Loc,
I use the boost gauge to keep from overheating the engine when climbing a grade. As I ascend the grade I reduce the accelerator pressure and watch the boost gauge come down keeping it around 20psi. This helps to keep the engine from overheating. A little caution climbing grades in the summer really pays off in the form of a cooler running engine.
On flat land with c.c. set @ 65mph it reads about 5-10psi.
Hope this helps you. I plan to be in Houston April 4,5, & 6th. If you are free maybe we could schedule a test drive!
Tuga & Karen Gaidry
2012 Honda Pilot