ECMTuning - wiki

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<h1>ECU-based Boost Control Setup</h1> <div class="level1"> </div> <h2>Disclaimer/notes</h2> <div class="level2"> <p> The <a href="/wiki/doku.php?id=bcsoverview" class="wikilink1" title="bcsoverview">basic operation</a> of ECU-based boost control in ECMLink is fairly straight forward. You dial in a base duty cycle that gets you somewhere in the range of the boost target you want and then enable error correction for fine tuning. But setting up the base duty cycle table and target boost values is a little trickier than it seems. </p> <p> Each gear builds boost a little differently simply due to the fact that boost builds by "time" as much as engine speed. You need to be above some threshold in engine speed (<b>RPM</b>) in order to build any significant amount of boost. But you also have to remain at near full throttle above that RPM for some amount of <b>time</b> to build the boost you want. This amount of time changes based on engine speed too! </p> <p> So it's a big ugly cycle that's not as easy to dial in as it seems. You can get real close, real fast with some quick numbers. But if you want to really dial in that last bit of consistent boost tuning, it gets more involved. </p> <p> The tables provided in ECMLink are a reasonable compromise to a true model of turbo behavior. We may consider a different approach in the future that really takes into account how turbos work, but this will be less intuitive to the user (because it will involve time spans and decay values…things that are just less intuitive than duty cycle and RPM). </p> <p> So for now, we'll stick with the same implementation that Mitsubishi settled on for their boost control logic. But you have to keep in mind the limitations. You will likely see some overshoot in some conditions. For example, if you dial your tables in while doing flat road pulls (our suggested procedure), then you can expect some overshoot when you are actually doing a hill climb instead (slower acceleration rate). </p> </div>