Gasoline price: 7 truths and myths about saving fuel

Using the car less is the most obvious way to save money on gasoline, amid rising fuel prices in Brazil and around the world. But how else can you save fuel?

Check out five tips on how to do this.

1) Is 90 km/h the best speed to save fuel?

Many drivers find that driving at exactly 90 km/h is the fuel efficiency sweet spot. This idea appears on many websites and articles on the internet.

However, there is no ideal fixed driving speed, according to the RAC motorsport group.

The myth that 90 km/h would be the sweet spot arose in old fuel consumption tests, in which the use of gasoline was tested by cars at 90 and 120 km/h inside the city.

In these tests, the most efficient consumption was at 90 km/h, which led many to believe that this was always the best speed.

However, depending on the type and size of the vehicle, the RAC says the most efficient speed is between 72 and 80 km/h — speeds above the limits of most roads within cities.

2) Should I turn off the air conditioning?

If you’ve ever resisted the urge to turn on your car’s air conditioning on a hot summer day just to save fuel, you’ve done the right thing.

Extra energy is needed to power a car’s air conditioning system. Fuel consumption can increase by up to 10% with the air on, according to the British car association AA.

The impact may be more noticeable on shorter trips — that’s because the air conditioner has to use more energy initially to reduce the car’s internal temperature.

Opening the windows might be better, but that creates a different problem, aerodynamic drag. The engine needs to work harder to compensate for the air resistance created by the open windows.

If you have to choose between air conditioning or open windows, the best option depends on speed. Air conditioning is probably the best alternative above 80 km/h, because the faster you drive, the greater the resistance caused by open windows.

3) Does driving in neutral save fuel?

AA does not recommend that drivers drive in neutral or apply the clutch. This is unsafe for several reasons. Also, this practice is unlikely to save gasoline.

The British Automobile Association says most cars have electrical controls that cut off the fuel supply every time you take your foot off the accelerator – so there’s no gain from driving in neutral.

4) Does the cruise control save fuel?

Cruise control — a device that keeps the car at a constant speed without having to use the gas pedal — is often seen as a surefire way to save fuel, as it avoids unnecessary acceleration and sudden braking.

But it only works like that when driving on flat roads.

On other types of road you are more likely to run into hills and your cruise control will need to adjust to the change in incline, consuming more fuel in the process.

Normally, you take your foot off the accelerator when you see a downhill slope ahead, but since the cruise control can’t see it, it spends more time using energy, increasing fuel consumption.

5) Does wrong tire pressure increase gasoline consumption?

Low pressure tires cause an increase in gasoline consumption. The advice is to check your pressures frequently, especially before a long trip.

The correct pressure is in the car manual — and it is sometimes recommended to increase the pressure to the maximum if the car is loaded with several passengers and luggage.

However, any extra weight will consume additional fuel — so leave out anything you don’t need.

6) Do I need to replace gasoline with regular gasoline?

In the short term, additive gasoline does not represent any fuel savings, as it has the same proportion of ethanol and gasoline as the common fuel sold at the pump. The biggest difference is that additive gasoline includes some chemicals that serve as detergent and dispersants, removing dirt from the tank and expelling it out of the engine at the time of combustion.

In the long run, this can represent savings for the driver, as a cleaner engine is more efficient and requires less fuel to run.

7) Should I change gasoline to ethanol?

The general rule for those who can fill their car with both fuels is that ethanol needs to be priced below 70% of gasoline to compensate. So if gasoline is costing R$7, ethanol needs to cost less than R$4.90.

When gasoline is at R$8, ethanol needs to be cheaper than R$5.60. Research by the National Petroleum Agency shows that the price of ethanol is also rising — and that in most Brazilian states, it does not pay to switch from gasoline to ethanol.

This text was originally published here.