Saving Gas: Tips for Driving Stretching Your Fuel Mileage

As gasoline has surpassed the $4.00 a gallon mark with no relief in sight there has been a lot coverage given to ways to increase your fuel economy. The easiest, switching to a smaller vehicle, is not an option for many of us, nor is simply driving less. But something that is an option for all of us is changing our driving habits. Here are some proven tips to get the more out of every gallon of gasoline.

The Gasoline

The gasoline that you use is one important factor. Many people do not understand what octane rating is, and what effect it has on a car's engine. In simplest terms, a fuel's octane rating measures its resistance to combustion. The higher the octane rating the more resistant the gasoline is. High performance engines require high octane gasoline to prevent something called pre-detonation, or what our grandfathers called "knocks and pings". Pre-detonation occurs when the fuel-air mixture ignites before the piston has reached the top of the compression stroke. This results in lower power and could damage engine parts.

Very few modern car engines need high octane gasoline. They are specifically designed and tuned to operate most efficiently on 87 Octane, regular unleaded. Putting a higher octane fuel in a car designed for regular will result in incomplete burning, fouled spark plugs higher emissions, and wasted money. In most cars you will actually get lower gas mileage on high octane fuel. So step one is to check your owner's manual and use only the gasoline that it specifies.

Maintenance

We hear it over and over. Be good to your car and it will be good to you. Proper maintenance is vital to getting good fuel economy. Again consult your owner's manual to determine the recommended maintenance cycle and stick to it. Beyond that one of the most vital things you can do to help improve fuel economy is proper tire inflation. Every driver should have a pressure gauge in the car and should check the tire pressures at least every other week. A properly inflated tire rolls more easily and lets your engine maintain your speed with less effort, therefore using less fuel.

The air filter is vital. A clogged air filter will not draw in as much air during each intake stroke and will result in a fuel mixture that is too rich. This means wasted fuel. Change the filter according to the manufacturer's recommendations. One option for many cars is the "cold air filter" This is a simple add on to your car's intake system that relocates the air intake away from the heat of the engine resulting in cooler, denser air being fed into it and increasing both horsepower and fuel economy. There are some disadvantages to it though. In some climates the relocated filter is subject to icing, and if not installed properly water can be drawn into the intake from driving through a puddle.

Make sure that your belts, hoses and cooling system are also properly maintained. Slipping belts, overworked pumps, and a cooling system that is not working correctly all conspire to make your engine strain harder to perform the same work.

Driving Habits

This is where the rubber meets the road as it were. Recently a fad called hypermiling as come onto fashion. While many of the things they attempt are common sense, some of them are flat out dangerous and illegal. What follows are some common sense driving habits that will increase your mileage without putting you or other drivers at risk.

1. The first thing to do is plan the trip. Make sure you know where you are going and how you intend to get there. Check the traffic reports for anything that may require you to reroute your trip to avoid sitting in traffic. Also try to combine trips whenever possible. Every time that engine turns over it costs money, so it follows that getting as much out of each trip as possible will save gas and cash.

2. Always remember that a car sitting still with the engine running gets zero miles per gallon. Do not start the car until you are actually ready to get moving. Adjust your seat and mirrors, store your coffee and buckle your seatbelt, then start the engine. Do not leave the car idling for more than a minute. If you have to run back into the house for something, shut the car off.

3. A car is not meant to be the same temperature as your refrigerator. In many places AC is an absolute necessity, but there is usually no need to run it full blast whenever you are in the car. Invest in a windshield sunshade, this will lower the temperature inside the car when it has been sitting in the sun and will let you reduce the amount of AC you will need to cool the car down. The trick is to flush the hot air out quickly. Crack the windows slightly and run the AC at maximum for a few minutes. Once the temperature is tolerable close the windows and adjust the AC to a comfortable setting, then turn it down one more notch. There is a lot of debate as to whether windows down or AC is more fuel efficient, but as was demonstrated on the show Mythbusters windows up and AC on is more efficient at highway speeds, while at lower speeds windows down is more efficient.

4. On the highway drive the speed limit. Fuel efficiency drops as speed increases. According to the Department of Energy a typical car is most efficient at 55MPH, at 70MPH it is 17% less efficient. But more than this, aggressive driving, weaving, and accelerating rapidly all drastically reduce fuel economy. Everyone should strive to handle their cars like NASCAR drivers, just not as fast, or close to the people around them. Smooth and efficient is the key. Use the cruise control whenever possible. It will hold a steady speed more efficiently than most drivers can and that means better economy. Keep your eyes up and focused on the road ahead. This is not only important for safety but will help you plot your course to avoid unnecessary speed changes.

5. In town is where it gets most interesting and the rewards of driving efficiently can be greatest. First put down the cell phone, don't get too involved in the radio, and concentrate on driving. As you are heading down the road stay focused. Driving the speed limit in town is more important than on the highway. In most cities the lights are timed to the speed limit. If traffic is not too heavy and you are going the right speed, you will make all of the lights, avoiding that zero mile per gallon idling at the red lights. If the light turns red at the next intersection, take your foot off of the gas and let the car coast to the intersection. You will not lose more than five miles an hour in speed, but the engine will work less and that saves fuel. At the stoplight some people will shift to neutral. This decouples the engine from the transmission and will also reduce fuel consumption, but there is a debate over whether this damages the engine or not. I leave it to the individual driver to decide if this is a good idea, but technology to automatically shift the car to neutral is now being included on some 2008 vehicles. When leaving the stoplight there is no need to bolt up to the speed limit as fast as possible. Smooth and steady application on the accelerator will again greatly increase fuel mileage.

To demonstrate the benefit of these techniques, I own a 2006 Nissan Frontier with a 4 liter 6 cylinder engine. It is EPA rated at 15MPG in the city and 20MPG on the highway (19 combined) It has an 18 Gallon fuel tank which means I should be able to drive 342 miles on a tank of gas. I routinely get 22MPG or better and can drive 400 miles on a tank of gas. That extra three miles per gallon is a 16% increase in fuel economy, when gas is $4.01 a gallon, that's like paying $3.37 a gallon. Still not a bargain, but it hurts a little less. Practice some of these methods and you will find a little extra money in your pocket each month, and you might find that you have become a better, safer driver to boot.