Does it make sense? Re: <VV> E-85 LONG

[FrankCB at aol.com]

In a message dated 8/21/05 8:06:38 AM Eastern Daylight Time, PIROCZ at aol.com 
writes:

> Has anyone looked into running the E-85 fuel in there cars. It's rated at 
> 105 
> octane and is selling for aroung $2 a gallon.
> 

        Well, Brazil tried running most of their cars on ethanol (grain 
alcohol) a few years ago, but the idea became so popular that they had shortages of 
alcohol throughout the country.  So the sales of alcohol powered cars 
plummeted since people felt that their ability to refuel might completely disappear.  
Now, however, with the skyrocketing price of crude oil, Brazil is starting to 
again market cars that can burn ethanol.  But these newer cars are different 
in that they can also (or instead) burn gasoline so the owners can buy 
whichever fuel is cheaper or available at any given moment.
       In line with this, Saab has created what they call a "BioPower" engine 
in a car already being sold in Sweden.  According to the July 2005 issue of 
Popular Science magazine, this car "could hit these shores next year".  It has 
a sensing device that analyzes the fuel flowing into the engine (maybe by 
measuring refractive index?) and adjusts the computer control to compensate 
whether the fuel is 100% gasoline or 85% ethanol (with 15% gasoline) [called E-85] 
or ANYTHING IN BETWEEN those 2 extremes.  So on a trip you could start out with 
E-85 and refill with pure gasoline at the first stop and then E-85 for the 
next refueling.  You might end up with E-23 in your tank after the first stop 
and E-68 after the second and the computer would adjust the A/F ratio for the 
injectors as well as the ignition timing.
       Popular Science states that the octane rating of E-85 is about 110, 
considerably higher than even premium gasoline.  But you can't readily change 
the compression ratio of the engine each time you fill up your tank with a 
different octane fuel.  The Bio Power Saab engineers have developed an ingenious 
solution by varying the boost level of the turbocharged engine based on the 
composition of the fuel.  With 100% gasoline the boost level is about 6 psi 
producing 148 hp; with E-85 the boost level is increased to about 14 psi raising the 
power to 184 hp.
       Getting back to your question, the article states that E-85 has about 
75% of the energy of straight gasoline, so paying $2 for E-85 is equivalent to 
paying $2/75% = $2.67 per gallon for gasoline.  Therefore the price of E-85 
would have to be less than $2 OR the price of gasoline would have to be greater 
than $2.67 to even consider changing over to E-85.  However, this assumes 
running the same compression ratio for both cases.  If you increased the CR to 
take advantage of E-85 you would then improve the mpg as well as the power 
output.
       There are additional costs involved with converting an existing car to 
E-85.  Alcohol fuels are more corrosive than gasoline so the entire fuel 
system would have to be modified.  In addition, the stoichiometric ratio for E-85 
is about 10 to 1 A/F compared to 14.6 for straight gasoline, so carburetion or 
fuel injection control would have to change.  So at this time, it does not 
seem economical to convert engines from gasoline to E-85.  However, if the price 
of gasoline rises substantially OR the cost of ethanol can be reduced (our 
sugar costs us about 2X world price because of US government control) then it 
could make sense to BUY your next car with flexible fuel capability.
       Even if we have to subsidize alcohol fuel production, I for one would 
rather have my money go to Joe Corncob than to Mohammed Osama.  Besides, Joe 
Corncob is not likely to use my money to commit acts of terror against me and 
my countrymen.  But that discussion is getting us rather removed from fueling 
our Corvairs.
       Frank "verbose" Burkhard