Gas Saving Tips & Myths

Being a car freak I thought I would list a few tips to help you save some gas along with some myths that either don’t work or can cause other problems. Just keep in mind, these are not "cumulative savings" so you are not going to get 50% better mileage by following all of them. Just check them out and decide which ones you think area good bang for the convenience buck.

Tips

1. Check and fill your tires. It won’t put gas in your tank like some people believe, but it does help you save what gas you have. This one can save you up to 10% so it’s worth a minute to check and fill to the proper pressure. The important part of this is “to the proper pressure”. Don’t fill your tires to the pressure listed on the side of the tire. That is the maximum pressure the tire can hold. You can usually find the correct pressure on a sticker that is on the driver’s door or door jamb. Some cars have the sticker under the hood or trunk lid so look there if you don’t see it on the driver’s door. Also pay close attention. Many cars have different pressures in the front and rear tires. My wife’s car takes 29psi up front and 36psi in back so it can be a pretty big difference. This is also important for tire wear and safety.
   
   
   
2. Take it easy on the gas. A lead foot really drinks gas. When you are going from a dead stop, the engine has to work hard for the car to gain momentum. If you hit the gas hard the engine is trying to push out the torque so it increases the fuel level to achieve this. If you can take it a little easier on the gas pedal you can save up to 20%. This one is totally dependant on the car. In my wife's car it yields a 5% increase but in our small SUV it yields 20%. The higher yields will tend to come from SUVs and luxury cars while lower yields will tend to come from sports cars because of the way the computers are programmed in the different types of vehicles.
   
   
3. Use the cruise when possible. When you use the cruise control, the car's computer manages the acceleration. The reason this can help is a driver has a tendency to push the gas pedal in and out constantly. This is caused by bumps in the road, fatigue, trying to keep up with the guy in front of you, etc. If you want to see how much this happens, pay close attention to what your foot is doing the next time you are driving down the freeway. You will be surprised. When you use the cruise, the computer only hits the gas when it feels the car actually slow down. It keeps a steady pace so you can save up to 10% by using the cruise control when it's safe to do so. Don't forget, never use the cruise control in the rain.
   
   
4. Turn off the compressor when you are sitting still if you can. There is a button in nearly every car to turn off the A/C compressor. It's usually the one with a snow flake on it. Turning it off when stopped or in stop & go traffic helps save gas and keeps the engine cooler. This one is only good for 1-2% improvement. The compressor is run by a belt so it is using engine power by putting “drag” on the engine. Turning off the compressor removes the drag and makes your engine run more efficiently. It also reduces the heat in the engine bay and keeps the engine cooler so it does not overheat while idling. An engine running above normal temperature is also inefficient so it is a good thing to keep the engine cool while idling. I say “if you can” because if it’s 95F outside it’s just not a good idea. Also, this only saves a little gas but when you’re waiting in line and running on empty it may keep you from having to push it to the pump.
   
   
5. Not for the faint of heart. There is one more thing you can do that can really boost your mileage, but it's not for the complete car novice. I have mentioned the car computer several times. Did you know you can tune your computer for different driving styles? There are tuners available in every car magazine that will change the timing, fuel/air ratios, etc. to meet your needs. You can make the engine more aggressive for sport driving and also tune it down so it is more efficient. Even though I will not recommend a specific tuner, I will recommend you get one that has presets. With those types of tuners you can choose the "mode" you want such as sport or economy and it does all of the computer adjustments for you. You must be careful if you do this. If you don't kow what you are doing and you start "tweeking" outside of those preset modes you can mess it up to where the car will not start. This can save a great deal of gas, up to 30%, but you have to take into account the cost of the tuner which is usually at least $300 to determine if it works for you.
   

Myths

1. Turn off the radio to save gas. The radio being on does not use more power from the engine. The radio is run off the battery and the battery is charged by the alternator. The alternator is always charging whether electric accessories are on or not. It has a switch inside that sends the power to the battery for recharge as needed, but even when that switch is off the alternator is still running off the engine so it is a constant drag on the engine no matter what.
   
   
2. Turn off the A/C and roll down the windows. Turning off the A/C will save a little on gas, but only if you are driving around 35mph or slower. After that the drag on the car actually uses more gas than running the A/C with the windows up would use. This one was finally debunked by the Myth Busters TV show.
   
   
3. Turn off the engine at stop lights or when waiting in a gas line. The line I was in today moved about every 1-2 minutes so people were turning off the engine then restarting every time they moved. In a line of 30 cars that's a lot of starts. I have also seen others on the Internet recommending turning off the engine while waiting at a stop light. The problem with doing that is every time you stop the engine, all of the oil drains down into the oil pan. The engine is left unprotected so when you restart, your engine wears more than when it is just running at normal temperature. Granted it is not as bad as a morning, cold start, but still worse than letting it run. All of the parts involved that wear can add up to thousands of dollars for replacement in order to save a few dollars in gas. This one is not really a myth because unlike the old carbureted engines, modern engines do not use more gas at start up than when idling so it does save a little gas, just not enough to cover the cost of a worn out starter, etc.
   
   
4. 55 saves gas. In the '70s the government instituted a nationwide 55mph speed limit to save gas. It may have worked a little (and I'm talking about very little) with carbureted cars back then, but it is not the case at all anymore. As a car speeds up, the wind force increases making it harder to push the car through the wind. The engine pushes against that force so it reaches a point where it requires so much energy just to push the car through the air that it negates the increased speed gained. Try not to glaze over on this part and hopefully I can make some sense of this. If you are driving a car at 10mph and it takes 1000rpm to keep moving at that speed then the engine will make 6000 revolutions every mile. With each revolution gas is sprayed into the cylinders. Next, if you are going 60mph and it requires 2500rpm to keep the car moving at that speed then the engine will make 2500 revolutions every mile. Since a car's computer manages how much gas is sprayed, you can see an across the board 55 saves gas is not even close. In our three cars, #1 gets the best gas mileage at about 80mph, #2 at bout 65mph and #3 at about 75mph. You would need to do some testing to figure out where you car does best, but overall 55 does not save gas.

Hope it helps.