Quote:

---

Crap! I totally misread your question. Since I typed up all that garbage I'll leave it for the lurkers to read.

Boost is read as PSI. Pounds per square inch.

Inches of pressure usually refers to inches of mercury which is a much older way of measuring things.

---

My N/A airplane had a manifold pressure gauge in it, it is the same as a barometer with the engine shut off, it will read the actual outside barometeric pressure in inches, IE at mean sea level in instrument standard conditions(29.92 at 59 F at MSL))it will read 29.92, at 5000 ft with the same barometric pressure it would read five inches less due to the loss of pressure at the higher elevation, one inch per 1000 Ft in standard conditions My question is is there any colilation(SP?) between manifold pressure and pounds of boost, IE is 6 lbs of boost equal to or close to 36 inches of manifold pressure? N/A airplane motors with a manifold pressure gauge will read at or close to zero at idle, the more you open the throttle the more manifold prssure you will see, at wide open throttle on take off it will read the outside barometric pressure The supercharged or turbocharged airpalne motors will have above the outside B.P. at take off power IE above 31.00 inches all the way up to or above 44 inches of manifold pressure depending on the throttle position and RPMs Canton,