hack/ experiment press range of MAP sensors?
My understanding is that a 1 bar will read from 0 to 14.7 psi, absolute. So from 0 to -14.7 psi gauge at sea level.
The sensor they show in that link goes to 2.9 psi absolute, which is about 24 inhg of vacuum. A map sensor would go all the way to 0 abs, or 29.92 inhg vacuum.
A two bar can measure from -14.7 to 14.7 psi gauge, and a three bar from -14.7 to 29.4 psi.
The scale remains the same for all sensors. Full sensor voltage (typically 5v) at 0, and 0.3v at max pressure (least vac). I have no idea how linear the scale is though.