Boost PID=200,0,0 - still hits boost limit
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Here is my problem. I have been running in closed loop for the past several weeks but since my boost was not tailored to this car, I decided to tune my PID settings. The boost hadn't been steady to my satisfaction and I figured it was time to start fine tuning.
To start with, I switched over to open-loop and set the entire table to 100 and did a pull. I immediately hit boost limit. I then switched the polarity to inverse and tried again. Now I was essentially on wastegate. I then set my P to 100, I to zero, and D to zero. I did a pull. almost immediately I hit my boost limit of 175kpa. I upped my P to 150. Same thing. Finally to 200, and same result. What could be causing me to immediately hit boost limit in closed loop so quickly? However, when I originally had my PID set to 22,20,70 and normal polarity I was fine, if sub-par. I am using a new style DIYautotune boost solenoid. Any thoughts? I'd really like to start turning the boost up slowly and maybe doing some gear based boost stuff but until I get the closed loop stuff working perfectly I don't think it's the right time. Thanks! |
Change the polarity back to normal.
Be careful using settings from ebc tuning threads esp for ms2. Older msextra firmwares were written such that less duty = more boost. The latest versions have been changed so that more duty = more boost. If the polarity and/or open and closed duties are backwards it will overboost regardless of the pid settings. |
Will do, but why don't they say that on the ms3 documentation site? It still says 0% duty means closed wastegate and more boost.
Boost Control Output Polarity - This is used to set the polarity of the output. Set properly, lower reported duty should correspond to a more closed wastegate and yield more boost. Available options include: Normal - 100% output pin duty means the wastegate is fully open. Inverted - 0% output pin duty means the wastegate is fully open. |
The manual has not been updated to reflect the latest firmwares.
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Well that's helpful... Thanks. I'll give it a try in a few minutes.
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The manual reflects release firmwares, it's only the Alpha's/Beta's currently which have the boost control flipped (to the correct way IMO).
The latest Alpha/Beta firmwares also have tooltips within TunerStudio so you shouldn't need to use the manual anyway. |
did that fix it?
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Yes, but I am not happy with how it is holding boost. I spent about an hour on it yesterday and I am not any happier with MY numbers than the numbers I started out with.
I am not hitting and staying at my targets. My target is 162kpa. Attached are logs at different PID settings. The numbers are in the file name. P19,I20,D71 is what I started with yesterday and what I returned to today. P18,I36,D55 is what I ended with yesterday and I didn't see/feel enough of an improvement and I was unsure if I actually made an improvement. |
what boost does your wastegate only give you?
can you post screen captures of these boost pulls? |
I am away from my tuning laptop for a bit and I will post screenshots when I get back.
My wastegate brings me to about 155-160kpa. |
you should just add preload to your wastegate actuator if you're only targeting like 1 psi over...
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The idea is to start by getting 10psi as soon as possible and ride it to redline. From there, add a pound or so at a time while working on my tune. My eventual goal is about 220lb/ft torque and whatever HP comes with it. You think I would be better served upping my boost target to 175kpa or so while tuning?
By "eventual" I mean the max I am comfortable with until I build an engine. |
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Upped the 100% throttle line target from 162kpa to 170kpa. Raised the overboost to 180kpa.
This is the result: https://www.miataturbo.net/attachmen...1&d=1376958512 Is the "sawtooth" motion normal cycling of the valve? Would I need to raise I and lower P in order to reach my targets? |
i dont think you have enough p. i feel like most people end up around 25-30 or so for p.
you should be tuning by: starting with like 100p only, the rest at zero. reduce p until you breach your tuning during spool up. start doing pulls to redline, increase i to hold target to redline. increase p as you increase i to maintain the spool-up target. increase d to reduce the sin-wave pattern. increase p and i to keep hitting spool-up target and maintain target to redline. increase d to reduce the sin-wave pattern. increase p and i to keep hitting spool-up target and maintain target to redline. eventually get close enough where when you spool you should end up with a 1psi spike over target and hold it to redline with very minimal oscillation. |
Actually that's exactly what I did.
I think that by having my target so close to wastegate I might have been making it difficult to really see what is going on. I am going to start over and set boost limit to 185kpa with a 170 target. Part of the headache is doing this all myself with a sub-par location to do test runs. What gear are you tuning your P in by the way? How about the other two? |
Should I be switching my closed and open duty percentages as well since I a running "Normal"?
Tried working on it during an hour long drive home on country roads. Unfortunately, I hit the + button instead of the = button. I wanted to set my target boost to 62kpa, instead I set it to a target of 330ish kpa with my over boost set to 173. No wonder it wasn't acting predictably. Back to the drawing boards tomorrow. |
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Originally Posted by richyvrlimited
(Post 1044902)
The manual reflects release firmwares, it's only the Alpha's/Beta's currently which have the boost control flipped (to the correct way IMO).
The latest Alpha/Beta firmwares also have tooltips within TunerStudio so you shouldn't need to use the manual anyway. My tunerstudio file says I am running MS3. Here are my pages as they stand this morning: https://www.miataturbo.net/attachmen...1&d=1377263362 https://www.miataturbo.net/attachmen...1&d=1377263362 What gear are you starting your "P" Pull. What RPM? I feel like I am starting with something wrong in my setup which is really making it worse than it needs to be. Also, I don't have tooltips as far as I can tell. |
Originally Posted by Chiburbian
(Post 1046539)
I just checked and I am pretty sure I am using a release version 1.2.3
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closed duty cant be greater than open duty.
you need to make closed = 0% and open = 100% and then use inverted polarity. |
I was right about stuff being fubar. I checked my project properties and it indicated I was running MSZ3 .262 or something like that. I did a "check for ECU" or whatever that button was and it came back with a firmware of 1.2.1.
So I have been running a mismatch of sorts between what tunerstudio thought I was running and what I actually was. This might have something to do with many of my random minor problems. Brain: If I was using alpha code where I would be running normal as opposed to inverted, would I still be keeping closed = 0% and open = 100%? If I were to start over with Alpha code, my settings should be to start: Output Polarity: Normal Closed Duty: 0 Open Duty: 100 Start P at 100 etc... Correct? Am I better off just going to 1.2.3 and running inverted for now to minimize having to make other adjustments? |
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