DIY_EFI Digest V4 #518

[Greg Hermann]

>Date: Fri, 10 Sep 1999 15:24:29 -0700
>From: "John Dammeyer" <johnd at autoartisans.com>
>Subject: Vapour Pressure
>
>Hi All,
>
>Does anyone have the formulae for Vapor Pressure?  If I assume RH is 75%
>and can
>measure the Air Temperature inside the intake manifold what is the calculation
>for vp?
>
>Thanks,
>
>John

You need some combination of psychrometric charts or GOOD steam tables. A
good steam table will include a section giving the equations upon which the
values stated in the tables are based.

If RH is 75%, the VP will be 75% of the VP (partial pressure of H2O vapor)
at saturated conditions for that temp.

Greg