I am only maxing at 21 slightly under 22 psi, from 23+ just shy 24 psi this morning. I only adjusted the curve of my wastegate.
I am on MFFRED's 94170015 ECU Based Boost control. I am only throwing it out there as a question to if my hunch is correct?
Thanks so much for taking the time to answer what I am sure is fundamental tuning knowledge.
Edit: While were on the topic, is there such a thing as to tight of control when it comes to the relation of the "Desired Load", "Baseline Boost", to the WGDC Tables. I have a smooth curve in both, but also have them set pretty tight as well. Having the WGDC to high will cause it to overboost or can you get it to be on like that. I might not be making this comprehendable... I want my guage and logs to be pretty stable and have a nice generally flat boost output/taper. 2psi of slope. Maybe even 1. But I want to know that if my WG is what drives the boosts, then why in most stock maps and tuned maps, do you see some weird stuff with WGDC. Stock maps are 100% all the way. All my tuned maps have a dip. I guess this part could have been in the ECU based thread, but its here and part of the question.
Thanks again.
Last edited by Raceghost; Sep 10, 2009 at 10:50 PM.
#2
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You got it right.
WGDC controls your boost level. Boost Desired Load is what it says, desired. So your ecu will adjust WGDC to whatever it needs to in order to get to that desired level.
What many people try to do is set the WGDC values first then figure out what load that creates then set your desired load to those values. Then theoretically your ECU won't have to do any adjustments.
About your other question - people making weird WGDC curves - you can discover for yourself that is what is required to get the type of boost curve you want.
As you get to higher RPM you have more exhaust flowing so it will overpower the wastegate, increasing WGDC will fight back against that to a certain degree.
WGDC controls your boost level. Boost Desired Load is what it says, desired. So your ecu will adjust WGDC to whatever it needs to in order to get to that desired level.
What many people try to do is set the WGDC values first then figure out what load that creates then set your desired load to those values. Then theoretically your ECU won't have to do any adjustments.
About your other question - people making weird WGDC curves - you can discover for yourself that is what is required to get the type of boost curve you want.
As you get to higher RPM you have more exhaust flowing so it will overpower the wastegate, increasing WGDC will fight back against that to a certain degree.
#3
Evolved Member
iTrader: (17)
Here I copied this from my How-to on controlling boost with the ECU.
Step 19 - Tuning
The following maps will need to be changed for basic boost control
Max WGDG/Basline WGDC (NOTE: map will be titled MAX WGDC or Baseline WGDC, based on what definitions your using. They are the same map.)
Boost Desired Engine Load
Boost Control Load Offset
Turbo Boost Error Correction
Boost Limit - This is the famous "Boost/fuel Cut". Set this about 20 higher then your max load.
PROCESS
***When taking the car out for the first test drive, roll on to boost SLOWLY and constantly monitor boost. If it starts to boost more then a safe amount for your octane and tune, LET OFF THE GAS.
Zero out the right side of the "Turbo Boost Error Correction" map. (keep a copy of the stock settings somewhere)
Then use the "Max WGDG/Basline WGDC" to get your desired boost curve in 3rd gear.
**Here is an example
RPM - WG duty
2000 - 70
2500 - 60
3000 - 50
3500 - 50
4000 - 50
4500 - 50
5000 - 55
5500 - 55
6000 - 60
6500 - 65
7000 - 70
After you have your desired boost curve, log your load (preferable 2byte load) in 3rd gear from 2500-7500RPM.
Set "Boost Control Load Offset" and the "Boost Desired Engine Load" so when they are added together, they add up to the load in your log (@ the same RPM point). ie if you logged 240 load @ 3500RPM, then the "Boost Control Load Offset" would be 100 and the "Boost Desired Engine Load" to be 140 @ 3500RPM.
After you have your "Boost Desired Engine Load" completely filled out, using your logs for load amounts, then re-enter the stock setting on the right side of the "Turbo Boost Error Correction" map (Stock setting can work, but you may have to tune this map)
It will take some tuning to get everything perfect. Log Load, boost, WGDC, Load Error and WGDC Correction and make correction based on those.
Also, here is a great description on how the error correction work. Thanks mrfred
*BDEL=Boost Desired Engine Load
Step 19 - Tuning
The following maps will need to be changed for basic boost control
Max WGDG/Basline WGDC (NOTE: map will be titled MAX WGDC or Baseline WGDC, based on what definitions your using. They are the same map.)
Boost Desired Engine Load
Boost Control Load Offset
Turbo Boost Error Correction
Boost Limit - This is the famous "Boost/fuel Cut". Set this about 20 higher then your max load.
PROCESS
***When taking the car out for the first test drive, roll on to boost SLOWLY and constantly monitor boost. If it starts to boost more then a safe amount for your octane and tune, LET OFF THE GAS.
Zero out the right side of the "Turbo Boost Error Correction" map. (keep a copy of the stock settings somewhere)
Then use the "Max WGDG/Basline WGDC" to get your desired boost curve in 3rd gear.
**Here is an example
RPM - WG duty
2000 - 70
2500 - 60
3000 - 50
3500 - 50
4000 - 50
4500 - 50
5000 - 55
5500 - 55
6000 - 60
6500 - 65
7000 - 70
After you have your desired boost curve, log your load (preferable 2byte load) in 3rd gear from 2500-7500RPM.
Set "Boost Control Load Offset" and the "Boost Desired Engine Load" so when they are added together, they add up to the load in your log (@ the same RPM point). ie if you logged 240 load @ 3500RPM, then the "Boost Control Load Offset" would be 100 and the "Boost Desired Engine Load" to be 140 @ 3500RPM.
After you have your "Boost Desired Engine Load" completely filled out, using your logs for load amounts, then re-enter the stock setting on the right side of the "Turbo Boost Error Correction" map (Stock setting can work, but you may have to tune this map)
It will take some tuning to get everything perfect. Log Load, boost, WGDC, Load Error and WGDC Correction and make correction based on those.
Also, here is a great description on how the error correction work. Thanks mrfred
*BDEL=Boost Desired Engine Load
The "Max WGDC" table is poorly named. It should be called "Baseline WGDC" table. When you are cruising, the car is at 0% WGDC (at least that's what EvoScan says), and when you stomp on the gas, the ECU looks at the engine RPM, then goes to the Baseline WGDC table, reads the WGDC number, and applies that value to the BCS. At that point, the ECU then starts comparing the actual load to the target load (BDEL + boost offset) about once every 0.4 seconds. If the actual load matches the target load, then the ECU continues to follow the WGDC value (vs RPM) in the baseline WGDC table. However, if the ECU sees a discrepancy between actual and target load, then it can/will apply a correction to the WGDC. The amount of correction depends on the values in the boost error correction table. The correction is simply to raise or lower the entire Baseline WGDC curve. So after the correction is applied, the ECU follows the raised/lowered curve. It checks again 0.4 seconds later, and if necessary, raises or lowers the curve again. This is why the correction table isn't a function of RPM. The graph shows the behavior well. The blue arrows show when corrections are made, and its apparent that the ECU is simply raising/lowering the baseline WGDC curve.
#5
EvoM Community Team
iTrader: (15)
Maybe you need to understand the acronym....
WGDC = WasteGate Duty Cycle
This is the amount of time that the solenoid is bleeding air from the wastegate. Since air pressure opens the wastegate, the more time per unit of time that you are bleeding air from it, the less / later the wastegate will open, the more the turbo will spool, and the more boost you will get.
As roger said, the other tables set your desired or "ideal" boost. Since the system is "dumb" and can only react as you tell it, you can set them "too tight", but I wouldn't call it that. It would be better described as "unattainable" which the dumb system will over-correct to "not what you want this instant" aka overboost.
Kind of right. It is more that the stock solenoid can't bleed off more than a certain percent (below 100) because it is only a two port. Without pills, it could only bleed 50% of the air in the most ideal situation (if both lines were the same size/length). The pills alow this value to be raised, but it can never reach 100% because it can never completely interrupt flow to the wastegate.
It can aim for 100% wastegate duty cycle and adjust from there because the system is reasonably slow to raise boost to unsafe levels. WGDC is still in effect, but the target can be higher because of the inefficiency of the system.
WGDC = WasteGate Duty Cycle
This is the amount of time that the solenoid is bleeding air from the wastegate. Since air pressure opens the wastegate, the more time per unit of time that you are bleeding air from it, the less / later the wastegate will open, the more the turbo will spool, and the more boost you will get.
As roger said, the other tables set your desired or "ideal" boost. Since the system is "dumb" and can only react as you tell it, you can set them "too tight", but I wouldn't call it that. It would be better described as "unattainable" which the dumb system will over-correct to "not what you want this instant" aka overboost.
It can aim for 100% wastegate duty cycle and adjust from there because the system is reasonably slow to raise boost to unsafe levels. WGDC is still in effect, but the target can be higher because of the inefficiency of the system.
Last edited by fostytou; Sep 11, 2009 at 02:14 PM.
#6
Evolved Member
iTrader: (17)
Maybe you need to understand the acronym....
WGDC = WasteGate Duty Cycle
This is the amount of time that the solenoid is bleeding air from the wastegate. Since air pressure opens the wastegate, the more time per unit of time that you are bleeding air from it, the less / later the wastegate will open, the more the turbo will spool, and the more boost you will get.
As roger said, the other tables set your desired or "ideal" boost. Since the system is "dumb" and can only react as you tell it, you can set them "too tight", but I wouldn't call it that. It would be better described as "unattainable" which the dumb system will over-correct to "not what you want this instant" aka overboost.
Kind of right. It is more that the stock solenoid can't bleed off more than a certain percent (below 100) because it is only a two port. Without pills, it could only bleed 50% of the air in the most ideal situation (if both lines were the same size/length). The pills alow this value to be raised, but it can never reach 100% because it can never completely interrupt flow to the wastegate.
WGDC = WasteGate Duty Cycle
This is the amount of time that the solenoid is bleeding air from the wastegate. Since air pressure opens the wastegate, the more time per unit of time that you are bleeding air from it, the less / later the wastegate will open, the more the turbo will spool, and the more boost you will get.
As roger said, the other tables set your desired or "ideal" boost. Since the system is "dumb" and can only react as you tell it, you can set them "too tight", but I wouldn't call it that. It would be better described as "unattainable" which the dumb system will over-correct to "not what you want this instant" aka overboost.
Kind of right. It is more that the stock solenoid can't bleed off more than a certain percent (below 100) because it is only a two port. Without pills, it could only bleed 50% of the air in the most ideal situation (if both lines were the same size/length). The pills alow this value to be raised, but it can never reach 100% because it can never completely interrupt flow to the wastegate.
I just though maybe you didnt know who your were talking to or something.
Also, what you quoted my saying, I just said it in the most basic way possiable.
Last edited by Evo_Jay; Sep 11, 2009 at 02:20 PM.
#7
Guys, thank you for taking the time to explain this to me.
Yes, I understand the acronym, I used it wrong. I was leading towards it is that table that you adjust the WG to spool or control the bleedoff of actual exhaust. Thank you kindly again.
I was just making sure I was on the right page. The solenoid is the hammer, and the WG is the nail. The nail is what actually holds the board. Ok, now that I am squared away.
Thank you EVO Kid for that awsome write up, did not meen to bypass your experties in referencing MFRED's ECU based boost control or PSI based. All my tables read in PSI now...
Thanks again guys.
WGDC = WasteGate Duty Cycle
I was just making sure I was on the right page. The solenoid is the hammer, and the WG is the nail. The nail is what actually holds the board. Ok, now that I am squared away.
Thank you EVO Kid for that awsome write up, did not meen to bypass your experties in referencing MFRED's ECU based boost control or PSI based. All my tables read in PSI now...
Thanks again guys.
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#8
Evolved Member
iTrader: (17)
Guys, thank you for taking the time to explain this to me.
Yes, I understand the acronym, I used it wrong. I was leading towards it is that table that you adjust the WG to spool or control the bleedoff of actual exhaust. Thank you kindly again.
I was just making sure I was on the right page. The solenoid is the hammer, and the WG is the nail. The nail is what actually holds the board. Ok, now that I am squared away.
Thank you EVO Kid for that awsome write up, did not meen to bypass your experties in referencing MFRED's ECU based boost control or PSI based. All my tables read in PSI now...
Thanks again guys.
Yes, I understand the acronym, I used it wrong. I was leading towards it is that table that you adjust the WG to spool or control the bleedoff of actual exhaust. Thank you kindly again.
I was just making sure I was on the right page. The solenoid is the hammer, and the WG is the nail. The nail is what actually holds the board. Ok, now that I am squared away.
Thank you EVO Kid for that awsome write up, did not meen to bypass your experties in referencing MFRED's ECU based boost control or PSI based. All my tables read in PSI now...
Thanks again guys.
Also, even with psi based boost control, the theory is still that same, just theres the boost adder, instead of load offset, and theres desired boost, instead of desired load, etc.
#9
EvoM Community Team
iTrader: (15)
Not trying to be rude, but you know I wrote the How-to's for controlling boost with the stock ECU and figured out how the stock load boost system works, right??
I just though maybe you didnt know who your were talking to or something.
Also, what you quoted my saying, I just said it in the most basic way possiable.
I just though maybe you didnt know who your were talking to or something.
Also, what you quoted my saying, I just said it in the most basic way possiable.
You are bleeding off the exhuast with the wastegate before it gets through the turbine and pushes the blades. Send air to wastegate, push rod/actuator, bleed gas before it pushes turbine.
Last edited by fostytou; Sep 11, 2009 at 07:49 PM.
#10
Evolved Member
iTrader: (17)
Chill dude. I was agreeing with you and elaborating. I could definitely see what you wrote being taken by someone a few different incorrect ways. Just trying to make sure everyone is on the same page.
Sry. I guess I just took it differently.
You are bleeding off the exhuast with the wastegate before it gets through the turbine and pushes the blades. Send air to wastegate, push rod/actuator, bleed gas before it pushes turbine.
Sry. I guess I just took it differently.
You are bleeding off the exhuast with the wastegate before it gets through the turbine and pushes the blades. Send air to wastegate, push rod/actuator, bleed gas before it pushes turbine.
#11
Evolved Member
iTrader: (2)
You can think of it this way. With the stock setup it is very difficult to increase boost becase the pill only let bleed certain air even at 100% WGDC (like a bleeder controller). But it does a good job in lowering boost in an overboost condition (by shutting the valve). So it was an easy decision to Mitsubishi if you look at in in terms of warranty .
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