Re: Surprising increase in truck MPG

jim <"sjedgingN0sp"@[EMAIL PROTECTED]
> wrote in news:1208618428_262@[EMAIL PROTECTED]
> 
> 
> Nate Nagel wrote:
> 
>> 
>> I find that hard to believe, but I suppose it might be possible with
>> closed-loop engine controls, a high-compression engine, and a knock
>> sensor/spark retard *if* you were previously running on low-octane
>> Mexican fuel.
> 
> 
> Wake up! What you came to know as "low-octane cheap mexican fuel" 40
> years ago was better fuel than what most cars in America have in their
> tanks today. And yes that poor grade of fuel does  have a lot to do
> with why ethanol improves mileage - that is correct. 
> 
> 
> 
>>  Not all vehicles have closed loop, however (basically any
>> engine without an oxygen sensor has no means of feedback mixture
>> control) and I just don't see any mechanism by which a less energy
>> dense could actually produce a lower BSFC at the same power output.
> 
> The cars tested were modern fleet cars. Double blind studies so that
> they weren't influenced by driver's prejudices.
> 
> 
> 
> 
>> 
>> > It is also well known
>> > that the addition of alcohol to gasoline results in higher octane
>> > and in more complete combustion of the fuel than gasoline alone.
>> > Which explains why energy content calculations mean nothing.
>> 
>> Higher octane doesn't mean squat unless you also mill the heads or
>> otherwise increase the compression ratio.
> 
> Or unless the fuel is really low octane without it. Most gasohol is
> only 87 octane. the fuel would be like 84 octane without it. 


  here in the midwest most ethanol gas is 89 octane. 87 octane ethanol 
is bastardized poor gas brought up to 87 octane with the ethanol octane 
increase. I have found huge differences between these two blends. the 89 
has always worked great in most stuff. the 87 can be terrible stuff and 
result in really poor milage in anything with any real compression.   KB


> 
> 
>> 
>> >       However, The OP re****ts he was getting 10 mpg and it has
>> >       recently 
>> > increased to about 12 mpg - it is doubtful ethanol has much to do
>> > with his poor gas mileage. But if it does have anything to do with
>> > it - it is more likely the increase in mileage was due to gasohol
>> > not the other way around.
>> 
>> I'm curious how you come to this conclusion...\
> 
> Because studies have shown that adding 10% ethanol does improve gas
> mileage in most modern vehicles - therefor for any one particular
> vehicle it is more likely it will increase mileage than decrease it.
> However, it is unlikely you will be able to find any reliable testing
> has been done on a fleet of 50 yr. old Studebakers.
> 
> -jim
> 
> 
> 
> 
>> 
>> nate
>> 
>> --
>> replace "roosters" with "cox" to reply.
>> http://members.cox.net/njnagel
> 
> 
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