MEGAsquirt A place to collectively sort out this megasquirt gizmo

Closed Loop Boost Control

Thread Tools
 
Search this Thread
 
Old 12-07-2008, 12:41 AM
  #1  
Former Vendor
Thread Starter
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
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?
Savington is offline  
Old 12-07-2008, 01:15 AM
  #2  
Elite Member
iTrader: (16)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 9,295
Total Cats: 476
Default

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....
patsmx5 is offline  
Old 12-07-2008, 03:06 AM
  #3  
Elite Member
iTrader: (12)
 
cardriverx's Avatar
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,573
Total Cats: 12
Default

there have been so many threads, I even started one on the ms bord with no help. wtf.
cardriverx is offline  
Old 12-07-2008, 05:37 AM
  #4  
Elite Member
 
Zaphod's Avatar
 
Join Date: Mar 2006
Location: Schwarzenberg, Germany
Posts: 1,553
Total Cats: 101
Default

The math for the PID at the MSII currently gets a makeover. So maybe this get's changed for MS1 too.

Greets
Zaphod is offline  
Old 12-07-2008, 10:45 AM
  #5  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,493
Total Cats: 4,080
Default

BEn tried using it for a while, his boost oscillated pretty bad IIRC.
Braineack is offline  
Old 12-07-2008, 11:09 AM
  #6  
Elite Member
iTrader: (22)
 
Rafa's Avatar
 
Join Date: Dec 2006
Location: Sunny Spanish speaking Non US Caribbean
Posts: 3,224
Total Cats: 3
Default

Originally Posted by Savington
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
Rafa is offline  
Old 12-07-2008, 12:00 PM
  #7  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,493
Total Cats: 4,080
Default

what would the O2 sensor have to do with a MAP reading?
Braineack is offline  
Old 12-07-2008, 12:06 PM
  #8  
Elite Member
 
JasonC SBB's Avatar
 
Join Date: Jul 2005
Posts: 6,420
Total Cats: 84
Default

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.
JasonC SBB is offline  
Old 12-07-2008, 12:56 PM
  #9  
Former Vendor
Thread Starter
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Default

Originally Posted by Rafa
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.
Savington is offline  
Old 12-07-2008, 01:23 PM
  #10  
Elite Member
iTrader: (22)
 
Rafa's Avatar
 
Join Date: Dec 2006
Location: Sunny Spanish speaking Non US Caribbean
Posts: 3,224
Total Cats: 3
Default

Originally Posted by Savington
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!


Originally Posted by Braineack
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.
Rafa is offline  
Old 12-07-2008, 02:18 PM
  #11  
Senior Member
iTrader: (4)
 
posidon42's Avatar
 
Join Date: Aug 2007
Location: Omaha, NE
Posts: 616
Total Cats: 0
Default

Spent a year trying to get mine to work right. Just went MBC and the car is finally stable in varied temps.
posidon42 is offline  
Old 12-07-2008, 02:38 PM
  #12  
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
Default

Originally Posted by Braineack
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.
__________________
Chief of Floor Sweeping, DIYAutoTune.com & AMP EFI
Crew Chief, Car Owner & Least Valuable Driver, HongNorrthRacing

91 Turbo | 10AE Turbo | 01 Track Rat | #323 Mazda Champcar

Originally Posted by concealer404
Buy an MSPNP Pro, you'll feel better.
Ben is offline  
Old 12-07-2008, 02:41 PM
  #13  
Elite Member
iTrader: (1)
 
richyvrlimited's Avatar
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,642
Total Cats: 42
Default

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.

richyvrlimited is offline  
Old 12-14-2008, 06:05 PM
  #14  
Elite Member
iTrader: (3)
 
skidude's Avatar
 
Join Date: Apr 2008
Location: Outside Portland Maine
Posts: 2,023
Total Cats: 19
Default

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.
skidude is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Full_Tilt_Boogie
Build Threads
84
04-12-2021 04:21 PM
Corky Bell
Prefabbed Turbo Kits
18
11-22-2016 09:01 PM
Trent
WTB
2
10-01-2015 12:15 PM
The Gleas
MEGAsquirt
3
10-01-2015 09:30 AM
shooterschmidty
Engine Performance
8
09-30-2015 10:28 PM



Quick Reply: Closed Loop Boost Control



All times are GMT -4. The time now is 02:06 PM.