Because in the 22 yrs I have been doing it that way you never run out of fuel volume at any boost level and the temps are nowhere near what you think..
FYI, EVEN KTM is now using MY technique on their mx bikes to operate the ex valve !!! with nothing more than 1/4 inch vacuum line !!!!!
Many thought the heat would be an issue.. Now even the OEM knows its not..
Once you understand the relationship of fuel delivery Before boost build you'll get it..
Its NOT mandatory, many still get along fine using the airbox .
For higher boost longer duration pulls on the hammer you damn well want fuel pressure 10 psi over boost.
When you try it, and see that your engine runns the same, you then can surmize the fact that even at the higher pressure you still have NOT overcome the demand for fuel and its not flooding out ?? tells you you still need more to be safe at the 30 [si plus level.
I used this method in the 1988 selds and it was the END to all fuel handling issues.. you can run your base pressure at 2 psi for clean response on and off the throttle too..pipe pressure should be 3-5 minimum over boost, so fuel pressure will rise in advance to boost and will be that same 5 psi over your base.
In my applications for drag racing and speedruns we see 12 -14 psi fuel pressure over boost and have @ dynotech the smoothest fuel flow numbers EVER for a turbo 2 stroke !!! primative carbs they say !!!!! LOL still doing exactly what we tell them too...
....
he has all the current he needs to run it like the doo carbs directly from his 12 v dc charging lead..
i could be wrong though as I am no polaris pro tuner for sure.
Gus