MS2 Boost control - Am I missing something? - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 05-18-2015, 03:46 PM   #41
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,892
Total Cats: 1,792
Default

seems really high for the I value, you shouldn't be over like 40-50 on any value--MAYBE D. that's what causing it.

start I at 0 and increase until it can hold the target to redline--its long term tracking.


aidandj gets props for the drop shadowed screenshot.
Braineack is offline   Reply With Quote
Old 05-18-2015, 03:47 PM   #42
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Did you tune basic mode first?
aidandj is offline   Reply With Quote
Old 05-18-2015, 03:49 PM   #43
Sadfab Union President
Thread Starter
iTrader: (3)
 
Join Date: May 2014
Location: Kansas
Posts: 2,690
Total Cats: 113
Default

Wait a miniute, I'm dumb. I meant P, not I. I have I and D set at zero right now, I've been following this, starting at 150 and working down.



To Tune PID:

1. Set Integral and Differential Gains to 0% - To make tuning the Proportional gain easier, set the Integral and Differential gains to 0%.

2. Set Proportional gain to 150% and slowly lower - While tuning Proportional gain, higher numbers mean slower boost climb and lower final boost. For safety, start with a very high gain (150% should be sufficient). Find the RPM that typically spools quickly, and fully and quickly depress the accelerator. Note how much boost is reached. If boost overshoots the target, increase the Proportional gain. Otherwise, reduce the Proportional gain and try again. Do this until boost reaches the target with little or no overshoot.

3. Tune the Integral Gain - The next step after the target is reached consistently is to tune the Integral gain. Starting from the RPM used to tune the P-gain, fully depress the accelerator and watch the boost as the engine climbs through the RPM range. As the engine accelerates through the rev range, the boost will probably creep away from the target. Keep increasing the I gain until the controller adequately maintains the target with minimal oscillation.

4. Tune the Derivative Gain - If overshoot cannot be tuned out with the P gain on a quick acceleration, increase the D gain until the overshoot is minimized. Care must be taken when increasing the D gain as too much D gain can over-dampen the effects of the P and I gains.

No basic mode, does that slider do anything in PID mode? In MS2 that's all you get with basic AFAIK.
deezums is offline   Reply With Quote
Old 05-18-2015, 03:51 PM   #44
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Here is an example of just basic mode:

aidandj is offline   Reply With Quote
Old 05-18-2015, 03:52 PM   #45
Junior Member
 
Join Date: Jan 2014
Location: Port Saint Lucie,FL
Posts: 418
Total Cats: 3
Default

Quote:
Originally Posted by deezums View Post
I think this run was at I125 or I130 or thereabouts, I was starting to subtract a bit form each run to get the overspool I want before I went home for the night. Do you have an initial overshoot, or at least one tuned out?

Need to go back out again, more tuning

Do you remember where you were getting this T3 to spool Scott? I'm pretty impressed for a <$200 5K+mi turbo.
No initial overshoot. I also have the lower limit delta at 27kpa. If it is lower than that, it will want to overshoot. I don't think the EBC can react quick enough to prevent overshooting with a lower delta, especially if you stab the throttle in a higher gear.
Mech5700 is offline   Reply With Quote
Old 05-18-2015, 03:53 PM   #46
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

With the new code it does pretty well

Here is my best pull from this morning with a 20kpa delta

Peaks at 189. Max 192.

aidandj is offline   Reply With Quote
Old 05-18-2015, 03:55 PM   #47
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Also, is it still set as 100%=less boost? That won't work.
aidandj is offline   Reply With Quote
Old 05-18-2015, 04:05 PM   #48
Sadfab Union President
Thread Starter
iTrader: (3)
 
Join Date: May 2014
Location: Kansas
Posts: 2,690
Total Cats: 113
Default

Nah, that's been inverted again. 100%=allofit
deezums is offline   Reply With Quote
Old 05-18-2015, 04:08 PM   #49
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

OK good.

Also the slider is active in advance mode. Remember that.
aidandj is offline   Reply With Quote
Old 05-18-2015, 04:09 PM   #50
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Quote:
Originally Posted by Braineack View Post
aidandj gets props for the drop shadowed screenshot.
OSX. Cmd+shift+4 then space bar.
aidandj is offline   Reply With Quote
Old 05-18-2015, 04:11 PM   #51
Junior Member
 
Join Date: Jan 2014
Location: Port Saint Lucie,FL
Posts: 418
Total Cats: 3
Default

Quote:
Originally Posted by aidandj View Post
OK good.

Also the slider is active in advance mode. Remember that.
If you have PID set so you have a decent boost plot, what would adjusting the slider do? What necessitates slider adjustments?
Mech5700 is offline   Reply With Quote
Old 05-18-2015, 04:16 PM   #52
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

You should use the slider first then use the PID.

Quotes from Ken, the dev:

Quote:
Technically it [the slider] affects how sensitive it is to changes in input. The input and target get converted to a percentage, the more sensitive, the larger that percentage changes given a particular change in boost. Think of it as a gain that affects all three PID gains at the same time by the same amount.
Quote:
Changing between 1 and 0 shouldn't make that much difference... All that says to me is that it's a lot too sensitive... The change I'm planning to do is basically at the end of the PID calcs there's a division that divides off all the extra digits (we control the valve in 1% increments, but the internal calculations start at .01% precision... when the PID gains are multiplied in, that essentially multiplies it to .0001 precision, then that gets divided off at the end). I may have done the math wrong, or even if I did it right it might be a little to sensitive to be practical. So I can add a 0 to the end of the divisor there which should reduce the sensitivity by 10x and make the slider actually useful again.
aidandj is offline   Reply With Quote
Old 05-18-2015, 04:31 PM   #53
Junior Member
 
Join Date: Jan 2014
Location: Port Saint Lucie,FL
Posts: 418
Total Cats: 3
Default

Quote:
Originally Posted by aidandj View Post
You should use the slider first then use the PID.

Quotes from Ken, the dev:
That's how I saw it, but when I had slider even at 0, I would still get wild oscillations. However, this was with delta at 14, and intervals at 20ms... it could have been those factors that made the slider ineffective.
Mech5700 is offline   Reply With Quote
Old 05-18-2015, 04:32 PM   #54
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

I had the same issue, there is now test code that basically desensitizes the slider, it made a huge difference for me.
aidandj is offline   Reply With Quote
Old 05-18-2015, 08:17 PM   #55
Junior Member
 
Join Date: Jan 2014
Location: Port Saint Lucie,FL
Posts: 418
Total Cats: 3
Default

Just for *****, here is a 4th gear pull from 55 mph, then shifting to 5th and goin a little more:



Any idea what I can do to help lessen that dip after I get into 5th?

Here is the settings I currently run:

Mech5700 is offline   Reply With Quote
Old 05-18-2015, 08:21 PM   #56
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Looks like too much I. That looks like integral windup to me. Also tune the slider if you can.
aidandj is offline   Reply With Quote
Old 05-18-2015, 08:48 PM   #57
Junior Member
 
Join Date: Jan 2014
Location: Port Saint Lucie,FL
Posts: 418
Total Cats: 3
Default

I was tuning I this morning, and the boost was getting more stable the higher "I" was.

Haven't really messed with the slider tho.

Was thinking possibly tweaking the initial boost duty in that particular area might help too.
Mech5700 is offline   Reply With Quote
Old 05-18-2015, 08:50 PM   #58
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Also try some D. That will slow the response and maybe help smooth the peak.
aidandj is offline   Reply With Quote
Old 05-18-2015, 08:56 PM   #59
Junior Member
 
Join Date: Jan 2014
Location: Port Saint Lucie,FL
Posts: 418
Total Cats: 3
Default

Side note: Target is 15psi, it peaks at 15.1, dips to about 14.1 and then stabilizes around 14.7~14.8 so the dip isn't that significant...

I'll try adding some D by what, 5 points at a time and see what happens?
Mech5700 is offline   Reply With Quote
Old 05-18-2015, 08:58 PM   #60
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,999
Total Cats: 1,466
Default

Start with 1. Then 2 then add 3 etc. Make small changes. It should hopefully smooth the peak into a curve and not drop the duty so low.
aidandj is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
Missing/knock at idle, can someone point me in the right direction? Mikel MEGAsquirt 4 09-28-2015 05:46 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:20 AM.