I'm working on a little project where I want to calculate the boost pressure (in bar) which my turbo currently produces. I use a wifi OBD reader that I plug into my car. I saw mobile apps calculating pretty accurate values based on my internal sensors.
Now my question: Which values do I need for calculating the actual boost? I found this forum where one guy explains a Formula. He uses the MAP sensor and a barometric pressure sensor. However I don't know which PIDs they are represented with. Until now I thought the "MAP" sensor is the "intake manifold absolute pressure", but on Wikipedia this values goes only from 0-255. Looks like a pretty unprecise indication.
Can anybody help me identifying the proper PIDs so I can calculate my current pressure?
Thanks already in advance!