fuel is required to travel one mile than non-alcohol gasoline. But before
you start screaming, keep in mind that the 33-percent reduction in BTUs
is for only 10 percent of the total fuel content, so the penalty is only 3.3
percent. For E-15, the penalty is 5 percent, and with E-85 it’s up to 30
percent. The overall BTU value of E-10 is 110,400 BTU per gallon.
On a side note that has nothing to do with ethanol, your engine is
not 100 percent efficient in converting all the fuel into power at the
drivetrain. So how close to 100 percent are we? Well, your 13-mpg 289
Hi-Po is actually only approximately 13 percent efficient in converting
energy (gasoline) into force (moving your Mustang down the road). A
100-percent efficient engine in your Mustang would allow you to travel
approximately 100 miles on a gallon of fuel. Sounds good, but I’d rather
burn a bit more gas in my Hi-Po and have fun doing it.
INCREASED OCTANE RATING
Most assume the octane rating (87-93) is a correlation of the fuel
value of gasoline, or how much energy (BTUs) is contained in a gallon.
Not true. The octane rating or number is a measurement term used to
identify the ability of a fuel to resist spontaneous combustion. The lower
the octane rating, the greater the tendency is to prematurely ignite due to
heat and compression in the cylinder housing, and cause engine knock.
This knock is most noticeable when the engine is under load while climbing
a steep hill or accelerating while passing another car.
The octane rating of pure ethanol is 97, or 11 percent higher than the
87 octane you’re filling your tank with. So, the more ethanol you have in
your fuel, the less likely you are to experience engine knock.
DECREASED BURN RATE
Burn rate is a measure of the time required to fully combust the fuel
in the combustion chamber. At higher rpm, there’s less time available for
the fuel to burn. If the combustion is complete by the time the crankshaft
reaches 20 degrees after top dead center, optimum horsepower and fuel
efficiency are achieved. Pure gasoline has a burn rate — measured in
milliseconds — that is only 2 percent faster than E-10, and 3 percent
more rapid than E-15. That’s not enough to make a difference, even
at 3,000 rpm. Not even your wired 347 could sense the variation in
burn rate.
QUARTER-MILE PERFORMANCE:
LABORATORY
While the BTU value of E-10 is less than pure gasoline, laboratory
tests* on a four-stroke engine indicate no true difference in torque
82 FOXMustangMagazine.com
generated between the two fuels. Therefore, your time in the quartermile should be the same, no matter which fuel you choose. That applies
to peak horsepower (hp) as well — no change. Why is that? One theory
suggests that the improved octane rating offsets the lower fuel (BTU)
value. The same goes for older engines — no change.
* Source: the International Journal of Engineering Science and Technology,
Volume 2, 2010
QUARTER-MILE PERFORMANCE:
ON THE TRACK
I quizzed a number of long-time participants at the recent Mid America
Ford Team Shelby drag racing event in Tulsa, and they all claimed there
is no difference in engine performance between the non-ethanol fuel and
E-10 fuel, at least not that they could detect. Again, worst case is you’ll
see a 3-percent drop in horsepower with E-10.
If that’s true, your 5.0 that was generating 225 hp on Esso fuel back
in the ’80s will today only do 218 hp on E-10. In the quarter-mile, your
14.80 seconds elapsed time on 100 percent gasoline will increase to a
15.24 with E-10. For E-15, the numbers will drop to 214 hp and 15.54
seconds. This all assumes that you have not increased the amount of fuel
you can burn in your engine during that 14.80-second sprint.
HARMFUL TO YOUR ENGINE
Bill Woerner of Arthur Gould Rebuilders has spent the past nine
years repairing fuel pumps that had previously been reworked with new
old stock (N.O.S.) diaphragms and gaskets. It seems that the 20-yearold N.O.S. rubber products don’t last long in E-10 service — about three
months, according to Bill. He and the small engine repair shop next to
his business both have seen significant corrosion on aluminum parts in
contact with the ethanol. It’s easy to spot: a white layer of corrosion on
the surface of the aluminum. And they didn’t see any corrosion prior to
ethanol being included with the gas.
You can find corrosion test results on the Internet that either back up
Bill’s claim or deny it. Is it dependent on the quality of the ethanol being
added? Who knows? But, everyone agrees that E-85 (85 percent ethanol,
15 percent gasoline), also referred to as flex fuel, is known to be corrosive
to aluminum.
There are many web pages touting E-10 to be harmful to rubber
materials produced today, but I couldn’t find any technical report that
backs up that statement. In fact, one O-ring supplier stated in his catalog
that nitrile (most commonly used rubber in fuel lines), buna-n, butyl,
and natural rubber all hold up extremely well to ethanol.
Other negative side effects that are being blamed on E-10 include