MS3 EBC Issues
09-01-2014, 09:04 PM
#41
Retired Mech Design Engr
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[QUOTE=Rick02R;1162929
Perhaps my cold side location for the EBC solenoid is too far from the turbo? I really doubt it.
[/QUOTE]
I don't understand why you wouldn't use the compressor outlet port for the pressure source to drive the wastegate can.
DNM
Perhaps my cold side location for the EBC solenoid is too far from the turbo? I really doubt it.
[/QUOTE]
I don't understand why you wouldn't use the compressor outlet port for the pressure source to drive the wastegate can.
DNM
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09-02-2014, 08:19 AM
#43
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From the standpoint of turbulence, or boost droop? Or other?
As far a droop, I contend that it's not important in this case as we are adding EBC.
Seems to me that the highest pressure, fastest inner control loop would be ideal.
I'm open to learn.
As far a droop, I contend that it's not important in this case as we are adding EBC.
Seems to me that the highest pressure, fastest inner control loop would be ideal.
I'm open to learn.
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09-02-2014, 08:13 PM
#48
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More guess and check with PID. Possibly narrowing the scope. Seem to have decreased the amplitude of the oscillations but the periodicity is exactly the same. They don't seem to increase like they were under the old firmware.
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09-03-2014, 09:05 AM
#51
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Assume your target is 200kpa. With just the wastegate you hit 170kpa, but that tails off to 150kpa due to boost droop from the location of the WG signal.
That 200kpa has to be hit with lots more changes in EBC duty, than if you hit a relatively flat 170kpa across the board i.e. no boost droop.
Anything you can do which will make the PID loop not have to work as hard will make your life tuning the thing that much easier.
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09-03-2014, 09:40 AM
#52
Yes, and it does so by using a piece of code, and some clever maths.
Assume your target is 200kpa. With just the wastegate you hit 170kpa, but that tails off to 150kpa due to boost droop from the location of the WG signal.
That 200kpa has to be hit with lots more changes in EBC duty, than if you hit a relatively flat 170kpa across the board i.e. no boost droop.
Anything you can do which will make the PID loop not have to work as hard will make your life tuning the thing that much easier.
Assume your target is 200kpa. With just the wastegate you hit 170kpa, but that tails off to 150kpa due to boost droop from the location of the WG signal.
That 200kpa has to be hit with lots more changes in EBC duty, than if you hit a relatively flat 170kpa across the board i.e. no boost droop.
Anything you can do which will make the PID loop not have to work as hard will make your life tuning the thing that much easier.
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09-03-2014, 10:20 AM
#53
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OK, but not an additional variable, just a different one. I now understand what you are saying.
I am thinking more in terms of the longer time constant invloved with the supply at the cold side vs hot side.
For me, possibly application specific, I think the work done by the EBC solenoid and control will be much greater bringing on earlier boost, than holding boost. Also, I have boost creep, rather than droop.
Plan to certainly use the advice in this thread when I set up my EBC, just wanted to understand the driver for that fine point.
I am thinking more in terms of the longer time constant invloved with the supply at the cold side vs hot side.
For me, possibly application specific, I think the work done by the EBC solenoid and control will be much greater bringing on earlier boost, than holding boost. Also, I have boost creep, rather than droop.
Plan to certainly use the advice in this thread when I set up my EBC, just wanted to understand the driver for that fine point.
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09-04-2014, 12:04 AM
#54
Fixed my tuning laptop and I am back at it. I progressively lowered the sensitivity until I got to 50 and I was still getting some oscillation so I started at zero and started working my way up. Ended at 30 before I got home tonight. I am pretty happy with how it's holding boost steady on prolonged pulls but it seems to be overshooting quite a bit on mid throttle now. I will do more over the next couple days. Btw, I believe my sensitivity was well over 100 when I started a couple weeks ago is it's far lower than I expected it would be.
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09-04-2014, 02:55 PM
#55
Fixed my tuning laptop and I am back at it. I progressively lowered the sensitivity until I got to 50 and I was still getting some oscillation so I started at zero and started working my way up. Ended at 30 before I got home tonight. I am pretty happy with how it's holding boost steady on prolonged pulls but it seems to be overshooting quite a bit on mid throttle now. I will do more over the next couple days. Btw, I believe my sensitivity was well over 100 when I started a couple weeks ago is it's far lower than I expected it would be.
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