<VV> Re: Alternate fuels-corvair conversion

[JVHRoberts at aol.com]

Frank, you need to correct for density. Gasoline is 6.6 pounds per gallon.  
Propane is only  3.5 pounds per gallon. Meaning, on a weight basis, you  only 
get about half as much fuel per gallon with propane, and about half as much  
energy per gallon as well. 
Furthermore, nearly all propane comes from petroleum. Natural gas comes  from 
gas wells. 
 
In a message dated 8/19/2005 7:51:25 P.M. Eastern Standard Time,  
FrankCB at aol.com writes:

You really have to look at cost per 1000 BTUs to get a  realistic 
basis for comparison of 2 different fuels.  If you can get  propane at $1.59 
per 
GALLON then it costs about 1.75 cents per 1000  BTU.  Gasoline at $2.50 per 
gallon costs about 2.1 cents per 1000  BTU.  So based on heating value, the 
cost of 
gasoline would have to  be $2.08 per gallon to equal the $1.59 per gallon you 
cite for  propane.  But would this justify the cost of conversion of an 
engine's  
fueling system from gasoline to propane?
If  you drove 15,000 miles a year and got 25 miles per gallon on 
gasoline at  $2.50 per gallon the cost for a year's worth of gasoline would 
be $1500.  
Using propane would give you only about 19 mpg and, at $1.59 per gallon,  the 
cost would then be about $1260 for the year's fuel.  That would  save you 
about $240 per year.  How many years would you have to drive  to justify the 
cost 
of conversion?  
Incidentally, the (R+M)/2 octane rating of propane is 108 so you could  
substantially raise the compression ratio of your engine to improve the  mpg 
figure if you planned to convert to propane.  This would further  increase 
the 
yearly saving.
Unfortunately,  most propane is produced from natural gas which has 
been increasing in  price the past few years just as petroleum has.  So who 
is to 
say how  long the price of propane will remain below that of gasoline on an 
energy  content (BTU) basis.
Frank  Burkhard