Ok so we hit the ground running pretty hard with fueling.  I’m sure I have missed things that I will add to this thread later on in my learning but for now this is what it is.  So we have an internal combustion engine.  We figured out fuel but last time I checked you need fuel, air and spark to make this puppy purr.  So let’s move on to understanding air and in this case boost as we got those big snail looking things that make us go fast.

First things first we have to gather an understanding of how ME7 actually measures boost pressure because I am sure there is a lack of maps in your file that have anything to do with PSI as you would normally see on a gauge.  There are very few maps that even convert to mbar, so now you’re scratching your head saying well then what the hell do they use to measure boost pressure and how do they limit it?  The ME7 computer is… a freaking computer, it’s capable of more calculations per second than you or I or even a group of 200 could complete in an hour.  It uses a term called “load” to calculate, control and cap boost pressure.  In the ME7 system boost roughly equates to load.

In an edit by gman86 he has described to us in more detail what the load % that we are seeing in our maps actually are.  "The one key correction that should be made is that load isn't boost. It's cylinder filling. When requesting a cylinder filling value above what can be achieved by the engines own VE (volumetric efficiency), the ECU will use the turbocharger to assist. Load can result in varying boost pressure depending on various temperatures and external pressures. Therefore it's not safe to assume that x% load will always result in y% boost pressure." What I have gathered from this edit is that depending where you are in the world the values in your load tables can change dramatically.  Depending on the atmospheric pressure where you live and the temperatures in which your car normally operates under. You should take these considerations into account when adjusting your load maps and not borrow from someone's file half way around the world.  Small changes and logs are one of the key points I am trying to get across.

Let’s take the first map that I would like to discuss LDRXN.  LDRXN is loosely described as the maximum allowable load.  People use this map as the main request map for boost which is dependent on rpm.  The table’s values are displayed in load percentage.  This is maximum permissible load the ECU will allow.  There is another map that looks very similar called LDRXNZK.  This map is the same as above except only applicable under the condition of a continuous knock.  It will pull load to prevent you from damaging your engine when the engine is experiencing a continuous knock.  I see some tuners copy and paste their LDRXN to the their LDXRNZK but I wouldn’t think this is the right way to do it.  I would much rather scale back the whole table back to either stock values or a lot less across the board than your maximum permissible load (LDRXN).  You have a few other maps too that are made to limit boost pressure so you don’t overboost to high hell or deviate from the requested load.  The first limiter that I came across in my reading was KFLDHBN.  This is the absolute pressure ratio which will also limit how much boost pressure the me7 system will allow you to achieve.  From what I read the way to calculate the contents of this map is to take the value and multiply by atmospheric pressure which will give you the max absolute manifold pressure. I.e if one of the numbers is 1.8 in the table and your atmospheric pressure is 1000mbar then multiply 1.8 by 1000mbar and you get your absolute manifold pressure which in this case will be 1800mbar which is 800 mbar (subtracting atmospheric (1000 mbar)) and converted to psi would be 11.6 psi roughly.   I hope this is making sense and I haven’t lost anyone. 

Now we get to the most fun part of the conversation! The elusive KFMIOP and KFMIRL maps that everyone seems to go bat shit crazy over.  In the motronic me7 system everything works in tandem with each other.  Every map is there for a reason and interventions occur to protect you… well mainly your engine.  I’m sure we have all heard the term torque intervention at one point in our readings.  There is two levels to torque intervention (that I know of!) the second being the worse of the two as I have heard it is something you don’t want to happen.  Now from what I have gathered torque intervention is something that happens from time to time (level 1 at least) but you can prevent yourself from hitting these interventions too often by taking your time making small changes to KFMIRL and KFMIOP and understanding that when you change one you should also change the other as they, like many maps, work in tandem with each other. 
 
This is a post by Phila_dot  is worth mentioning here. “(KFM)IRL has NOTHING to do with IOP.  KFMIRL takes an input and converts it to desired load.  That’s it.  You are good as long as the torque value at the current load and RPM is below the max allowed for the current pedal position.  There is absolutely no need to touch anything near the idle areas”.  Do not misunderstand what he is saying here as you still do need to make changes in IOP when you make changes in KFMIRL. 

I will not get into detail about the modifications of KFMIRL and KFMIOP because I am still experimenting with these maps and don’t want to spread misinformation.  I am sure there is more than one way to skin the cat.  Remember the less you have to change the better.  Don’t change more than you have to! There are also calculators such as ME7 wizard that serve to calculate theoretical KFMIRL and KFMIOP maps for you as well so check those out!

This is a response just recently from nyet!

"Basically, the only question is if "actual" torque is under safe limits, not if it doesn't exceed requested torque."

That said, if you "Make sure that the increased resulting load (when fed into IOP) does not result in torque higher than the torque that generate that load in IRL.", you should never see torque intervention.

Thanks for the input Nyet! It is much appreciated.

Another map we can take a peak at would be KFTARX which definition is “Intake Air Temp Correction Factor for Specified Load without Knock”.  This definition will aid you in understanding its function.  A lot of the time I see tuners set this table to all 1’s which effectively disables the correction from occurring at any intake air temperature.  This is how I see the majority of tune files and was a recommendation by TTQS at one point in time.  There is also a similar map called KFTARXZK which nearly the same thing just taking into consideration there is a continuous knock occurring.  I’m sure some of you have mustered together that the ZK generally is a map name tag for instances with continuous knock (or so I believe). There is a third map I have noticed in my file similarly named KFTARXB which I imagine is just another set of correction factors dependent on a certain condition but I have yet to investigate that map further.  In any event many tuners set every single one of these to 1 across the board.
Further, we have LDPBN which seems to be absolute maximum pressure limitation when motor temp is too high.  In my file all these values are set to 2550 which is the maximum boost pressure the me7 can read and control from what I have further read. 

There are further maps (other than KFLDHBN) that I have noticed so far that have to do with overboost protection.  The first being LDORXN which is the maximum permissible load during an overboost event.  This map is activated by another called TLDOBAN which is the activation timer for an overboost condition.   You also have a third map, KFDLULS.  KFDLULS is the maximum deviation of boost pressure for overboost protection enabling.  In laymen’s terms this means this is the maximum allowable difference between requested pressure (measured in mbar) and actual pressure. This map, according to the s4wiki, should not have to be touched if you set up your boost/load maps properly (I can 100% agree with this statement). If you have to max this table out you will most likely be purchasing a new turbo or engine in the near future. I imagine if the boost pressure deviates past the value in this map it will trigger a limp mode protecting your turbo as well as protecting your engine from losing its cylinder head.

So to recap we have KFMIRL, KFMIOP, LDXRN, LDORXN, LDXRNZK, KFLDHBN, KFTARX, KFTARXB, KFTARXZK, LDPBN,TLDOBAN, and KFDLULS so far for load request, control and caps.  There are a few other maps (mostly timers/time until intervention of overboost) that I have seen other tuners tweak to prevent the ecu from triggering an overboost condition.  I will not include these maps because I think this is the wrong way to do things and don’t want to spread bad information.  If someone agrees with increasing activation time of an overboost condition please feel free to share why, I am curious on this point.

As always please someone correct me if I am wrong on any of these points.  I am very new to my understanding of ME7 and would love to be torn to shreds so I can build myself up all over again!

BTW thanks for your attempt to summarize things.. there are a few other things I could nit pick on, but in general, you have the right idea...

I'm certain prj, though, might be very upset at some of those things, so just a heads up... if he shows up, don't take it too personally.

Did you mean to say requested torque for the underlined text? Sorry just want to get a good understanding of your responses.

ok great 

I eagerly await! Thanks nyet

I will integrate this understanding into the texts above!  Thank you very much for your input gman

Thank you! I have been busy logging some of my first tests on 1.8t cars and vr6 cars so I have had no time to expand.  Please, if you see any issues with what I have written let me know and I will be happy to correct