Elmo P. Shagnasty wrote:
> In article >,
> wrote:
>
>
>>I get 46 overall, with 50+ at 70mph on the freeway.
>>2003 CVT. 50,000 miles.
>
>
> Wow.
>
> A buddy of mine, on a complete lark, went and bought a used Beetle
> diesel. 47K miles on it.
>
> His first full tank, in town, with the AC blowing hard, was 47mpg.
>
> I have yet to hear what his first highway drive did.

you know, this whole economy thing has really gotten me interested.
especially as you mention the diesel thing. on the one hand, diesel is
more thermodynamically efficient, so it's going to give better economy
anyway, but diesel fuel also doesn't offer the same degree of latitude
for, er, "variance" that gasoline does because it can become smoky, hard
to start, or worse, ruin injection equipment.

since that recent octane thread we had, i've been doing a little more
reading around on the subject of calorific content for gasoline, and
there really is a /huge/ reluctance by anyone [in the california market
at least] to quote figures for the energy content of their fuel. i find
this interesting because all other consumer goods are subject to
performance standards, not least of which is natural gas which is sold
by the therm, not the cubic foot. even gasoline is subject to rigorous
weights & measures inspection with state inspectors certifying pump
calibration at regular intervals. but, think about it, if you're
selling energy not by actual calories [therms in the case of natural
gas] but by volume [gallons], the relevance of the volume measurement is
somewhat questionable if the energy content is variable.

so, what do we have here?
http://api-ec.api.org/about/index.cf...02001000000000

and to repeat the most interesting paragraph in the whole page:
"Conventional gasolines also can contain oxygenates. They are added to
help meet octane number specifications and/or to extend the product volume."

extending product volume??? if using ethanol "volume extender", it has
about half the calorific content of gasoline meaning you need to burn
/more/ gas gallons to travel the same journey.

hopefully, the cost impact of this is obvious, but in case it's not,
consider this. imagine you're flying to tokyo from san francisco,
[about 1000 miles] against the jet-stream all the way. the pilot &
engineer carefully calculate their fuel requirement for the journey
based on their payload, known winds, distance, etc. imagine now that
they were buying fuel in gallons and that unknown to them, the energy
content of their fuel had been reduced by 10%. that could leave them
stranded in the ocean by nearly 100 miles. so, while i don't know this
for fact, you have to assume that either there is a base minimum energy
content for aviation fuel, /or/ that the energy content is known at the
time fuel calcs are done.

if there is a base energy content for aviation fuel, why not for cars?
it affects the amount of money i spend at the pump each week. if the
energy content is known, why not for cars? it affects the amount of
money i spend at the pump each week!!!

i'm now /definitely/ interested in this whole oxygenation thing. fwiu,
oxygenates are irrelevant for modern closed loop injection systems, so
could it be that the emphasis on oxygenates are actually the result of
the opportunity to use "volume extenders"???

>
> I'd think a Toyota Corolla could come close enough to that 46 overall
> number, and that without having any black magic software/hardware that
> no one but the dealer can fix.
>