Great Falls tribune., 1921-06-19
Barney 0ldflde!d says:
WHAT IS YOUR GASOLINE
MILEAGE?

Il Half the automobile drivers OF the
country do not know whether their
.cars are economical or not. This is
mot a wild statement, but one which
III know to be true after making an
investigation among a representative
lot Of car owners. Gasoline economy
lin itself is, of course. advantageous.
saves the owner money, but it does
more than that. BY knowing the
fuel consumption of the car, one is
!, able to determine if all parts are func-
tioning properly. While it should be
the duty Of every driver to save money
in operating his car, the savings should
be done in q manner as will produce
the best results. The mere saving
Of fuel is little, because the difference
between the cost of running at 10
miles a gallon and at II or Is miles
a gallon, amounts to little at the end
of the year. The real reason for saw
Ing gasoline is to get more efficient
engine, better and smoother operat-
ing car, more speed and better all
around performance.
The average driver is unaware of
the consumption Of his car unless he
makes a test. but an occasional test
is Of little value, because of the vari-
atioIs in atmospheric conditions
roads, etc. Only recently it has been
shown by extensive Investigations
made by the best engineers in France
and England that lean mixtures are
better than rich mixtures, that is. it
is far better to run too lean than it
is to run too rich and in some in
stances it has been shown that even
mixtures which we call correct could
be made leaner with better results.
~ to Best Mixture.
We have been in the habit Of be
IA to 1, that is. IA parts Of air to
one of gasoline is about the limit. but
it has been found that engines give
better results and carbonize less with
mixtures as high as II to l. One i'm
portant point that has been empha
sized is that with the leaner mixtures
compression can be carried higher and
with normal compressions there is less
so-caled spark knocking.
The average driver. however. has
no means Of knowing just what his
mixture ratio is. and whether his car
is running on normal or abnormal
fuel consumption. Recently some
manufacturers have brought out dash
instruments enabling the driver to
know at glance just what the fuel
consumption is. One of these instru
ments is particularly good in that it
provides an economy factor which
multiplied BY the speedometere read
ing gives the miles a gallon at the
moment Of reading. Such instruments
should have universal application rri-
mariIy because they enable the owner
to check up on engine and chassis
efficiency.
When Something Is Wrong.
Most of the fuel assuring devices
show the gallons an hour consumed.
If the normal reading at % miles an
hour is three gallons an hour. and
after the car is overhauled the read
ing at that speed suddenly jumps to
four gallons an hour. it is easy to see
that there is something vitally wrong
in carbureter adjustment, valve set
ting. spark timing. or the fettins of
the engine or chassis parts. Without
knowing the fuel consumption a driv
er will continue using his car perhaps
for months before he discovers that
the timing is too late. or the valve
improperly set.
In the laboratories of the car man
ufacturers the fuel consumption fig
ures are used as accurate checks
against engine defects and there Is
no reason why the car owner should
not use similar check Take, tor
instance, the fuel consumed by under
inflated tires. 1t is surprising just
how much extra fuel is NEEDED TO nnll
a car along with tires 10 pounds be
low the necessary pressure. but the
owner will not discover this for some
time.
Underinfiation Cause Tread Wear.
During the time the tires have ruH
underinflated. the treads have worn
excessively and prehaps become partly
separated from the tire carcass. With
visible fuel consumption meter the
the driver can at once detect the in
crease in fuel consumption. and tEen
il is but matter Of running down the
exast cause.
In addition to checking this item
there are such matters rs the mix
ture ratio. errors made by the repair
shop in overhauling, etc. After car
is taken from the shop one can tell
at once of it is running at normal eff