carburetors that allow you to drive 1000+ miles to the gallon

cheapest gas in that area is a short drive away. The quik-trip on US19
in jonesboro (jump on I75 to Exit235, and follow US19/41 for about 2
miles. it was 2.03 iirc on friday

Its 2.12/gallon in central georgia, in the
griffin/barenesville/thomaston area. Cheaper still around the
Thomasville area, just in georgia on the florida border.

 

Car computers are very variable. Nowhere is this better illustrated,
than on Top gear a year or two ago, when the presenter drove an Audi
A8 from london to edinburgh and back on a single tank (thats around
400 miles, in a 4l V8 twin turbo diesel). Not only did the computer
say he was low on fuel too early, but that he'd completely run out
around milton keynes, an hour or so short.

low a speed as practical is not true. It comes from keeping at the
peak torque point. I used to do economy runs in my old volvo, its most
efficient speed was 58mph, because that was how the gearing worked out
to be the engines peak torque point, in the top gear. now, you could
actually cheat a bit and extend it, by going right behind a HGV (semi
for the americans) and holding steady at their limited speed 9usually
about 62-63mph). I think i managed to get about 55-60mpg from my volvo
in this way, thats in a 15yo car, with 4 passengers. Peak torque rpm
point is always the point where the engine works most efficiently.
thats how come its the peak torque point.

 

There's more to it than that, gearing and powerbands make a
difference. Fuel consumption's finite, it'll take a certain amount of
energy to maintain any speed. Reduced wind and rolling resistance
will reduce the energy needed, then it's just to how efficient the
engine is at that RPM in converting fuel to energy.

I used to get 34MPG at 70MPH with a 1962 Oldsmobile F-85 with a 215 V8
and a 4bbl carburetor.

Most cars today can't get that sort of mileage with fuel injection and
half the cylinders. So much for 40 years of engineering.

 

I think most would agree that California has the worst of these.

In February, 1998 in San Diego the average was $1.29 according to
http://www.fueltracker.com/whitepaper8-98/gasfinal.html.

Cheap fuel was a largely ignored economic factor through most of the
90's. I remember news stories about gasoline prices below a dollar in
GA.

I don't personally recall anything less than $1.09 locally, but we
only have three supplying refineries and two companies running those,
so competition's not keen.

 

Computers in carbureted cars and older injected cars have a lot of variables
(especially analog transducers to measure air or fuel flow), but the
computers in modern injected cars are very accurate - more accurate than
calculating on the basis of one or two fill-ups. The ECU knows exactly how
long it is opening the injectors (how many crystal-controlled clock cycles),
and exactly how often. The distance comes from the VSS in exactly the same
accuracy the car's odometer has, so the only variables are fuel pressure and
injector lag. Prius owners have reported errors ranging from 2% to a shade
over 5% optimistic. (Interesting that none report their displays being
pessimistic.) I don't recall any saying their display was 10% or more off
the actual unless they were comparing a single tank based on when the pump
clicked off.

Mike

 

Any fuel has a certain amount of stored potential energy. Burning that
fuel can release that much energy and no more. It takes a given amount
of energy to move a given amount of weight. A fancy carburetor can't
get more energy out of the fuel than it already contains, or reduce the
amount needed to move the car.

Usually you get a substantial amount less power out because of improper
combustion, and improved combustion can make for more efficient energy
production, but not THAT much more efficient.

CHAMP cars (the open-wheel racers used by CART) use a 2.65 liter V-8 (8
cylinders, but barely more displacement than my Accord) that get around
750hp. They burn straight methanol tho...