water injection questions

[Robert E. Yorke]

Donald:  You are correct; I was referring to the end consequence of octane
rating procedure and rationale.  The resistance to pre-ignition/detonation
(They're NOT the same) is closely associated with burn rate, which in turn
is associated with combustion (Test) chamber configuration, which affects
flame front propagation as well as a host of other factors (ad nauseum). The
real world  use of octane rating for fuels is as a gauge for determining
burn time to allow for successful advance curve determinations.  Cutting
through all this crap I've tried to throw up, I'm trying to say that even
though octane is a measure of "knock" resistance, it as a consequence, is a
measure of burn rate! 

At 09:38 AM 7/22/96 -0400, you wrote:
>> 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
>
>
Riverside, CA
2 '88 GTs!