To follow up on this I will go through some maps and try to explain some things that are modified for the persons that are interested, the general principle will apply to most diesels but while some things my be similar on petrol there are also a lot of differences.
If anyone wants to have a look they can download the free demo version of WinOLS software and have a look at files themselves. It's probably the most used and most versatile soft available. They have dialled back demo soft somewhat these days and limited functionality. In earlier days you had a lot more functioning demo soft that only did not allow to export finished files but since people found a way of extracting files the limited other functions in demo. Anyway still a great soft.
https://www.evc.de/en/download/down_winols.asp
The first thing I would like to address is where it all starts with the driver input at the pedal. So basically the ECU needs to translate the accelerator pedal position (learned position) into the torque value in case of EDC16/EDC17 or injection qty in mg in case of older EDC15. I will talk about 4.2TDI which has EDC16CP34 so it will be Nm.
There is a map or to be more precise several maps that translate pedal input to requested Nm, it could be several maps for normal, limp mode, reverse and so on. There can also be several blocks of the all the maps in the same ECU for different codings. For example my 2.5 TDI has 2 blocks depending on coding 1 for manual and 1 for auto but A8 only 1 block.
So if we have a look at main drivers wish map it has 2 axes of engine rpm and pedal position and and output of Nm. This is the stock map for my soft version in text and 3D. On the text version you have % of learned throttle going horizontally and rpm going vertically and the grid as the requested Nm depending of rpm and throttle position. This is only what the driver requests, not the actual torque that engine will be delivering as that will be limited by a number of other maps and factors. You can also see that it goes to 0 Nm at 5200rpm with the torque reducing rapidly from 4400 to 5200rpm. If you feel a bit adventurous and want to take the risks you could change that like I did on A6 and have nearly full torque up to 5300rpm and the a drastic cut from 5300 to 5500 rpm. The A6 does the rev limiter bounce like the petrols do and not the gradual fade out you normally get on diesels, but this will be affected by a number of other maps as well.
We can see that original map is already going up to 840 Nm so you do not really need to modify it if you do not want to go over 840Nm and you do not want to modify throttle response.
Now if we have a look at the modified files you will see that tuningfilewarehouse £15 file for my soft version 382247 goes up to 900Nm
and Swiftec version for soft version 392905 goes to 1000Nm
Like I said this is what the driver requests, not the actual torque engine will make as that will be limited by a lot of other maps and factors but if you don't ask you don't get.
I will address main torque limiter in the next post.