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CL Boost Control - is this normal?

 
Old 05-13-2018, 11:51 AM
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Default CL Boost Control - is this normal?

I've been playing around with closed-loop boost control for a while now (yeah, I know, what took me so long) and I think I've figured out most things (as in, "i's running good enough now that I'm hitting my target without oveshoot, and without going into overboost protection). But I've noticed something that I can't find an explanation for, in my searches on here, and on msexrta.

What I'm seeing is, under about 85kPa, the EBC stays at full closed duty (i.e. wastegate is full open). According to the info I've encountered on msextra, this "full closed" duty cycle condition is the default if Boost Tolerance is turned off (which, in my case, it is not) and that boost control doesn't kick in until you get above 100kPa.

My question is: Why is the Boost Duty in the log showing fully closed (at 30%) until the MAP goes over approximately 85kPA, at which time it goes to fully open (at 90%) - which I think is wrong - until the MAP gets to 35kPa below the target boost - which is what it's been told to do.

Here's the log;


...and here are my Boost Control Settings;
Attached Files
File Type: msq
CurrentTune - rwyatt365.msq (119.3 KB, 17 views)
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Old 05-13-2018, 12:58 PM
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You might want to consider updating FW/TS. It looks like you are on an older version where these settings are less intuitive. Your screen shot should also be sized to include the trace labels.
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Old 05-13-2018, 01:17 PM
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I'm using TS v3.0.28 on a mspnp2 (not the best, but it gets the job done...kinda). and here's a better screen shot;


Right at the cursor position, Boost Duty has jumped from 30, to 90 in one step. The corresponding MAP values jump from 82.4, to 92.8. Throughout the log (not attached, but I can supply it) the pattern repeats itself...below 80-ish kPa - 30% duty cycle, above 90-is kPa - 90% duty cycle (until it gets to target boost - Lower Limit Delta.

Something else curious I discovered in playing around with the Target Table; if I set the lowest value in the table (lower left-hand corner - 0% TPS/1000 RPM) below 80kPa, the car won't start. Looking at a log for this, it's because the PW is zero!! A little bit to looking at logs shows that the MAP value during cranking is 80kPa. Coincidence? I think not!!

That raises another question; Why would the Boost Control have any effect during cranking?
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Old 05-13-2018, 01:45 PM
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Turn the boost tolerance function off. I always found this function to be less than desirable, even potentially buggy in older FW versions. I never went back after updating to test it out.
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Old 05-13-2018, 02:30 PM
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I'm not sure why it's shutting off your injectors, but you crank at 100kpa, which is over your 80kpa limit, but it should just keep your EBC open, vs. shutting off your injection...
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Old 05-13-2018, 02:31 PM
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Ah, yes you're over 15kpa above your boost target, so it's hitting overboost protection, and cutting fuel.
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