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I have a 97 Miata. stock engine with full MKturbo kit running MS3PNPRO and diyautotunes EBC solenoid. I have read a ton of info on this site about close loop settings and what others are using, but something is not right about mine. It hits overboost (set at 195kpa) pretty much all the time. I even tried setting my boost target table to 150 kpa max and set duty bias table to 0 and if I do a WOT pull in 3rd or 4th gear from 2k rpm ill hit 195 kpa and overboost before I even get to 4500 rpm. I have tried moving the min and max duty cycles from 1 and 100 to 15 and 86 like I have seen suggested. I have also tried moving the sensitivity slider around, but it doesn't seem to make a difference. I have also tried to change the delta limit around, and it also doesn't seem to make a difference.
Do I have too much preload on the wastegate actuator arm? that shouldn't make a difference though right? I had the boost at 9psi using preload before hooking up the EBC. I have attached the previous tune I was using (this was still set to 1 and 100, but I had changed it after but it made no difference).
Post a log.
Go to advanced and set I to about 7, maybe 6.
Consider going to 1.5.2 beta 2, or wherever they set it up to allow SD card logging of the P, I, D, time for some of the PID loops, EBC included. Then you can see exactly what is happening (if you have an SD card installed). If you don't like the beta, you can go back, but for troubleshooting this issue, it could be a good idea.
Aside from that, as I mentioned the I. Typically, if you call for any boost, by the time you spool up, 1.5.1 will add so much Integral wind-up that you will go right into overboost. Take the integral way down to keep that from happening. Maybe even to zero to start.
Post a log.
Go to advanced and set I to about 7, maybe 6.
Consider going to 1.5.2 beta 2, or wherever they set it up to allow SD card logging of the P, I, D, time for some of the PID loops, EBC included. Then you can see exactly what is happening (if you have an SD card installed). If you don't like the beta, you can go back, but for troubleshooting this issue, it could be a good idea.
Aside from that, as I mentioned the I. Typically, if you call for any boost, by the time you spool up, 1.5.1 will add so much Integral wind-up that you will go right into overboost. Take the integral way down to keep that from happening. Maybe even to zero to start.
DNM
I tried posting a log but the site said the file was too big even though it wasn't. I'll set the I real low.. right now its on basic tuning which has P I and D all at 100 i believe.
Attached is a log from today. Sorry its so long, go to near the end and I was able to do a 4th gear WOT pull (not to redline due to traffic). I have also attached the current tune. I have the boost target table set to 150kpa and I am still hitting a little over 175kpa. Im just not sure why hits hitting 25kpa over what I have it set too. I had the bias table at 5, and moving it to 0 does nothing.
This is also with changing closed loop boost control to advance and changing I to 7 like you suggested. Could the issue have to do with the EBC solenoid being so far from the turbo? I put the EBC solenoid on the passenger side of the engine bay because its cooler and dityautone says to keep the solenoid at or below 122 degrees. So I have vac line running from the wastegate to the EBC solenoid and then another vac line from the solenoid to the boost source, which on my setup is on the intercooler piping roughly 6 inches from the throttle body.
Hoses seem less than ideal, but is not likely the issue.
What is your waste gate boost level?
175 is better than 195+.
True. I have target to 160 now and it hit 180 max on a 4th gear 2k wot pull. So that's where ill leave it for now. Here are the current tables. Still not sure what to.do with bias table but ill just leave it as is.
Your closed duty is set to 15% and this seems too high (which is strange - could you try to switch the output polarity to inverted?) - the duty cycle jumps to 15% and stays there because you are already over the target and because of the closed duty of 15% its not able to lower the duty cycle.
Also there is a thread on how to set your EBC- try using open loop first to get a feel for the correct duty cycles at different rpm/load combinations and use these to set your inital value table, that makes the CL EBC way more effective.
Your closed duty is set to 15% and this seems too high (which is strange - could you try to switch the output polarity to inverted?) - the duty cycle jumps to 15% and stays there because you are already over the target and because of the closed duty of 15% its not able to lower the duty cycle.
Also there is a thread on how to set your EBC- try using open loop first to get a feel for the correct duty cycles at different rpm/load combinations and use these to set your inital value table, that makes the CL EBC way more effective.
yeah I see what your saying. On open loop I had the min and max to 0 and 100 and had the duty cycles at 20 max. Anything over on that would overboost as well. I had changed to 15 and 86 based on reading other threads that the solenoid isn't active until those levels and if you shorten the duty cycles the closed loop will work better.
in my case, I've tried several different settings based on what ive read on here and none of them make much of a difference. I still hit 20-25kpa above what my target is. I think I'm going to turn boost control off and do a pull and then turn back on and log the differences.
Open and closed min/max are a function of frequency, solenoid voltage, and coil driver circuit. If you aren't using the same things in all of these categories, then you can't use what other people say "works".
In general, the min for reliable control on all of the solenoids I have characterized is ~30 and the max is around 80 (for 3-port). This is not hard and fast. This doesn't mean that the solenoid doesn't "click" outside of this range, or that you don't see changes in the regulated pressure while testing open loop outside of this range. It means that the response in regulated pressure to changes in DC becomes predictable. This is a requirement for properly tuned PID.
The minimum regulated boost pressure that you should target for a given WG spring using EBC can be approximated by dividing the spring rate by 0.7. This will provide control margin both above and below target and help prevent windup into an area where the solenoid doesn't respond predictably.
The maximum in general is 2x spring for 2-port, 2.5x spring for 3-port, and 4-port is dumb don't use it unless you know what you are doing and why. 3-port is by far my favorite configuration, I will not go into why here.
EBC tuning STARTS with a detailed characterization of the open loop response. If you hit overboost while open loop at low commanded DC (like less than 50) then you might want to look at a lighter spring in order to get better control resolution. You need to be able to answer the question "what will the manifold pressure be at 'x' DC and 'y' RPM?" Where x is any number between 0 and 100 and y is any RPM where you want good control. Without this understanding you are just trying things to see if they work, IOW shot in the dark.
Once you develop a fundamental understanding on how this thing works, EBC becomes super easy.
Open and closed min/max are a function of frequency, solenoid voltage, and coil driver circuit. If you aren't using the same things in all of these categories, then you can't use what other people say "works".
In general, the min for reliable control on all of the solenoids I have characterized is ~30 and the max is around 80 (for 3-port). This is not hard and fast. This doesn't mean that the solenoid doesn't "click" outside of this range, or that you don't see changes in the regulated pressure while testing open loop outside of this range. It means that the response in regulated pressure to changes in DC becomes predictable. This is a requirement for properly tuned PID.
The minimum regulated boost pressure that you should target for a given WG spring using EBC can be approximated by dividing the spring rate by 0.7. This will provide control margin both above and below target and help prevent windup into an area where the solenoid doesn't respond predictably.
The maximum in general is 2x spring for 2-port, 2.5x spring for 3-port, and 4-port is dumb don't use it unless you know what you are doing and why. 3-port is by far my favorite configuration, I will not go into why here.
EBC tuning STARTS with a detailed characterization of the open loop response. If you hit overboost while open loop at low commanded DC (like less than 50) then you might want to look at a lighter spring in order to get better control resolution. You need to be able to answer the question "what will the manifold pressure be at 'x' DC and 'y' RPM?" Where x is any number between 0 and 100 and y is any RPM where you want good control. Without this understanding you are just trying things to see if they work, IOW shot in the dark.
Once you develop a fundamental understanding on how this thing works, EBC becomes super easy.
Thank you! Im not sure why, but the way you explained it made it click better with me. I think one of my main issues, like you said is that I was hitting overboost at a very low command. I had too much preload on my wastegate actuator and was hitting around 10psi with the EBC turned off. My goal is only 12-13 psi so I believe I was just too close to the target on wastegate alone. I reduced the preload until I was at about 7psi with no EBC. Then I started the setup mode of closed loop to get my DC values set up
I did some testing in open loop and found that anything under 30 doesn't make any difference, so I set my minimum to 25 and left the max at 86 for now (still need some minor adjusting). I found that I was hitting my target 180-185kpa around 55. I then put the closed loop in basic mode with the slider set to 240. It is working so much better now.
I still have some minor tuning to do. I have target set to 185 kpa, but I hit a max of 192kpa and then it will taper down to 180-185. I may have the max DC value to high at 86 still. Looking at my log DC goes to 86 and then starts coming down as boost is still building. DC keeps coming down and down and boost will keep going and kind of spike at that 192 and then drop down.
Attached is my latest tune. Had to attach log as a compressed file bc the forum said it was too large a file. Let me know what you think.
Last edited by user 8202; 05-13-2020 at 09:15 PM.
Reason: attachment add
An overshoot of 7kpa is totally reasonable. I wouldn't go after that too hard. If you really want to go after it, the parameters you want to play with are the lower limit delta (most likely reduce) and the solenoid frequency (most likely increase). This assumes a very well tuned bias duty table. Adjusting these parameters may have side effects that are less desirable than a 7kpa overshoot.
Edit: FYI, I do not really open tunes posted to forums. If you want me to know how these things are setup in your tune, post a screen shot.
05-10-2020, 01:00 PM
Closed loop EBC settings
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