Saving Reality Check
jumping on the how to save gas bandwagon understandably.
Its on everyones mind. But that doesnt mean you
ought to believe everything you read.
theres the bogus:
tune-ups will save you gas
Most late model
cars (thats anything built over about the past ten years or
so) generally dont need regular tune-ups. Spark plugs
last as long as 100,000 miles; ignition systems are largely maintenance-free
and the cars onboard computer automatically adjusts things
like the air-fuel ratio and ignition timing to optimize performance
and economy. Unless the check engine light comes on,
or you notice a change in the way the engine sounds/performs (or
your mileage suddenly decreases) you should not worry about tune-ups
until the time/mileage interval specified in your vehicle owners
just change the oil and air filter (when needed) and keep the tires
inflated. Thats usually all you need to worry about.
your car before you drive off
In the days
when cars were fed fuel by carburetors (and took several minutes
to reach normal operating temperature) this was a good rule to follow.
But cars havent come with carbs since the late 1980s
a quarter century ago and a modern car reaches normal operating
temperature within moments of start-up. Idling the engine for several
minutes actually wastes fuel because it takes longer for the engine
to warm up and (among other things) reduces the efficiency
of the catalytic converters, which take longer to light off
(reach the temperature necessary for them to efficiently process
the exhaust) which in turn reduces operating efficiency and
thus, increases fuel consumption as well as emissions output.
The right thing
to do is to get in, start the car and drive it.
regular gas saves money
This is only
true if your vehicle was designed to burn regular unleaded. If,
however, you own a vehicle designed to run on high-octane premium
fuel, filling up with regular is a bad idea because your engines
efficiency will be reduced and youll probably end up
getting worse gas mileage, as well as reduced performance. The engines
computer will dial back ignition timing and other parameters to
compensate for the lower octane fuel, which means it will not be
operating at peal efficiency which means, you end up using
more gas. The kicker is, you also get dialed-back performance.
as counterproductive, on the flip side, to burn premium gas in an
engine built to run on regular. You wont get more performance
and you may see a mileage loss as well as the loss
youll pay up front for buying the higher-cost premium fuel.
the fuel economy potential of any engine, use the type of fuel it
was designed to burn whether that fuel is 87 octane regular
or 93 octane premium.
in or bolted on, the miracle mileage boosters you see
advertised on TV or online have (so far) invariably been shown to
be bogus. Think about it: If the car companies could up the fuel
economy of their cars by 5 or 10 MPG (or even 2 or 3 MPG) simply
by adding a $10 magnet to the fuel line or a vortex
to the air intake, why would they not install the thing at the factory?
Theyd meet their CAFE compliance targets (or get closer) at
little to no cost and without having to re-invent the wheel. But
they dont and that ought to tell you something.
garbage out of your trunk
The more weight
youre hauling, the more gas youll be using. Only carry
with you what you need to carry with you. Dont use your trunk
or pick-up bed for long-term storage. You might even consider removing
the full-size spare (if your car came with one) and carrying a couple
of cans of Fix-a-Flat instead. If you have a pick-up, you can probably
remove the tailgate and shed 50 pounds or so (which is what will
save you gas, not improved airflow).
Not just engine
oil but also manual transmission and axle lube. Synthetics have
better flow characteristics at extreme temperatures of cold and
hot, which reduces friction, which increases fuel efficiency (as
well as performance) and also reduces wear. The difference in smoothness/operating
characteristics, synthetic-equipped vs. not, is especially noticeable
in very cold weather. The math also works out more favorably when
were talking manual transmission/axle lubes which typically
only need to be done once every 30,000 miles or so (and maybe much
longer than that) vs. engine oil changes, which usually need to
be done once every 6,000 miles or so.
your engine if you expect to be idling for more than 30 seconds
gas by shutting down the gas side of the gas-electric powertrain
when the car comes to a stop. You can do the same thing without
all the high-tech assistance of a computer or the expense
of buying a new Prius. Shutting off the engine when you find yourself
stuck in traffic or hit a really long red light can reduce your
overall fuel consumption by as much as 5 percent. Just be aware
that you may also reduce the life of your starter motor and
youre working your cars battery harder than you otherwise
would, which could mean it dies sooner than it otherwise would have.
run your AC; roll down your windows instead
This is a maybe
yes, maybe no fuel saving suggestion. Older vehicles
generally, those built prior to the mid-1980s had AC systems
that were very power hungry, with huge compressors that took a lot
of energy to drive them. If youve driven such a car, you may
recall actually feeling the load on the engine when the AC was turned
on. If you have one of these old cars, you can indeed save some
gas by limiting the use of your AC. But with modern cars, the potential
fuel savings are lower because the AC systems in modern cars are
much more efficient. They dont load the engine nearly as much
and you might actually end up burning more fuel by rolling
down the windows and increasing the cars aerodynamic drag.
Rule of thumb: If your car is a 1990 model or newer, running the
AC probably wont increase your fuel consumption much
if its even noticeable at all.
car washed and waxed
believe a clean car drives better than a dirty one and they
may be on to something. A smooth, clean surface cuts through the
wind more efficiently than a bumpy lumpy one. Increased wind resistance
means higher fuel bills though the increase is probably very
small, for the most part. With one exception: If you have a truck
or SUV and have taken it off-roading, caked-on mud clinging to the
undercarriage and fenderwells can add a surprising amount of weight
to the vehicle as well as increase drag. A session with a
power washer can get your fuel bills back to where they ought to
with permission from EricPetersAutos.com.
[send him mail] is an automotive
columnist and author of Automotive
Atrocities and Road Hogs (2011). Visit his
© 2011 Eric Peters
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