I added premium unleaded to my gas can (plus oil) this time around for my chainsaw. My chainsaw seemed to run a little hotter, which was helpful, but I wonder if this is not the best thing for the machine. Any thoughts? Thanks.
The small engine shop that services my equipment tells me that the best
thing to use in those items is the pre-mixed fuel sold in the quart
cans. The reason? It's premium fuel, with stabilizers and NO ALCOHOL.
The last is the biggie. Over time the ethanol added to the fuel will
wreak havoc with your 2-cycle engine. So, you using premium is a good
thing and you can make it better if your state allows for mixtures
without ethanol. I know that Wisconsin does, but Illinois doesn't.
On Sun, 27 Dec 2015 12:48:57 -0600, Unquestionably Confused wrote:
Washington allows it. I've found that my ancient 500cc motorcycle gets
50mpg with ethanol, 60 without. And the ethanol does bad things to tank
liners in old bikes.
BTW, eliminating 10% ethanol increases my bikes mileage by 20%. Tell me
how I'm lowering pollution with ethanol :-).
This < Canada Natural Resources > website
shows some fuel economy data -
- example - 2013 Dodge 1500 8 cyl. auto pickup -
on regular gas 14.6 litres per 100 km
on E85 ethanol 21.8 litres per 100 km
"regular gas" might be some ethanol content ?
in your area. ? dunno.
A difference of ~ 7 litres per 100 kM !
for using the highly subsidized corn alcohol .. ?
Geeeze ... am I missing something ?
email@example.com wrote in news:hbp08bh7j6h18fpb5gv4npmgae7ckg1hfq@
Regular gas is usually 10% or less ethanol. Exactly how
much depends on whatever other additives they're using,
and the octane rating they want. The reason for putting
ethanol in regular gas is that it's a very effective
octane booster, and unlike other octane boosters such
as MBTE it's more-or-less non toxic.
That sounds about right for E85. Corn alcohol makes
a very poor fuel. With current technology, the only
economically viable (and enviromentally sound) way
to make alcohol fuel is to start with sugar.
On Sun, 27 Dec 2015 23:59:20 -0000 (UTC), John McCoy
The reason ethanol is added to fuel in North America is NOT for octane
improvement. It is added as an "oxygenator"
It is supposed to reduce the carbon monaxide and particulate emissions
of the vehicle.
You are confusing two different things here, both of
which ethanol happens to be good for.
One is octane rating. Raw gas (no additives) has an octane
rating (*) of around 70, so something has to be added to
raise it to a useful level. Historically that was tetra
ethyl lead, which of course is now banned. Ethanol has an
octane rating of around 110. So adding ethanol to gas is
a very effective way to raise the octane rating.
The second is oxygenation. In ideal conditions there is
enough oxygen in the air entering the engine to completely
burn the fuel. Ideal conditions don't always occur, so
a fuel additive that contains oxygen can help get to
complete combustion. Ethanol contains oxygen, so it is
effective as an oxygenator.
Until 2007 there was a Federal requirement (in the US) to
include oxygenators in fuel. That requirement no longer
exists. The reason ethanol is added to gasoline now is
for it's value as an octane booster.
(* octane rating is a confusing thing, because there are
several common ways of testing it, which give different
numbers. In North America the AKI (or R+M/2) method is
used, which is what the numbers above are based on).
On Mon, 28 Dec 2015 14:48:46 -0000 (UTC), John McCoy
Hydrocracked/catalytic cracked first run gasoline has an octane of up
to 90 with no additives.
There is no such thing as an "octane" rating of over 100. Over 100 it
is an "aki" or antiknock index..
Then why is ethanol added to regular gas at 10% and not added to
premium (in very many cases)???
The ethanol is added to regular gas because that is the easiest way to
sell the volume of ethanol mandated. The total amount of gasoline sold
in an area needs to contain, say, 9% ethanol (maximum limit is 10%)
and 99% of gas sold is regular (or a mix containing regular) so they
do not HAVE to put it in the premium gas.
Also, the ethanol is not added at the refinery (at least in many
cases) it is added to the tanker at the depot - so the regular gas at
the depot has to be 97 octane without ethanol.
I don't "buy" the ethanol as octane booster arguement - at least here
in Ontario. Does it increase Octane? Sure. Is octane the reason it is
added? No. It is added because it is mandated. It is mandated because
it is an oxygenator. The octane boost is just a bonus. (which helps
mitigate thedilution of the fuel energy caused by the dilution of the
fuel with low energy ethanol in the eye of those who don't understand
octane requirements and energy content and the fact they are not
connected in any way)
firstname.lastname@example.org wrote in news:jas28blrb27snvfj6g8q5ujft8c9ugnf9c@
Antiknock Index and Octane Rating are the same thing. You're
trying to sound intelligent there, but you're shooting
yourself in the foot...
It usually is added to premium in the US. I don't know
why Canada is different, but I suspect it's due to tax
In the US, ethanol is used because:
a) it's an effective octane booster
b) it's cheap compared to the alternatives
c) the energy act of 2007 provides Federal incentives
d) it does not have the legal liabilities of MBTE
Incidently, ethanol isn't "added to gas at 10%". The amount
used varies, from 5% to 10%, depending on the octane rating
On Tue, 29 Dec 2015 19:28:08 -0000 (UTC), John McCoy
t octane only goes to 100 because you can NOT have
aoiso-octane/heptane mixture more than 100% iso-octane.Check your
facts. Anything over 100 is AKI
It's because if you have to sell a certain amount of ethanol, put it
where you will sell it fastest.
Mabee in the US of A, but not here in Canada. Ethanol is used as an
oxygenator up here. The extra octane is just a "bonus" if you can call
anything that reduces the energy output of a fuel a "bonus"
Up here it is "may contain up to 10% ethanol by volume"
On 12/29/2015 3:10 PM, email@example.com wrote:
Exactly! Typically alcohol reduces gas mileage. My Tundra which was
designed to run or regular gets better gas mileage with premium from the
same gasoline station. Now that the price difference out weighs the gas
mileage benefits I have cut back from using premium and over all my gas
mileage has suffered.
Now there are other reasons that I get better gas mileage from premium
but most likely the lack of alcohol is just one of them.
firstname.lastname@example.org wrote in news:sft58b93crkcqiru2mqeh5snjegtsqv74s@
You are confused here.
There are several methods of calculating octane rating,
the two most common being the "research method" and the
"motor method". They work the same way, you run the
fuel being tested in a special motor which has a
variable compression ratio, and compare the point
where preignition starts to the point where it starts
with a particular isomer of heptane (defined as zero
octane rating) and a particular isomer of octane
(defined as 100 octane rating). It's entirely possible
for a fuel to accomdate a higher compression ratio
than the octane standard, in which case it's octane
rating is proportionally greater than 100 (conceptually
it's also possible for a fuel to not reach the compression
ratio of the heptane standard, in which case it would
have an octane rating less than zero).
Now, in the UK and Europe, they use the research method
exclusively. Their octane ratings are always RON (and
they have no such thing as an antiknock index). In
North America they take the average of the research
method and the motor method, and call the result the
"pump octane rating". You'll see this on gas pumps:
(R + M)/2. (there are exceptions in the US - racing
fuel is often specified by RON, and av-gas is specified
For simplicity, rather than say "the average of the
research method and the motor method", (R + M)/2 has
also come to be known as the antiknock index, or AKI.
It's just another term for octane rating.
On Wed, 30 Dec 2015 21:56:29 -0000 (UTC), John McCoy
I understand how octane is determined - and since there is no such
thing as more than 100% iso-octane to put in the test mix, 100 octane
is as high, technically, as an "octane rating" can go. From 100 on up
it is "technically" an Anti Knock Index. AKI can also be used below
100.RM/2 is used for automotive motor fuel in North America - but not
for Aviation Gas.
I remember this being taght by the petroleum engineers from Texaco,
Imperial and Shell when I worked for garages that sold those 3 brands
of fuel "way back in the day" between 1968 and 1983. They said
although often refered to as the "octane rating" anything over 100 is
technically the AntiKnock Index, which in Noth America is generally
referred to as "road octane" or "R+M/2" or "pump octane" while
elsewhere in the world it is generally ROM - straight "research
Octane sensitivity has to do with the difference between research and
Motor Octane is also sometimes (mistakenly) referred to as "rich"
octane and is the measure of anti-knock qualities under sustained high
load, (accelleration at low RPM) while research octane is sometimes
referred to as "lean" octane - the measure of antiknock qualities
under typical mild driving.(high rpm low load)
They call it sensitivity because it indicates hpw sensitive the fuel
is to varying conditions of tempwrature and load.. Sensitivity of most
automotive gasoline in North America is generally about 10 points.
In europe recently the sensitivity has been higher, (20 points and
more), meaning some fuels (under 105RON)do not meet the required 85?
minimum MON for European regulations.
Lean and Rich octane ratings are used to rate aviation fuel.. They are
similar to the RON and MON , in that rich mixtures are used under high
power settings, and lean under lower power settings. The "sensitivity"
of Avgas is generally closer to 30 points (100-130 for instance for
100LL regular avgas) Lean rating in AvGas is always lower than rich
rating, just as MON is always lower than RON in Mogas. It is a
combination of actual differences in the knock resistance of the fuel
and differences in the measurement protocol that contribute to tne
higher "sensitivity" of AvGas.
The AvGas "lean octane"number is not necessarilly the same as the RON
number would be for the same fuel, but it is close.
Thanks for reminding me of that. After being told of the pre-mix and
using it. I went looking for premium here without success. Found that
very site and, unfortunately, those are all downstate pumps subject to
different regulations which are imposed on us "lucky" devils residing in
NE Illinois. I can, however, head north about 15 miles and get all the
premium, ETOH free gas I want.
On Sun, 27 Dec 2015 12:48:57 -0600, Unquestionably Confused
I use alcohol-free gas for my small machines (yard tractor on down).
It's readily available, though expensive, here in Georgia. It doesn't
surprise me that it's illegal in IL. Nothing IL does surprises me.
high octane fuel does not cause an engine to run hotter, contrary to
common belief. However, running gasahol MAY cause the engine to run
cooler due to reduced energy content. The chances of damage due to
running "hooch" FAR outway any possibility of damage from running
If the octane is too low (and adding oil lowers the octane) an engine
will detonate, and detonation transfers more heat to the piston, cyl,
and head by disrupting the "boundary layers" causing the engine to
In aircraft, the first sign of incipient detonation is a simultanious
increase in head temperature and drop in EGT (Exhaust Gas
When that happens you have seconds to pull back on the throttle to
avoid engine damage and possible engine failure. Doesn't matter if
it's a 2 stroke ultralight or a 4 stroke Lycosaurus
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