[s-cars] Re: Blown Hoses, MPG's & Cloaking Device Failure

[Michael G. Loeks]

They are not the same.  Inches of Mercury =  0.4912 PSI. A vacuum gauge only 
goes to 30"Hg because that is for all practical purposes the maximum vacuum 
at normal atmospheric pressure. Once the vacuum approaches 30"Hg a 
mechanical gauge isn't adequate but that is a whole other can of worms. 
HTH,
Mike Loeks


> > The boost side is marked in psi, I seem to understand that
> > one.  The vacuum side is measured in "in of Hg".  So is 20 "in
> > of Hg" the exact opposite of 20 psi, or are they completely
> > different scales?  In other words if I had the palm of my hand
> > in the flow of the haidryer under boost, would the back of my
> > hand feel the same rush of air whe under vacuum?
> >
> > Another oddity is that on the vacuum side my VDO gauge marks
> > 30 in of HG while the boost side only reaches 25 psi.