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Finally going to start tuning EBC. I read through this ADJ's Quest but am at a bit of a loss on which FW version all this pertains to:
1) Is there a difference in methods or results between 1.4.1 and 1.5.x?
2) Do I start with Open Loop and then transfer, or does the Closed Loop Set-up mode make that approach obsolete?
3) Is there a thread that I have missed?
4) I presume that Jason's approach to throttle vs boost target is still valid.
Now I found this, which, though it may say what the manual says, makes a bit more sense to me: ADJ's Answer
Originally Posted by aidandj
Also, set your min and max duty cycles. It will help the loop by having a smaller range to work in. Start at a low duty cycle and increment by 5. Then you start getting earlier spool that is your min. Your max is the opposite. Start at 100 and lower by 5 until your spool slows down.
@aidandj, when you say getting earlier spool, do you mean:
A) At 3500 RPM, punch throttle and see how many mS it takes to get to, say 180kPa?
B) At 2000 RPM, punch throttle and see where the boost threshold (crosses above 100kPa) occurs?
C) Something else that I'm still not getting?
Thanks.
Last edited by DNMakinson; 02-13-2017 at 07:22 PM.
#2. Start at 1500 go full throttle, record when you hit your boost target (careful, you will easily hit overboost this way). This allows you to get a dynamic idea of what the lowest duty cycle that will affect your spool.
Think about it this way. The code will hold the duty cycle at your max value until you reach the lower limit Delta, then the control loop kicks in. The smaller duty cycle range the control loop has to work with the better off it will be. If I asked you to guess my number between 1-100 and 30-80, which would you be more likely to get right?
#2. Start at 1500 go full throttle, record when you hit your boost target (careful, you will easily hit overboost this way). This allows you to get a dynamic idea of what the lowest duty cycle that will affect your spool.
Think about it this way. The code will hold the duty cycle at your max value until you reach the lower limit Delta, then the control loop kicks in. The smaller duty cycle range the control loop has to work with the better off it will be. If I asked you to guess my number between 1-100 and 30-8, which would you be more likely to get right?
Well, I already know that mine will hit 180kPa very quickly at 40, so the 8-30 range seems likely.
This is where I am so far on 1.4.1 FW:
1) Set up Min Max, as you prescribed, Min = 10, Max = 40 (I recently reset down to 38, but that is hair-splitting).
2) Generally have the bias table and target table set up.
3) Originally set max boost to 180kPa in the targets with Boost limit at 185. I could not leave it there because I hit the overboost so much even in closed loop.
4) To try to be able to set "Basic" CL control, as seen in the image, I set top rows to 160. This allows me to not have so much power that the controller reaction can be seen. But what I'm getting, is that with slider at 350, seemingly no controller reaction. The Boost Duty just sits at the bias settings.
5) Unless coached to do otherwise, I will try slider at 500 (max), and targets to 170 and see what happens.
6) In ADJ's quest, there was a time that he reported that slider to "0" was too much, so the FW guys toned it down.
Questions:
A) Did they go too far reducing Slider Sensitivity, or is there a bug or bad setting?
B) Should I just go ahead and go to Advanced?
C) If I go to Advanced, is the slider still going to have no effect?
May I ask why your boost target is higher at 80% throttle than 100%?
Yes, for testing. When goal was correctly set higher, at 100%, two things: First, I kept hitting over-boost. I have not dyno'd at such a high boost, so I don't know where I am yet; Second, time at high boost is very short, so no time to determine when I get to oscillation (which, as I stated, I have not gotten to yet).
Here is a snapshot of the non-control in "Basic" mode with slider at 350. Same as the MSI posted above:
DNMakinson, from what I've learned your issues with holding target boost and overboost are probably related to your Boost Control Lower Limit Delta setting of 15kPa. From the docs:
Boost Control Lower Limit Delta - Boost pressure must be within this many kPa of the target boost before closed loop control will activate. Outside of this range the valve is held wide open (keeping the wastegate shut) for fastest spooling.
DNMakinson, from what I've learned your issues with holding target boost and overboost are probably related to your Boost Control Lower Limit Delta setting of 15kPa. From the docs:
Boost Control Lower Limit Delta - Boost pressure must be within this many kPa of the target boost before closed loop control will activate. Outside of this range the valve is held wide open (keeping the wastegate shut) for fastest spooling.
Agreed.
I am now at 30, and it is much more tamed.
Another thing I found. Do not use Boost Tolerance. Lifting throttle brings on overboots cut. There may be a use for it, but not that I can find.
EDIT: Also, I found that, in the end, I needed 65% for my maximum setting to truly keep the wastegate closed. And 10% minimum, as sometimes 13% is needed for actual control.
Here is today's picture of boost following target with throttle:
Last edited by DNMakinson; 03-20-2017 at 06:14 PM.
Reason: Added Log that goes with that Pic
I've been working on this also, getting good results...
Just curious what is the idea behind different boost targets at different TPS values? Being as i'm still tuning, I just have the whole table set to one value (150 right now).
I've been working on this also, getting good results...
Just curious what is the idea behind different boost targets at different TPS values? Being as i'm still tuning, I just have the whole table set to one value (150 right now).
So you have have linear throttle based boost. Half throttle, half boost, 3/4 throttle 3/4 boost.
One other reasons n: it reduces the amount of boost that is built, and then throttled. I other words, if at 1/2 throttle, you ask for your full boost, and get it in the manifold while dropping some pressure across the throttle, that is inefficient and hard on things. But if you don't ask for full body until you fully open the throttle, that is more better.
This is of none effect after 70%, because a throttle valve has little effect on flow between 70 & 100%.
I found this over in the Megasquirt Support Forum...The last few posts on page one are especially interesting. PID values can go up to 200. I was just assuming the max was 100, but really that is the mid-point.
Basically they are saying "Using a smaller delta and higher PID numbers will help it reach and stay on target."
I was having the same issue as this guy, where it appeared to work well in the lower gears and not as well in the higher gears...
Thank you for sharing this, I thought I was going crazy with PID #'s in the 150/100/100 range and still seeing lazy duty reactions. I'll try ramping it up and see if I can finally get rid of the boost drop off I've been fighting.
I've been fighting with this as well...
My situation is aggravated by a 2000ft elevation change and usually a 15degF drop in temp during my drive home.
Everything is within ~5kpa of target at 70degF, but as I get closer to home it shoots into overboost.
I believe the manual still states the P is back asswards with 0 being the highest coefficient and apparently 200 the smallest?
Good to know that 200 is the lower (or upper?) limit. I'll start venturing into that realm.
02-13-2017, 04:03 PM
Preferred Method of EBC Tuning MS3 1.4.1
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