At 02:44 PM 5/23/97 -0400, you wrote:
>Rob Agnew wrote:
>>
>> Not true. There is 30% less energy in a litre of propane than in a litre
>> of gasoline (therefore fuel economy falls - miles per gallon). However, by
>> advancing the timing (higher octane), you increase you're fuel economy a
bit.
>
>
>Correction:
???? Correction ???? you've only snipped part of what I said Tom, this and
my previous note agree. :)
>
>Quoted from U.S. Department of Energy, Alternative Fuels Data Center at:
>
>http://www.afdc.doe.gov/misc/cngfacts/cn12.html
>
>Start Quote:
>
>Vehicle Performance
>
>Converted vehicles drive very much the same as gasoline vehicles. The
>most significant difference a driver may notice is a slight power loss.
>
>Because all engine parameters are not fully optimized in converted
>vehicles, full emissions, power output and fuel economy benefits are not
>achievable. For example, use of CNG in an engine may result in a 10-15%
>reduction in power. Propane use may result in loss of power up to 7%.
>
>The power loss is primarily related to the displacement of intake air by
>the fuel vapor. Since gasoline is metered as a liquid, there is very
>little
>displacement of the intake air. Excessive loss of power, however, may
>indicate improper installation or tuning of the conversion system. Just
>as
>with conventional gasoline vehicles, power and performance can be
>optimized through engine adjustments of the air/fuel mixture, ignition
>timing
>and compression ratio.
>
>End Quote
>
>> Depending upon your application, fuel economy may stay the same or drop
off.
>
>I have seen an improvement in fuel economy with a slight decrease in
>performance in my '85 pickup. The engine is stock, with only the
>carburator replaced.
>
>The increase of fuel economy is usually due to an inefficient carburator
>being replaced with a more efficient mixer.
>
>IMHO.
>
>Tom McCabe
>'96 Dakota CC, 2wd, 5.2L, Auto, 3.55SG, Gibson Cat Back Exhaust
>'85 D250 P/U, 2wd, 5.2L, Auto, On Propane (Awaiting 340 transplant)
>
>
>
Rob Agnew
ragnew@islandnet.com
Victoria, B.C.
Canada
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