Thanks Jordan

That’s what I’m trying to get my head around. I’ve got the log including WGDC but do I ‘load’ that like for like in KFLDIMX?

In other words, load 95% at 2000 rpm, 95% at 2500 rpm, 75% at 3000 rpm and then 50% at 3500 rpm, 50% at 4000 rpm, 50% at 5000 rpm and so on.

Or is it more a question of 50% at 2000 rpm, 50% at 2500 rpm, 50% at 3000 rpm, 50% at 4000 rpm 

I’m going to try reducing the 95% values (1000 rpm – 2000 rpm) but I’m guessing and would like to understand a bit more.

I really don't follow you here.

From NefMoto Wiki:

This would indicate that the values in KFLDIMX represent where you expect WGDC to settle once request meets actual.   The factory has KFLDIMX tuned in a way that allows (even promotes) overshoot.  I don't see how KFLDRL relates.  KFLDRL is a representation of how a specific model of turbo will act, no? It's not something you'd want to calibrate on an unchanged turbo, right??

Thanks
-Jordan

I understand that, but it doesn't mean KFLDIMX is right from the factory and it definetely doesn't work for increased boost. I get it, you can't just log WGDC and plug it in to KFLDIMX. Tommorow I'm going to look at KFLDRL and adjust my logged WGDC values based on what they would be in KFLDIMX if they weren't  impacted by KFLDRL. I'll bet you the factory isn't even close.

Hi all,

Thanks for the responses. I’ve been looking into this a lot and it’s really interesting to see what you are saying.

I’m sure you guys will recognize this

http://nefariousmotorsports.com/forum/index.php?topic=2985.msg29152#msg29152
http://nefariousmotorsports.com/forum/index.php?topic=517.msg3902#msg3902

Rightly or wrongly, here’s my observations. Comments welcomed !

Steady State (by this I mean actual matches, or is extremely close to, specified)

1)   The output of the PID controller is the sum of P, I and D . The error (difference between actual and specified) in the steady state is zero, meaning actual matches specified and the PID doesn’t need to adjust anything. Since the error is zero, the contribution to the PID from P is zero as well. But if all the contributions (P, I & D) are zero then the output of the PID is zero as well. Clearly we need the output to be more than zero otherwise we’ll have zero WGDC and no actual boost. So even in the steady state, although the contribution from P is zero the contribution from I is NOT zero, in fact it should be the exact amount to ensure enough WGDC so that error is zero, actual matches specified and the PID has very little to control.

2)   The I component is an accumulation over time, from when the loop started to the present time. We want to regulate this so it doesn’t just get bigger and bigger, leading to a larger output in the steady state, in turn leading to more WGDC, actual diverging from specified, error increasing and the PID has its work cut out to balance this.

So in the steady state I believe KFLDIMX stops I from getting bigger and bigger and also sets a sensible value for I, so that the PID does fine rather than coarse adjustments.

Initial Ramp-up
I don’t think I have an issue in the steady state. My actual tracks specified and doesn’t oscillate around it. My issue here is that initial overshoot. In the ramp-up the error is large and P, I and D will all contribute to the output of the PID. Maybe I’m looking at the wrong area of KFLDIMX and should be looking right on the left of the map, before I get to the rpm range where steady state is?

I’ll also define KFLDRL and take a look.

Factory want a boost spike. Boost spike is good, it gives midrange punch and overtaking ability in a 4wd car

Rick

The NefMoto Wiki is wrong. The FR is right.
Very easy. I have said it many times - do not read what someones interpretation of the documents is, read the documents.
Else it is just like usual forum cr*p. Someone says something and everyone repeats like sheep, even though it has little to do with reality.

Read LDRPID in the FR with an open mind. Forget everything you read everywhere else, most of the stuff people write on wikis and forums is just their interpretation of things, it can be wrong, omit details etc. Why rely on it when you have the functional document of the ECU telling you exactly how things are?

1) The FR does not mention methods for tuning the PID near the MAP limit.

2) The FR does not mention that the setpoint can exceed the MAP limit due to a design flaw in ME7.

3) The purpose of wikis and discussion boards are to discuss things, and to (collaboratively) come up with interpretations (for forming consensus) of existing documents whose authors are unlikely to be around to answer questions, fix errors, address limitations, or clear up misunderstandings.

If you truly think there is nothing of value outside the FR, then what is the point of any discussion of anything?