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-   -   MS3x Closed Loop EBC (https://www.miataturbo.net/megasquirt-18/ms3x-closed-loop-ebc-110975/)

Micechuck Nov 26, 2025 09:35 PM

MS3x Closed Loop EBC
 
4 Attachment(s)
Hello all,

Definitely tried searching, but was unable to find specific information regarding the following as it's a fairly specific question;

When tuning closed loop boost control with MS3 1.6.1, my boost comes right up to target but then drops below by 2-3 PSI (2040s in the log, for example). Initially i thought i could tune this out by adjusting PID terms or my duty table, but even at the extremes of all 3 terms, i still have similar results. My bias duty table is fairly close in setup mode, although it's much better in gears 4-5 than 2-3. I tend to overshoot in the lower gears and it overshoots every time between aggressive/fast gear changes.

My specific, any perhaps stupid question; I notice in my logs that the injector PW drops significantly at the same time as my boost does - is this because my boost duty dropped, or is it potentially causing it due to too low VE in my fuel table? My apologies if this is a completely uninformed noob question - i try to do my best at reading existing lit but search ain't always the best and i'm definitely still learning.

My apologies for zip file - log was like 35mb. If it's a problem, i can try to find another way to trim/just make another log worse comes to worse

Appreciate any feedback, either specifically on the question or generally on the tune/log.

Thanks,
-Mice

Micechuck Nov 27, 2025 01:55 PM

Well i can't figure out how to delete my post but i feel like an idiot. I just happened to be poking around in my engine bay the other day and noticed my EBC was hooked up backward. I had the right ports in use, but the compressor / wastegate lines were swapped.

Swapped them back and started over this morning - duty table is much closer to 40 - 60% instead of 88 - 94% as previously. Closed loop does a much better job when your ebc is hooked up right...


https://cimg3.ibsrv.net/gimg/www.mia...c4b08da673.png


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