So I have been reading and studying the maps, and things get way more clear now. However, two things still bother me, I will first ask about just one, the second one I still have to think through.

The calculation of and/or the source of the base duty cycle for the boost valve operation. (Let's put aside PVDREG which is a PID controller for this, but it has to start with some duty cycle).

There are three modules that seem to use fancy models to get the DC for the boost valve:

BGHATLST - calculation of the actual waste gate opening angle
BGHATLSTS - the desired one
BGLDRSTG - the DC cycle resulting from the two above

and then there is the one module:

ATVLDSTE - Output DC boost pressure valve

which essentially gives out the DC out of pedal position / RPM map.

What is the relation of the two things? Is it an open / closed loop difference and these two are used interchangeably? Or what? The first three use turbine and compressor efficiency tables among other things, I wonder how crucial is all this to be calibrated when changing turbos. Or is it enough to just modify the DC cells of the corresponding tables (KFTVLDST in ATVLDSTE and TVLDSTDPW in BGLDRSTG)?

(Please do not ask me why I need to know things far ahead of doing a simple stage1 tune, this will not lead anyone anywhere, I have the urge to learn this and understand, the more I know the quicker the rest goes).

Yes, PID is in the PVDREG module. Pointless as it may be (I believe you), these three modules are run over by tractor in two different factory setups for the same engine with a slightly different turbo, so I wonder what's the game here. I know from my previous experience that in the end the basic DC is what really counts, how you get to it is irrelevant. And the basic DC can far off, the character of boost build up is such that the PID has to deal with large errors to start with. (I also wrote my own EBC procedure and PID controller for two different ECUs, and neither had to be so complicated to give spot on boost control results).

Going through all this I realised that this ECU has a lot of similarities with MED17, just I couldn't find FR for that one either (not for free anyhow).

Would you be able to give at least some indication what was causing it? Did it have something to do with pressure across throttle blade raising a lot (close to equal pressures) and KLAF correction reducing the flow figure for the desired throttle opening table?

Asking this because this is my next concern (that I mentioned above, but had no time to dig into). Namely, it seems that this ECU does not open the throttle a lot at high boost, all the regulation is done with boost control rather than throttle blade. This seems like a waste of potential power. (I do understand that controlling load through boost regulation might be easier / smoother, still). Now, I am (for now only theoretically) wondering what happens when you tune these tables such that the throttle will open 100% at high boost. What else will get totally messed up in the calculations, like to pressure ratio getting very high, etc. etc.

And did you mean 100% of throttle, or the pedal?


Yes, I do work with the Esseesse file a lot and compare it to the base 155hp version (which is based on the same program code, so the maps are in the same places, makes life so much easier). When you say overboost in this context, it is confusing, 180hp version does not have overboost to speak of, the two load maps (regular and overboost) are identical, this is normal boost for this car. See the attachment.

But I am yet to find a proper OLS or other definition for this family of ECU maps (180 hp version or its 155 base). This one has some maps that are not in the 135 hp version at all. Some of them I identified (for example, all KFPED-s and KFZDAHS-es are all present in double, one version of manual and one for automatic), but some of them not. If anybody has such a (complete) definition and is willing to share, you know where the PM button is

Oh, OK I missed the fact that the problem was with MBC, I thought you had it with factory EBC, just raising the boost through maps.

You are wrong about KFPED maps on the Esseesse program - there are 10 (!) in total, 5 of what you have normally:

normal
low speed
normal sport
low speed sport
reverse

and 5 more of the same, but for automatic gearbox. This is so more interesting because of the fact that the reverse map is described only to be for automatic gearbox cars, why there is a need to have two, beats me. The same for KFZDASH-es. Figuring out which one belongs to what is not that straightforward

As I said somewhere above, I am nowhere near trying things out on the car, and in the meantime before I reach that point I want to understand and collect as much knowledge as I can.

That's the whole trick with ME7.9.10, it can. The Esseesse version we talk about above has MAP sensors upgraded to 3bar ones, and the ECU is properly calibrated for that, starting from the sensor input conversion (sensors gradients and offsets), ending with the pressure limiters here and there raised from 250kPa absolute to 300kPa. This is one of the reasons why I do not buy the advice of the sort - "Study the other ME7 ECUs and everything will be clear". It won't in many cases, and this ECU, despite its name, seems to more like MED family (which I also know little about). Plus this extended program version of the Esseesse version that has maps that have no known definitions...

There is a desired boost diagnostics field in Multi ECU Scan, but I never tried it.

Since I will not have time to do any test anytime soon, I have to rely on what I see in the definitions and what I know about the ADC in this ECU. Also, I own the small version of this engine with factory boost settings, which hardly reaches 0.9 bar, so I will not see much anyhow. But:

The gradient for both MAP sensors is hex 0x8740, on the Esseesse version with 3 bar sensors it is 0xA4B4, and I do not see why it would not be possible to go up with it more. Divided by 128 that gives respectively 270 kPa and 330 kPa range, subtracting the dead border voltages of the sensor gives the ranges I would expect of 2.5 and 3.0 bar. All conversions (not for baro pressure and basic boost pressure) in the map definitions are X/128, which gives 511.99 kPa range precisely. So unless this is all wrong and so is the diagnostic program (which also uses X/128 conversion for the boost pressures, desired and actual, this I know, I mean the conversion it used, I have not see the reported values) then I do not see what you are hinting at? Yes, I read the S4 tuning wiki and saw this: "All pressure values in ME7 have a fixed (internal) limit of 2559.96 mBar (0xffff/25.6)". But I do not believe this is the case here, at least not for all the pressures.

There is one thing that is puzzling though, the conversion in the diagnostics program for the intake pressure is X/256 indeed. And probably that's something I should indeed check.