Newbie Boost Control Set up questions...

[hobieboy]

Hi,
I am getting ready to set up MS3 to also control boost and have a few very basic questions. I tried to do a few different searches & scan through the setup manual but didn't find the info so hope I can get some help here. I am using boost controller from DIYAutotune and will be connecting it in the 2-port waste gate set up.

The questions:
1) If I configure MS3 to use Normal polarity, does it mean that high duty cycle = more boost going to the top port of the waste gate thus keeping it close longer?
2) The controller said it operates in 19.5Hz - 40Hz frequency range. In TunerStudio, I can select 19.5Hz, 26Hz or 39Hz slow solenoid frequency. Will higher (39Hz) frequency makes the boost controller more responsive than slower frequency?
3) Boost Control Lower CLT setting in TS: it says that boost control will not work below this threshold. Does it mean that it will not activate the boost controller so one will essentially not build boost at all (or govern by the WG "natural" spring/boost rate)?

thanks!

[nathaninwa]

The hz range is valve dependent. Operating it to quickly won't let it close long enough to control boost well. I run my valves at 26 and 39hz, with no real reason with choosing one or the richer

Yes, more DC should give more boost, like you said, letting more pressure bleed into the top port

And correct on the coolant. Boost control will not b active below that threshold and will run on spring pressure only. Be realistic on the boost setup and watch where your at. My buddy has his turning on at 160*. At the strip he started the run at 154 and finished at 159. He could figure out why boost wasn't working!

[hobieboy]

Thanks!

Is there any suggestion of what I should set the initial open loop table defaults to be?

Would something in the 10% at low RPM/TPS area and 75% at the high RPM/TPS area be a good starting point to test?

[nathaninwa]

DC is per setup delendant. Weight of the car, spring pressure, cam and intake, they all work together. I would start on the open loop table at 10% everywhere and make a hit, look at the data, then add 5% at a time till you see boost overcoming sprit pressure. Now you have values to work with

[hobieboy]

Great & thanks for advice. Will start with that... when I get the car running

[hobieboy]

Finally getting around to adjusting this & have a few questions...

Is there a limit on Maximum Duty (in Boost Control Settings menu) that I should use; similar to "don't run injectors beyond ~75% duty cycle? I put in 60% right now but to get to the boost level I want, I am already at 55%.

My next step is to enable close loop. First question is: is there a rule of thumb for setting Boost Control Lower Limit Delta? I am thinking 10kPa.

I am trying to understand how to set Target Boost level - is this done via enabling Setup Mode in that I'd simply make a few pull so that the bias table is automatically set up then switch it to Basic/Advance Mode to truly activate close loop?

[Matt Cramer]

Boost control solenoids are designed for continuous (100%) duty cycle; they're not like injectors.

The target boost level is simply how much boost you want to run. The bias table is how much duty cycle the MS3-Pro should start with to give you that much boost. It then uses PID to adjust the duty cycle if you don't hit your target.

[nathaninwa]

I have found the delta for me to be 20kpa. This doesn't overshoot my target when ms switches from 100% to your boost dc

Like Matt said, you can run valves 100%, some say 10 to 90% on them. If your getting into the 90's it might be time to run a little larger base spring

Tune the bias table so you flatline your target. If it's 200kpa, then the log should hold that till redline. Adjust the bias table to make it so. Setting up pid is like ego correction. Ms uses the bias table all the way through as a baseline and makes decisions based on current conditions

Honestly, I'm still running setup mode 2 years later. The bias table is hitting my targets so far with no correction

[Dennis930]

Hobieboy,

Set your lower delta to 40 or 50 kpa to start. Be sure to setup your overboost limit and spark cut/fuel cut settings. In closed loop basic, the code keeps the boost control valve @ 100% or 60% in your case until MAP is within 40 or 50 kpa of your target boost level. It then applies the DC value from the bias table for the particular RPM and boost level to boost control valve, then applies PID control based of the slider position (sensitivity). Use setup mode first, so no PID is applied, to tune the DC values in the bias table at various RPM's and MAP levels. You will have to make several pulls while datalogging boost DC, target boost DC, MAP and RPM's to see how boost DC affects boost levels at various MAP and RPM points. Then edit the values in the bias table to close in on optimum DC for each MAP and RPM bin. Once you are dialed in, you can switch to basic mode and see how everything responds. Adjust the slider if needed to help reach target boost quickly without hitting your overboost limit. Then you can lower the delta KPA to 10 or 20 kpa. If needed, then the individual PID values can be tuned in the advanced mode.

[hobieboy]

Thanks Matt, Nathan & Dennis... Just to be sure, it is the boost control Bias duty table and not the boost control duty table that I should adjust? The bias table defaults to 100 for all cells to start with so I can start with what I observe in the open-loop control duty table & set as starting point.

Based on the feedback here (& Matt knows the EBC I am using ) I'll change the Maximum Duty to 100%

[nathaninwa]

The boost duty table for open loop should be grayed out when in closed loop setup mode and only the bias table is active. You can use open duty numbers that work with the boost targets your after in the bias table

Up duty to 100% and you'll be golden

[hobieboy]

Guess I really don't understand how the bias table works. I essentially transferred the boost duty table numbers to the bias table but boost duty now only goes up to 31% instead of 55% (I have manually increased the bias table from 55% max to 75% already) when I was using open loop. So now I only get 2/3 amount of boost than open loop.

Did I misunderstand how the bias table numbers should be set up a.k.a. these numbers represent the duty cycle?

My current msq is attached.

[nathaninwa]

The bias table is an open loop style table per boost target. So if your boost target table has 200kpa then megasquiet is only using the 200kpa row that you have created. You'll tune this row till you flatline 200 throughout redline

While in setup mode the code uses 100%dc until the delta before your target. Meaning a delta of 20, will yield 100%dc till 180kpa then MS uses the bias table values based on rpm

Once the 200 row is tuned, you can move onto 220 and repeat

This way closed loop only needs to correct day to day changes slightly

[hobieboy]

Thanks for the explanation Nathan. A little slow...

So it means that if, for example, I determined (from open loop table) that 60% DC at 4000 RPM will yield 200kpa then I should put 60% at the 200kpa row for 4000 RPM in the bias table. In this case, MS will use 100% DC until 180kpa (which will likely be below 4000 RPM) then look at the 200kpa row & switch to use 60% DC?

What is the difference in how MS operates between Setup & Basic? Is Basic = use the sensitivity number to set the target boost only?

thanks!

[Matt Cramer]

Setup turns the PID off entirely so the duty cycle you get is the duty cycle in the bias table with no correction. Basic uses PID correction but the only tuning for the PID is the slider.

[nathaninwa]

Thanks for the explanation Nathan. A little slow...

So it means that if, for example, I determined (from open loop table) that 60% DC at 4000 RPM will yield 200kpa then I should put 60% at the 200kpa row for 4000 RPM in the bias table. In this case, MS will use 100% DC until 180kpa (which will likely be below 4000 RPM) then look at the 200kpa row & switch to use 60% DC?

What is the difference in how MS operates between Setup & Basic? Is Basic = use the sensitivity number to set the target boost only?

thanks!

Your example is true. 100% till 180 then switch to the 200kpa row on the bias table. If 60% makes more than 200 then take some out, if less than 200 then put some in. Setup mode is just that, it's a setup phase letting you run open loop style values with the 100% spool up that closed loop offers

[hobieboy]

With much better understanding of how the tables work I finally got close.

My #1 mistake was... I didn't put anything in the boost control target table Now that I filled that in, really not sure how could I ever have missed that.

So onto enabling Table Switch for different boost level now

[hobieboy]

Apologize for another newbie dummy question...

If I enable Boost Table Switching, say using TableSwitch pin, then when this pin is "active", MS will switch to use Control Settings 2 & associate tables?
So I also need to first turn ON Boost Control Setting 2?

Did I get this right?

thanks!

[nathaninwa]

Iirc you just enable table switching and boost target table 2 will become active. At this point you'll still use bias table 1 to set duty cycle while on boost setting 2

[hobieboy]

Iirc you just enable table switching and boost target table 2 will become active. At this point you'll still use bias table 1 to set duty cycle while on boost setting 2

Umm... then when will bias table 2 be used?