ITT: MS3X VVT settings and tuning - 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 07-28-2013, 08:08 PM   #41
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 406
Default

That makes more sense. I tried varying VVT over different boost pressures and saw the same thing I saw at max/WOT boost levels. Basically it is was primarily dependednt on RPM.
y8s is offline   Reply With Quote
Old 07-29-2013, 12:54 PM   #42
Elite Member
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Quote:
Originally Posted by 18psi View Post
ahhhh, that makes way more sense. so basically whatever the top row shows is what it will hold, or target, for everything above (and off) the table.

gotcha. thanks
No reason to take that insight too lightly. Some functions (used to?) linearly extrapolate from the last two points - so if you wanted it to keep heading down, you had to have the slope of the final two entries. If you wanted it to stay flat, you had to pin the last two points to the same value.

I forget what that happened on, but it was irritating for sure - if nothing else, to have to move two points each time for something like "warmup enrichment" was a PITA.
AbeFM is offline   Reply With Quote
Old 07-29-2013, 02:50 PM   #43
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 5,309
Total Cats: 1,328
Default

Quote:
Originally Posted by AbeFM View Post
No reason to take that insight too lightly. Some functions (used to?) linearly extrapolate from the last two points - so if you wanted it to keep heading down, you had to have the slope of the final two entries. If you wanted it to stay flat, you had to pin the last two points to the same value.

I forget what that happened on, but it was irritating for sure - if nothing else, to have to move two points each time for something like "warmup enrichment" was a PITA.
Exactly. Having to "steer" VVT tables by fiddling with set points is a PITA.

I always make the last two warmup enrichment values the same for that reason too. Might be nice to have a 3D view for VVT table.
emilio700 is offline   Reply With Quote
Old 07-30-2013, 12:04 PM   #44
Elite Member
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Huh. I was never a huge fan of 3D views. I guess there's nothing wrong with it, I just rarely get more out of it. The color coding helps, but, not if the changes are small in an adjustment with a large range. It does help you pick out a small dip.

I am curious if they'll put in a larger table - they said they would if there was room, but who knows what that means. :-)

We should do another thread for throttle dependant boost settings. There's a couple tricks I did in my MBC setup I'd like to incorporate, and I can't decide if I like it. Keeping temps down is always a plus though.
AbeFM is offline   Reply With Quote
Old 07-30-2013, 03:09 PM   #45
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 5,309
Total Cats: 1,328
Default

3D not a deal breaker. It just makes it easier to see rough spots. It's about arriving at the correct tune faster. That's important for what we do here.
emilio700 is offline   Reply With Quote
Old 10-07-2013, 11:40 AM   #46
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Bumping this thread because I'm still fighting a small bucking/jerking issue on dead cold startup and driving.

In another thread and talking to various folks I learned that before the oil warms up, vvt really doesn't like advance before 3k rpm.

I decreased it to nearly nothing below 3k, with something like 12 degrees at 80kpa at like 2500rpm and full advance arriving at 3k rpm. (I'll post current table when I get home)

That helped a whole lot. But the car will still do it when I drive it cold, though a whole lot less now. It only does it between 2k-3k and only when not completely HOT)

So my question is:
What do those of you that posted a ton of advance below 3k in the cruise regions have to report about cold driving? I'm talking about starting the car in the morning, and just driving off (obviously really light throttle to baby it before it warms up).

Feedback would be greatly appreciated. I wanna make sure its not vvt related before I try other things (messed with accel settings and much other stuff....car runs great otherwise and when fully warmed up)

*edit: here is the other thread for reference:
https://www.miataturbo.net/engine-pe...erature-72889/
18psi is offline   Reply With Quote
Old 10-07-2013, 12:50 PM   #47
Senior Member
 
Join Date: Mar 2006
Location: Schwarzenberg, Germany
Posts: 1,497
Total Cats: 81
Default

I think you should do a datalog of this and post it here.
This could be cold accel, mat corrections and much more...
Zaphod is offline   Reply With Quote
Old 10-07-2013, 01:11 PM   #48
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Ok will do. I don't know why I haven't already done this lol
18psi is offline   Reply With Quote
Old 10-21-2013, 05:41 PM   #49
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

bump

here you go. marked right before it starts. you can see the rpm and everything else get all jumpy when it starts. VVT angle and duty goes berserk and looks like a jigsaw
Attached Files
File Type: msl latest slight cold bucking.msl (1.67 MB, 96 views)
18psi is offline   Reply With Quote
Old 10-21-2013, 06:08 PM   #50
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

I think I need to stop being a lazy bum and just re-tune my PID from scratch rather than copy/pasta of Y8s settings.

I just halfed the values and noticed much more smoothness. Car is nearly warm though. We shall see tomorrow morning when its dead cold for the real results.

PID settings for above log were
50
17
100

current intake table:


ohhhhhh how I wish MS3x had a clt reference for vvt activation
....it would solve all problems lol
Attached Thumbnails
ITT: MS3X VVT settings and tuning-veeveeteez.png  
18psi is offline   Reply With Quote
Old 10-21-2013, 08:38 PM   #51
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 5,309
Total Cats: 1,328
Default

FWIW, we never see two BP6D engines use the exact same PID and base duty settings. Don't know why. I always start with known working settings copied from another car then run a few tests, including target response, accuracy and overshoot on both hot and cold oil.

Last edited by emilio700; 10-21-2013 at 09:41 PM.
emilio700 is offline   Reply With Quote
Old 10-21-2013, 09:10 PM   #52
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Thanks Emilio. My observations are confirming that as well. Time to tune PID from scratch.


*EDIT: I'm stumped - Just went out and zero'd out all the values in pid. started slowly adding P and it shoots to 40* no matter what. Started adding I and it shoots to 40* no matter what.

Then just for funzies I wet P and I to super high numbers, like 100, and now it undershoots.

Are my settings inverted somehow? Or am I grossly mis-understanding how PID for vvt works?

Last edited by 18psi; 10-21-2013 at 09:52 PM.
18psi is offline   Reply With Quote
Old 10-22-2013, 01:13 AM   #53
Senior Member
iTrader: (8)
 
Join Date: Jun 2010
Location: Navarre, FL
Posts: 1,127
Total Cats: 39
Default

Are you VVT guys using the injection timing table (vs using a fixed value) to 'match' your intake cam advance values?
aaronc7 is offline   Reply With Quote
Old 10-22-2013, 05:30 AM   #54
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Quote:
Originally Posted by aaronc7 View Post
Are you VVT guys using the injection timing table (vs using a fixed value) to 'match' your intake cam advance values?
Yep, using table.
Quote:
Originally Posted by 18psi View Post
Thanks Emilio. My observations are confirming that as well. Time to tune PID from scratch.


*EDIT: I'm stumped - Just went out and zero'd out all the values in pid. started slowly adding P and it shoots to 40* no matter what. Started adding I and it shoots to 40* no matter what.

Then just for funzies I wet P and I to super high numbers, like 100, and now it undershoots.

Are my settings inverted somehow? Or am I grossly mis-understanding how PID for vvt works?
To clarify,

when all 3 are zero's, vvt angle is at lowest setting and doesn't move
as soon as the values are over 0, it overshoots like crazy
if I raise the values to extremely high (over 100) it actually undershoots

Anyone got any ideas?

*edit:
If I understand this correctly:
Quote:
VVTuner's advance control implements a closed loop feedback algorithm with PID loop to insure that the amount of advance commanded results in the actual advance. VVTuner constantly monitors the real time target advance value and compares it against the actual value observed by reading the crank and cam position sensors. Any difference between target advance and actual observed values is considered an error. The PID loop will attempt to correct the error. The PID parameters allow real time adjustment of how the error is corrected. PID is comprised of 3 terms:

P. This term tells the VVTuner how aggressively it needs to correct. A higher value here will result in possible quicker correction, but too high of a value can result in overshoot of target and possible oscillations. Too low of a value may result as never being able to reach target.
I. This term tells the VVT tuner how much "acceleration" is needed to bring the observed advance to target advance if the error is large. A larger I value will result in quicker corrections, but too much I value may result in unsteady operation.
D. If I is acceleration, then D is the brakes. The D term will slow corrections down as the observed advance approaches the target. The D term can be implemented to reduce overshoot of target, however too much D term could result in undershoot or the ability to never reach the target.

The idea is to eliminate any advance error as quickly as possible by quickly bringing observed advance to target advance, but slowing down the correction as the error approaches zero such that the target is achieved quickly and without and undershoot, overshoot, or oscillations around the target. The values preprogrammed to VVTuner were found to work well with a standard 2001-2005 Miata VVT motor after extensive research. However, as no two engines are alike, you may need to alter the PID values. Please note that when any of the three parameters are adjusted, the loop is re-initialized and the PID I-value accumulation is reset to its starting point.
Then I need to start at all zero's, then start adding P til I hit target, then I to hit target faster, then D to stabilize hitting target correctly and not overshoot or undershoot.

What am I missing? Why is mine all wonky?
18psi is offline   Reply With Quote
Old 10-22-2013, 08:17 AM   #55
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

IIRC you need to start high and work low. so start with P100 I0 D0.

Lower P until you hit you JUST overshoot the target.

Add I to hold the target to redline.

Add P back to keep hitting target.

Add I to keep holding to redline. Rise. Repeat.

Add D to chill out the oscilliation.
Braineack is offline   Reply With Quote
Old 10-22-2013, 11:43 AM   #56
Senior Member
iTrader: (2)
 
Join Date: Oct 2011
Location: Hickory, NC
Posts: 683
Total Cats: 3
Default

Wow. My Brain is fried....thanks Brain!
Vlad, get this **** figured out so I can copy your table and stop my cold bucking issue....oh wait, didn't I read Emilio saying that won't work? Awwwwhhhh. It will be a good starting point I guess.
Scott, Thanks for the step by step. I am sure this will be a great help when I am ready.

Sticky?
Amellrotts is offline   Reply With Quote
Old 10-22-2013, 02:21 PM   #57
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,174
Total Cats: 2,575
Default

Quote:
Originally Posted by Braineack View Post
IIRC you need to start high and work low. so start with P100 I0 D0.

Lower P until you hit you JUST overshoot the target.

Add I to hold the target to redline.

Add P back to keep hitting target.

Add I to keep holding to redline. Rise. Repeat.

Add D to chill out the oscilliation.
WAT

wow.

So I had it completely backwards, and I guess I misunderstood the whole stupid thing.

Thanks Scott. I will be trying this today.
18psi is offline   Reply With Quote
Old 10-22-2013, 02:53 PM   #58
Senior Member
iTrader: (8)
 
Join Date: Jun 2010
Location: Navarre, FL
Posts: 1,127
Total Cats: 39
Default

There are multiple PID algorithms and MS has changed them around with minimal documentation.. Traditionally what I'm used to is increasing P until you hit or slightly overshoot target. But yeah, idle and boost pid is now like how brain describes as well. Not sure about EGO-- off topic but- anyone know?
aaronc7 is offline   Reply With Quote
Old 10-22-2013, 03:48 PM   #59
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,833
Total Cats: 1,786
Default

idle isn't like that at all.

boost has been this way for the last almost 3 years now.

if you're tuning idle like that, then your idle probably sucks. EGO should be tuned like idle. where you tune from 0 0 0, then increase I first to hold hit the target and P to increase the ramp speed to the target.
Braineack is offline   Reply With Quote
Old 10-22-2013, 04:38 PM   #60
Senior Member
iTrader: (8)
 
Join Date: Jun 2010
Location: Navarre, FL
Posts: 1,127
Total Cats: 39
Default

Thanks for the clarification. I haven't used CL idle in forever I guess it shows.
aaronc7 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
"Chimney Ethanol" E100 MiataGarage Engine Performance 5 09-30-2015 12:04 AM
In need of base map for stock 1997 brandonbkd MEGAsquirt 0 09-29-2015 12:52 AM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 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 08:31 AM.