are you a diesel guy? turbos will still push air thru the surge line, and past the top righthand side of the map, just not as efficiently, and really hot

 

high boost = high iat's, thus the need for interheaters

 

That goes beyond IC territory lol. When you go that far off the map you'd better have some serious meth/water injection going on and a water/air cooler. :P

 

Most of the time, when you get to higher pressures it drops down considerably. Basically what happens is there is generally one PR where the turbo flows the most air. So even if I'm running much higher pressure than that, once that PR is maxxed out flow wise, the pressure keeps dropping as the compressor can offer more air flow at lower PRs.

Using the above comp map. If I ran 3.5PR, I'd run out of airflow at around 48lb/min. So let's say my engine wants to keep making power, well the pressure will drop down to around 3.0PR so it can flow the most amount of air possible.