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Old 08-18-2013, 06:08 PM   #1
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Default Boost PID=200,0,0 - still hits boost limit

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!
Attached Files
File Type: msq 8_16tocompare.msq (172.2 KB, 96 views)
File Type: msl 08-18_closed_loop.msl (30.1 KB, 72 views)
File Type: msl 08-18_wastegate.msl (68.8 KB, 83 views)
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Old 08-18-2013, 07:06 PM   #2
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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.
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Old 08-18-2013, 07:15 PM   #3
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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
Quote:
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.
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Old 08-18-2013, 07:17 PM   #4
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The manual has not been updated to reflect the latest firmwares.
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Old 08-18-2013, 07:18 PM   #5
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Well that's helpful... Thanks. I'll give it a try in a few minutes.
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Old 08-19-2013, 04:39 AM   #6
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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.
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Old 08-19-2013, 08:07 AM   #7
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did that fix it?
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Old 08-19-2013, 11:18 AM   #8
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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.
Attached Files
File Type: msl 08-18_P18_I36_D45.msl (107.0 KB, 89 views)
File Type: msl 8-19_P19_I20_D71.msl (54.1 KB, 64 views)
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Old 08-19-2013, 11:20 AM   #9
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what boost does your wastegate only give you?

can you post screen captures of these boost pulls?
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Old 08-19-2013, 11:31 AM   #10
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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.
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Old 08-19-2013, 11:48 AM   #11
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you should just add preload to your wastegate actuator if you're only targeting like 1 psi over...
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Old 08-19-2013, 11:52 AM   #12
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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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Old 08-19-2013, 09:30 PM   #13
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Upped the 100% throttle line target from 162kpa to 170kpa. Raised the overboost to 180kpa.

This is the result:


Is the "sawtooth" motion normal cycling of the valve? Would I need to raise I and lower P in order to reach my targets?
Attached Thumbnails
Boost PID=200,0,0 - still hits boost limit-boost8_19.jpg  
Attached Files
File Type: msl 2013-08-19_18.15.18.msl (58.2 KB, 89 views)
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Old 08-20-2013, 08:22 AM   #14
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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.
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Old 08-20-2013, 09:37 AM   #15
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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?
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Old 08-23-2013, 01:47 AM   #16
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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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Old 08-23-2013, 10:11 AM   #17
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Quote:
Originally Posted by richyvrlimited View Post
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.
I just checked and I am pretty sure I am using a release version 1.2.3

My tunerstudio file says I am running MS3.

Here are my pages as they stand this morning:




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.
Attached Thumbnails
Boost PID=200,0,0 - still hits boost limit-screen-shot-2013-08-23-8.07.54-am.jpg   Boost PID=200,0,0 - still hits boost limit-screen-shot-2013-08-23-8.08.12-am.jpg  
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Old 08-23-2013, 10:40 AM   #18
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Quote:
Originally Posted by Chiburbian View Post
I just checked and I am pretty sure I am using a release version 1.2.3
In which case it's as per the manual, and more duty = less boost.
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Old 08-23-2013, 11:21 AM   #19
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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.
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Old 08-23-2013, 11:59 AM   #20
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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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