On May 7, 7:05=A0pm, Dyno <d...@[EMAIL PROTECTED]
> wrote:
> jim wrote:
>
> > Dyno wrote:
>
> >> I was all set to fire off a followup, but you beat me to it, almost
> >> point by point. A lot of the nonsense that gets posted could easily
be
> >> avoided is some posters would simple go buy an engine text book and
> >> simply browse through it.
>
> > Here is what you said on how octane affects fuel economy.
>
> >> When I think of fuel economy, I think of light-load operation;
cruising=
> >> down the highway or driving around town. On a time-weighted basis,
unde=
r
> >> these conditions engine loads (BMEP levels) are relatively low. It is
> >> also at these conditions that the octane requirement is also low.
>
> > =A0 =A0 If you read your engine textbook you will find that the RON
rati=
ng is
> > made under light load conditions just as you describe. You are correct
t=
o
>
> No it is not. Apparently you do not know under what conditions the
> octane ratings are obtained. Contrary to what you said both the Motor
> method and Research method are obtained at WOT. Do I really need to list
> the specifics of methods used?
>
> > The fuels properties to knock under light loads is exactly what the
> > RON test determines. Engines do knock under light loads even if you
thin=
k
> > they don't ( and even if you can't hear it) and that does impact on
gas
> > mileage. =A0
>
> Interesting assertion here. Please provide a source for this. In my 30
> years of engine testing this is a new "fact" for me. And in much of my
> testing, I have acquired and viewed the in-cylinder pressure data and
> have not seen this.
>
>
>
> > =A0 =A0The problem is you don't have any idea what the RON rating is
for=
the
> > fuel in your gas tank and it can vary quite a lot for any given posted
> > pump octane rating. But in spite of the fact that you have no idea
what
> > the octane is in your gas tank under those conditions that could
> > potentially be giving you better mileage, you are positive it has no
> > affect on mileage cause you read something in a book.
>
> > -jim
>
> This is absurd. You dismiss textbook information that has been verified
> over and over just because it doesn't fit your pet theory; a theory that
> you have yet to provide any refereed literature on. Have even read any
> of the books? Here's a good one: Heywood's "Internal Combustion Engine
> Fundamentals". This book not only explains the major phenomena but also
> provides literally thousands of technical journal articles as
> references. Can you do the same?
Heh. that was actually a textbook for one of my college courses.
Thanks for the flashback.
I think I still have it, as it was a third or fourth year class so I
wasn't able to sell it to buy the next year's books...
nate
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