icantlearn

So here is the "backstory" on page 2-3: https://www.miataturbo.net/diy-turbo...3/#post1374584. read that

So, starting from where we left off, Ramensoop said, "Test mode is only used if you want to do the blow test to verify your valve is working. Otherwise you need to start tuning open loop as outlined previously or in closed loop setup mode."

Whats the difference between using test mode and setting my Max% to 0?

farpolemiddle

Aidan already answered your questions to a point. I was able to get basic settings off the few posts he and saving ton gave you.

ramensoop

iTrader: (1)

test mode will only verify that the valve is working and that the polarity is correct.

set min/max to 0/100

drive in open loop boost as outlined here

or

what i did was use closed loop in setup mode. set all boost targets to 140, then made 3rd gear pulls increasing duty in the bias table until i got 140. next time I go out i'm going to work on other parts of the bias table.
setting the target table is important because closed loop holds the valve open until within xkpa of the target for fastest spool.

as i was increasing the duty cycle i found 30 to be the first point to have any effect on the wastegate, so i will set this as min duty.

icantlearn

Ok awesome. I will try open loop on the way home tonight. Just curious, what was the difference is spool after you tuned the EBC? Also, shouldn't I set my min to 10 to begin with? Not 0? Or should I just go to 30 and see what happens?

ramensoop

iTrader: (1)

Min/max duty only really matters for the PID calculations for closed loop. In open loop you are telling the valve what to do via the duty table.

icantlearn

Yes but isn't this why I transfer the table over to closed loop?

aidandj

iTrader: (5)

I dont think you have a full understanding of how Open loop and closed loop EBC works.

Test Mode:
This allows for complete control over the valve duty cycle. You can confirm its working, and troubleshoot issues.

Open Loop EBC:
This follows the open loop table. I'm not sure what you mean when you say "Setting my Min to 0%"

This is an open loop EBC table:



There is a direct relationship between throttle position, rpm, and boost control duty cycle (not actual boost pressure). This is a simple method of controlling boost, you increase tune duty cycle to try and hit your boost targets.
The downside of open loop is that as conditions change the duty cycle required for different boost pressures can vary, which means that you will get different boost pressures at different conditions.

Closed Loop EBC:
This is a whole different animal. The closed loop target table has rpm and tps axis, just like open loop, but the z axis is boost pressure instead of duty cycle.



That table says to target 190kpa whenever throttle is 20% or above, and at all RPM.

The complex part about closed loop is how it gets to that pressure.
You can find the exact formula in the source code, but essentially what it does is looks at current pressure, and duty cycle, and makes adjustments to the duty cycle to try and hit the target pressure.

New in firmware 1.4 is a Boost Control Bias duty table. This gives the PID control a baseline to start from. The x and y axis are rpm and boost pressure, and the z axis is duty cycle. This lets you tune a bias curve into the PID function and helps it stay on track.

The Min/Max duty cycles are used in the duty cycle calculation in closed loop boost control. If you have them set to 0/100 then the calculation has a much wider range to work with, which makes it harder for it to zero in on the correct duty cycle. You are giving it a finer resolution to work with, and it keeps oscillation away.

I'm rambling now, but read the manual. It contains a lot of this information.

Megasquirt Manual Index - Megasquirt EFI