As Hugh mentioned, this is a thread that could go on
forever, but as a student of engineering (and I'm sure
Dimitrios will back me up here) I wish to correct a
possible misconsception.
> current engine set up. It seems to me there is no
> such thing as premium
> fuel. It is all the same stuff, only the plus and
> the supreme have
> additional additives. The latent power is exactly
> the same. the additives
> serve to provide a higher resistance to knocking or
> pinging and that's it.
> I have never heard of detergent in gasoline, but
This is not true. Iso-octane is one of two (basic)
hydrocarbons that comprise gasoline. In its purest
form, gasoline is x parts iso-octane (which is by
definition 100 octane) and 1-x parts n-heptane (which
by definition is 0 octane). The mixture gives the
overall octane rating. Octane is actually calculated
empiracly using a standard engine with a variable
compression ratio, so that the engine can be adjusted
to run without pinging for any octane fuel.
Octanes above 100 are possible with different
substances such as methyl tert-butyl ether (MTBE),
among others.
The higher the octane, the greater the power that is
available, but, if the engine is not tuned for it, it
will be unable to utilize this extra power. Advancing
the timing can take advantage of some of this extra
power by "fooling" the gasoline into thinking you have
increased the compression ratio. But, it only will
work up to a point.
As for detergents and additives, I have heard that all
grades of gasoline from a given manufacturer have the
same basic additives and detergents, and really there
are only 2 or three producers of gasoline anyway..just
lots of different station names!
I run 93 octane in my Imperial, with 14 degrees of
initial advance, very little vacuum advance, and an
average amount of mechanical advance. I also put in a
bit of lead substitute from time to time, prolly more
for my peace of mind than anything else. But hey, its
cheap. ;)
=====
--Mike Pittinaro
Christmas is over now
So I'm changing my haiku
Thank you, David Brown
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