Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (August 2002, week 2)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Mon, 12 Aug 2002 15:51:47 -0500
Reply-To:     Larry Alofs <lalofs@ENTERACT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Larry Alofs <lalofs@ENTERACT.COM>
Subject:      psig?
Comments: To: TinkerMan <tinkerman007@YAHOO.COM>
Content-Type: text/plain; charset=us-ascii

TinkerMan wrote: > > > Thanks! > what's "psig" (sp?)? >

psig means pounds per square inch gauge. This is what most people mean when speaking of the pressure in tires, fuel lines, cooling systems, etc.

The other approach is "psia" meaning psi absolute, which would be about 14.7 psi more because it includes the air pressure around us all the time, at sea level on the average about 14.7 psi, 101 kPa, 1 bar or atm, or 760 mm mercury or torr. The computer in a fuel injection system wants to know the absolute pressure in the intake manifold, hence the term MAP sensor, manifold absolute pressure. Since you can't have less pressure than a complete vacuum, psia readings are never negative. Complete vacuum on the psig scale could be called -14.7, but since vacuum is usually measured in inches of mercury in automotive work, you see it as 30 in. on an AC gauge. Sorry, I'm a physics and chemistry teacher, just can't help myself...

Larry A.


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.