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Old 12-07-2008, 01:41 AM   #1
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Default Closed Loop Boost Control

Why doesn't it work? I've never heard of anyone getting it hooked up; we all just disable it and go off duty targets. With the temps dropping here in SLO, though, I am getting an absurd disparity between daytime boost and nighttime boost, like 5-6psi. Before I remove the EBC and replace it with a Hallman MBC, does anyone have any tips for closed loop control?
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Old 12-07-2008, 02:15 AM   #2
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While back I did some research on this. Mainly reading on msefi.com forums. From what I gather, the code is written incorrectly. So no matter what values of P, I, and D you use, you'll never get it right because the math written in the code is "wrong". But apparently this is a "secret". IE-the people that wrote it don't think it's wrong, or won't admit it anyways. Of all the reading, I found one post where someone got it to work. They said one of the terms was "backwards" from what it should be. But others tried his settings with no luck.

MBC for me. If someone makes closed loop super easy to setup and it work, I'll think about EBC. Till then....
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Old 12-07-2008, 04:06 AM   #3
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there have been so many threads, I even started one on the ms bord with no help. wtf.
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Old 12-07-2008, 06:37 AM   #4
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The math for the PID at the MSII currently gets a makeover. So maybe this get's changed for MS1 too.

Greets
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Old 12-07-2008, 11:45 AM   #5
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BEn tried using it for a while, his boost oscillated pretty bad IIRC.
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Old 12-07-2008, 12:09 PM   #6
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Quote:
Originally Posted by Savington View Post
Why doesn't it work? I've never heard of anyone getting it hooked up; we all just disable it and go off duty targets. With the temps dropping here in SLO, though, I am getting an absurd disparity between daytime boost and nighttime boost, like 5-6psi. Before I remove the EBC and replace it with a Hallman MBC, does anyone have any tips for closed loop control?
Savington; I can do it with my ECU but I asked my local tuner and he was dead set against it. He said that if I did it and the O2 sensor took a crap I'd be left stranded right there as his reason not to.

Would you care to give me some reasons for doing so?

Thanks
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Old 12-07-2008, 01:00 PM   #7
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what would the O2 sensor have to do with a MAP reading?
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Old 12-07-2008, 01:06 PM   #8
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Has anyone tried just the P value, or just the I? Negative values may be required.

BTW from dicking with the PI of the AEM, they omitted an important step, that the I ONLY kick in when boost is within a 2 psi or so of target. They also omitted the D which is really important to prevent overshoot and have fast response.
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Old 12-07-2008, 01:56 PM   #9
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Quote:
Originally Posted by Rafa View Post
Savington; I can do it with my ECU but I asked my local tuner and he was dead set against it. He said that if I did it and the O2 sensor took a crap I'd be left stranded right there as his reason not to.

Would you care to give me some reasons for doing so?

Thanks

Not closed loop fuel control, closed loop BOOST control. Closed loop fuel is good, most OEMs use it, or you can just tune your car correctly and leave it off so when your wideband takes a **** you can drive home anyway.
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Old 12-07-2008, 02:23 PM   #10
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Quote:
Originally Posted by Savington View Post
Not closed loop fuel control, closed loop BOOST control. Closed loop fuel is good, most OEMs use it, or you can just tune your car correctly and leave it off so when your wideband takes a **** you can drive home anyway.
Oops!


Quote:
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what would the O2 sensor have to do with a MAP reading?
I don't use the car's MAP sensor. I'm using a MAF Toyota sensor. And you're right; my bad.
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Old 12-07-2008, 03:18 PM   #11
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Spent a year trying to get mine to work right. Just went MBC and the car is finally stable in varied temps.
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Old 12-07-2008, 03:38 PM   #12
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Quote:
Originally Posted by Braineack View Post
BEn tried using it for a while, his boost oscillated pretty bad IIRC.
I did try it for a little while. I spent the time to log duty cycle and MAP at various TPS and RPM and set my target tables up appropriately. It worked OK, however when corrections came in, they were a little too severe. A little overshoot, followed by a little undershoot, and so on. It was tolerable, and probably could have been very useful if set up to cure overshoot before hitting boost cut, if nothing else.

However when I started playing with the other features--the boost cut with intake temp and boost cut with knock--it would severely overreact and pull way too much duty cyle, then try to add way too much duty cyle, then pull it again, and so on. It was horrible, so I disabled it and went back to target table only.

MS does .msq switching. If you're not using the feature currently, you could always load in the same msq with 2 different EBC duty cyle tables and switch for warm/cold. It's also very useful if you like big smokey burn outs. Tip of the day: Run on the low boost msq, apply heavy throttle to where you'd be fully spooled on the high boost msq, then flip the switch. The extra boost will come in immediately and light the rear up.
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Old 12-07-2008, 03:41 PM   #13
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Keith on MSExtra is looking at sorting the code out.

He's working on proper PID for closed loop idle and once that's done he's going to look at the closed loop boost control.

Moot point for me seeing as I use a superior method of attaining Forced induction, but for the rest of you it should be sorted pretty soon-ish.

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Old 12-14-2008, 07:05 PM   #14
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I would really like this closed loop control to work. I only get to run 10psi all winter because the cold weather makes it fluctuate too much during the day to run a reliable 13.
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