I feel like this is a very common question and wanted to share how I decide how much boost is 'safe' on a me7.5 1.8t. Not only on the k03 but any turbo.

 I found a k03 compressor map and graphed rpm across it. Assuming 90% volumetric efficiency across the board. (Haven't bothered to find real values)

 

Note that after 5k rpm you are off of the compressor map. This means that the turbo is using the majority of its power to create heat rather than move air.

From there I just input the values of the max pressure line into kfldhbn. The ecu then compensates about 10% under those 'max' values and limits load accordingly. You can log 'charge limit for turbo protection' to see this in effect.

Things you would always want to log as you increase boost would be intake temperature (watch what happens after 5k rpm) and either maf voltage or mass airflow. Increase boost pressure until airflow stops increasing.

More boost does not mean more airflow!!!

More boost does not mean more power!!!

Would you plz explain how too read and understand a compressor map?
Use yours as example with axis and mening.
Thanx.

ECUxPlot will plot calculated P/R vs volumetric flow

Unfortunately, the P/R calc is rough; it doesn't take into account the various pressure drops accurately yet, but it is in the ball park.

Hi,
are you sure this is the correct map ?
I am pretty sure that 1.8t engines used 2072 compressors.
There was an article published in MTZ about the 225hp engine in which the compressor maps of the standard K03 and the K04 were compared.
See http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=527706

buergi

No I'm not positive.

Yea if you have a better intercooler you can push a little harder. I don't like that approach though. Definitely you have to log and see what's happening with your whole setup together. Like I said. As long as air flow is increasing then you are fine.