Miata Turbo Forum - Boost cars, acquire cats.

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-   MEGAsquirt (https://www.miataturbo.net/megasquirt-18/)
-   -   Preferred Method of EBC Tuning MS3 1.4.1 (https://www.miataturbo.net/megasquirt-18/preferred-method-ebc-tuning-ms3-1-4-1-a-92161/)

Bronson M 04-27-2017 05:51 PM

Say what?!? 200 is LESS responsive than 0? Can anyone confirm this?

aidandj 04-27-2017 05:51 PM

According to Ken its now a standard PID control. So more P is more coefficient.

aidandj 04-27-2017 05:54 PM

Basic mode is
P: 100
I: 100
D: 100

leboeuf 04-27-2017 06:09 PM

Lol, I know its freeware so I can't complain too much... but I like the "don't RTFM, sift through my rambling forum posts"
Does Ken ever explicitly state if they're still arbitrarily inverting things or not?

From the manual:
2. Set Proportional gain to 100% 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 (100% 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 dramatically, increase
the Proportional gain. Otherwise, reduce the Proportional gain and try again. Do this until boost
reaches the target with a small amount of overshoot.

aidandj 04-27-2017 06:15 PM

I believe that is incorrect in the latest firmware. But I could not tell you. It should be an easy test though

Bronson M 04-27-2017 06:23 PM

I had a multi paragraph rant typed up on how tuning is made to be artificially hard......but I'll just thank those that are willing to share and start working on a better sticky post with links and explanations on the gotchas that aren't obvious to the beginner.

aidandj 04-27-2017 06:30 PM

What you need to realize is msextra and all the firmware is done by 2 guys...In their spare time...After their day jobs. They have families, lives, etc. And I find it amazing that we have the documentation we do. I sure as hell couldn't produce that. Megasquirt was not meant to be perfect and super easy​ to use. It's a diy solution that has been commercialized. There are other platforms that promise that.

Bronson M 04-27-2017 06:33 PM

Absolutely, I get that, but the folks that are making darn good money off of their efforts should be helping the community........all I see is them making money off of others hard work.

DNMakinson 04-27-2017 07:40 PM

Here are my present settings with results:

Slightly more over-boost on stab at 50 MAT than 70 MAT, but pretty good. I have not played a lot with D as usually PID need very little D, unless this is somewhat scaled. I have tried up to D=2 with no noticeable change. D is to get large Control Output very quickly when Variable is far from SP.

https://cimg4.ibsrv.net/gimg/www.mia...fbb9109095.png

Note Control Lower Limit is set so high as to be non-existent, but if you look at log, the Control Output goes to max due to high P and I.

https://cimg2.ibsrv.net/gimg/www.mia...5ee57053e9.png

210 would use full SP duty, but I have not called for that much kPa yet.

https://cimg3.ibsrv.net/gimg/www.mia...3d5a63882c.png

Here are my actual targets. I drop at 7K to maybe help save my stock oil pump. Conjecture on my part as to why Mazda put 6500 rev limit on MSM.

https://cimg1.ibsrv.net/gimg/www.mia...d52361388c.png

See Control Output in green on 2nd chart maintaining the PV at SP. Look a few posts up for another log of Boost following throttle.

Note: There is not "standard" PID. Some controllers use P = Proportional Band, and bigger is smaller, some use Gain, and bigger is more. This is all Gains. Some use I is actually P*I. I think this is separate I in the equation.

Set bias table at typical values, like an Open Loop. In leboeur's case, he would want to set his bias table in the middle of his low land needs and high land needs. Then the PID corrects for the error between those bias outputs and the true needs of Boost-Target on a real time basis.

fwman1 04-30-2017 09:50 AM

So DNMakinson, it looks like you are getting acceptable results with larger PID values, but your Delta is fairly high at 90. Do you recall how it behaved at lower Delta and the higher PID values? Did you try that combo?
Cats for sharing, btw.

DNMakinson 04-30-2017 10:27 AM


Originally Posted by fwman1 (Post 1410024)
So DNMakinson, it looks like you are getting acceptable results with larger PID values, but your Delta is fairly high at 90. Do you recall how it behaved at lower Delta and the higher PID values? Did you try that combo?
Cats for sharing, btw.

It behaved similarly. I made it really high as to be ignored to help the overshoot. But, as I mentioned, DC still goes to max at punch, which is the purpose of that setting. So, seems to not matter with the rest of my set-up.

sonofthehill 04-30-2017 08:11 PM

Not having used 1.4.1 yet, here's my :2cents:

There is a small icon to the left of each parameter describing it. I think for each firmware, if you are in doubt, you should refer to that description in your project with your firmware.

Just to be a punk, I am re-tuning my EBC currently with a stiffer spring to hold more boost up top. My PID's are currently p34 i9 d136, MS2PNP 3.3.1 IIRC. I am not quite there yet and it took probably 30 or 40 good logs to get where I am.

DNMakinson 04-30-2017 08:40 PM

Dear Son... What is the title of this thread?

You do have me inquisitive about high "D", though. I may try some and see results.

sonofthehill 04-30-2017 11:25 PM


Originally Posted by sonofthehill (Post 1410122)
There is a small icon to the left of each parameter describing it.

Uh, is dis da title ;) I said to be a punk

fwman1 06-17-2017 09:59 PM

FYI
1.5.1 beta 3 was updated to include SD card logging for the clbc PID values (closed loop idle too). My tuner was able to use this info to finally sort out the non-responsive closed loop boost control.

DNMakinson 06-18-2017 07:16 AM


Originally Posted by fwman1 (Post 1422409)
FYI
1.5.1 beta 3 was updated to include SD card logging for the clbc PID values (closed loop idle too). My tuner was able to use this info to finally sort out the non-responsive closed loop boost control.

Just so I fully understand. Are you saying that it will actually plot the instantaneous values of the contribution to the output from the bias plus each of the three gain equations?

Could you post a log?

fwman1 06-18-2017 10:55 AM

I still have not gotten the car back, but yes that is my understanding.

My tuner had been in contact with Matt from DIY, who helped make the logging of these values possible, so Props and Cats to Matt.

To be honest, my understanding of the PID formula inner workings is sketchy at best. From what he said, once my tuner had the values real time it only took four runs for him to get the CLBC to respond as you'd expect. I had personally seen many threads where folks had a hard time getting the CLBC to engage consistently, and those who had were having to deal with slow spool in some areas to get the overshoot under control in higher gears, or very rapid escalation of boost.

So, I apologize for the lack of detail, but I thought it would be good to let folks know this feature was available/coming. I will post more info once I have the car back.

DNMakinson 06-18-2017 01:50 PM

OK, thanks. My settings are 145, 190, 10 @ 469 slider. I agree that these are not sensible to me, but are giving decent results over time and temp.

Evolforce2 08-06-2017 12:42 PM

I used DNMakinson setting and it completely smoothed out my boost control (exception i have the slider setting down to 350). I am using the DIYautotune boost control valve set at 12lbs 185KPA with boost cut at 205KPA. Initially i was in open loop boost control which worked well, but kept hitting boost cut which i still cannot solve. I was initially hitting boost cut in closed loop with the slider at 470, but as i reduce the slider the tendency of hitting boost cut lessened. The boost cut still activates when i drop a gear on the freeway and stab the throttle WOT. I just not sure how to fix that problem yet. Thank you for this great information guys.

aidandj 08-06-2017 12:45 PM


Originally Posted by DNMakinson (Post 1422425)
Just so I fully understand. Are you saying that it will actually plot the instantaneous values of the contribution to the output from the bias plus each of the three gain equations?

Could you post a log?

Megasquirt Support Forum (MSEXTRA) ? Data logging P, I, and D contributions to closed loop (View topic)


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