I see most boost/vacuum gauges have a split dial and show boost in psi and vacuum in Inches Hg. I suppose this is just the usual units for each measurement, but why not have both readings in PSI or Bar or?? Any gauges have this arrangement?
Hmmm! Funny. Do you mean the test meters, or original equipment installed gauges. Many aircraft units were in a single unit, most of them In. Hg. They read MAP, not gauge pressure. To me that is what such an instrument should show- a single scale reading zero at 29 inches of vacuum, 29 inches at ambient, and going up from there. Having never had a supercharged car, I have no experience with such installations, but don't see why they should be different than aircraft practice.
I work in a facility where they measure pressure in barrs, torr, millimeters of mercury, inches of mercury, inches of water, pascals, pounds per square inch, pounds per square foot, kilograms per square centimeter, and probably some other units that I can't think of off the top of my head.
Needless to say, the engineering staff is very good with conversion factors.
--scott
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.