djl@fisher.UUCP (Dan Levin N6BZA ) (09/23/85)
On the topic of octane methods (this gets bounced around now and then,
seems like time again..):
One methed (the R(esearch) method) is to calculate the theoretical octane
rating of a fuel based on its components.
The other (the M(something) method) is to take a one cylinder engine, and
change the compression until it just barely knocks on your test fuel.
Then find the iso-octane and hexane(?) mix that just knocks in the same engine.
Since the octane rating is literally the percentage of iso-octane in the
equivilent octane/hexane mixture, this rather pragmatic test will reveal
the 'true' octane rating.
The R+M/2 you see on the pumps in some states means that the octane rating
was calculated based on the average of these two methods.
About mixing fuels:
I am told by people I trust that mixing leaded and unleaded fuels produces
a very interesting resulting octane rating. In particular, mixing leaded
regular (89 octane) in equal parts with unleaded regular (87 octane) will
result in a ~90 octane fuel. Of more interest to older car fans, mixing
leaded regular (89) with unleaded super (92) will give you at least
92 octane fuel with enough lead in it for your valves. Your milage may
vary based on the amount of alcohol in the unleaded gas.
I do not think that mixing leaded fuels of differing octane ratings
will do anything unexpected.
About mothballs: ( No flames from chemists on minor points please...)
Seems that gas is basically just a mixture of carbon chains (in essence at
least), the longer the average chain, the higher the effective octane
rating. Also seems that some mothballs (there seem to be two kinds, I do
no suggest getting the wrong one!) are 100% (in fact lab grade, although
not USP) naphthalene(sp?). Seems that naphthalene is a very long carbon
chain, and that it dissolves fairly quickly ( ~ten minutes or less) in
gas. I have had several chemically oriented Ivy League types consider
possible bad side effects, and they all admit that naphthalene should
burn completely at combustion chamber temps, and that it is very, very
stable stuff, sufficiently so that it will not react and form any nasty
compounds in my engine.
This all boils down to saying that adding 3 real moth balls per gallon
to my tank will make my car run on leaded regular (89), which means that
it is bringing the octane up to ~92 or so.
So enough on fuels for now. For those of you who are wondering, I drive
a '65 Mustang fastback with a 10.5:1 c.r. 289, and it doesn't like
87 octane unleaded fuel too much :-)
--
***dan
{allegra,astrovax,princeton,twg}!fisher!djl
The misplaced (You call *that* a ski slope??) Californiancarlson@ssc-vax.UUCP (Lee R Carlson) (09/26/85)
> One methed (the R(esearch) method) is to calculate the theoretical octane > rating of a fuel based on its components. > I believe that the "R" (for Research (note caps)) is for General Motors Research Laboratories, inventors of the method. -- -- Lee Carlson -- Boeing Errorspace, Seattle ...{uw-beaver|fluke}!ssc-vax!carlson
mpc@rayssd.UUCP (Manny P. Costa) (09/26/85)
=== REFERENCED ARTICLE =================================== > About mothballs: ( No flames from chemists on minor points please...) > > Seems that gas is basically just a mixture of carbon chains (in essence at > least), the longer the average chain, the higher the effective octane > rating. Also seems that some mothballs (there seem to be two kinds, I do > no suggest getting the wrong one!) are 100% (in fact lab grade, although > not USP) naphthalene(sp?). Seems that naphthalene is a very long carbon > chain, and that it dissolves fairly quickly ( ~ten minutes or less) in > gas. I have had several chemically oriented Ivy League types consider > possible bad side effects, and they all admit that naphthalene should > burn completely at combustion chamber temps, and that it is very, very > stable stuff, sufficiently so that it will not react and form any nasty > compounds in my engine. > > This all boils down to saying that adding 3 real moth balls per gallon > to my tank will make my car run on leaded regular (89), which means that > it is bringing the octane up to ~92 or so. ========================================================== I'll be honest and admit right up front that I have never personally tried to do the following, but several "motor heads" that I knew in high school swore that this was true: If you really hate someone and want to ruin the engine of their car, pour a box of mothballs into his gas tank. They said it worked better than pouring sugar into the gas tank. Okay all you "motor heads"/chemists, is this true, or will you merely boost this guy's engine performance? Thanks, Manny Costa Raytheon Submarine Signal Division PO Box 360 Portsmouth, RI 02871
larry@kitty.UUCP (Larry Lippman) (10/14/85)
> > About mothballs: ( No flames from chemists on minor points please...) > > > > Seems that gas is basically just a mixture of carbon chains (in essence at > > least), the longer the average chain, the higher the effective octane > > rating. Also seems that some mothballs (there seem to be two kinds, I do > > no suggest getting the wrong one!) are 100% (in fact lab grade, although > > not USP) naphthalene(sp?). Seems that naphthalene is a very long carbon > > chain, and that it dissolves fairly quickly ( ~ten minutes or less) in > > gas. I have had several chemically oriented Ivy League types consider > > possible bad side effects, and they all admit that naphthalene should > > burn completely at combustion chamber temps, and that it is very, very > > stable stuff, sufficiently so that it will not react and form any nasty > > compounds in my engine. > > > > This all boils down to saying that adding 3 real moth balls per gallon > > to my tank will make my car run on leaded regular (89), which means that > > it is bringing the octane up to ~92 or so. > > I'll be honest and admit right up front that I have never personally tried > to do the following, but several "motor heads" that I knew in high school > swore that this was true: > > If you really hate someone and want to ruin the engine > of their car, pour a box of mothballs into his gas tank. > They said it worked better than pouring sugar into the > gas tank. > > Okay all you "motor heads"/chemists, is this true, or will you merely boost > this guy's engine performance? Enough, already! Napthalene is neither a long-chain hydrocarbon (it is an aromatic hydrocarbon consisting of two benzene rings), nor is it useful as a motor fuel additive. The combustion properties of napthalene are quite different from that of gasoline, and if anything, napthalene will not undergo complete combustion and will likely leave carbon deposits resulting in engine damage. I have a theory as to how this napthalene rumor got started: There is a chemical called ``decahydronapthalene'' which is also called ``napthalane'' (note different spelling!). This material exists as a liquid and has chemical properties which are quite DIFFERENT from that of napthalene. This material IS USED as a motor fuel additive; I believe it's primary function is that of a lubricant. I would suggest that no one seriously consider adding mothballs to their gasoline... === Larry Lippman @ Recognition Research Corp., Clarence, New York === === UUCP {decvax,dual,rocksanne,rocksvax,watmath}!sunybcs!kitty!larry === === VOICE 716/741-9185 {rice,shell}!baylor!/ === === FAX 716/741-9635 {AT&T 3510D} syr!buf!/ === === TELEX 69-71461 ansbak: ELGECOMCLR {via WUI} ihnp4!/ === === === === "Have you hugged your cat today?" ===