water injection questions

[Donald Whisnant]

> From: Robert Yorke <yorker at deltanet.com>
> Date: Sun, 21 Jul 1996 20:38:47 -0700 (PDT)
> Subject: Re: water injection questions
> 
> <snip>
>
> A lot of people mix Methanol (50/50) with the water.  Water alone will act
> to slow the combustion process; equivalent to raising the Octane rating (All
> Octane rating is, is a gauge of how fast a particular gasoline fuel burns in
> a combustion chamber).  The ignition timing can then be CAREFULLY advanced
> to take advantage of this.  With Methanol, you have a more pronounced effect
> (The equivalent Octane rating for Methanol is 105).
> 
> <snip>


I have a question about octanes (and this may show my ignorance regarding
octane ratings, but) --  I've always been told and under the impression
that the octane ratings on gasoline (not sure how it compares with
Methanol) were not ratings as to how slow the fuel burned, but a rating of
its resistance to pre-mature burn -- i.e. ignition from combustion chamber
heat while being compressed...  But here, you are saying the octane
determines the rate it burns ...  If that were the case, wouldn't increasing
the octane w/ignition advance give exactly the same results as lowering
the octane w/ignition retard? -- I guess the point is to have a repeatible
mixture that is consistant (i.e. not having pre-mature ignition on some
cycles and delayed ignition on others)...

Donald Whisnant
dewhisna at ix.netcom.com