ALT-2 What Reduces Fuel Economy
There are four essential topics that must be visited when discussing fuel economy robbing aspects of automobiles. First and foremost is correct engine tuning, followed by driving habits, drag, and weight. Checking these areas can add miles per gallon to your fuel economy and help keep dollars in your wallet.
Engine tuning is probably most important. There are many, many problems that can have a drastic effect on your fuel economy. If you aren't a mechanic, you might never even notice there is a problem until you get ready to pay at the pump. If your car is averaging a great deal less than the stated fuel economy averages from your window sticker, you might want to have it checked out. A simple tuneup can save you a lot of money in the long run. Incorrect air/fuel mixture, obstructed PCV valve or catalytic converter, bad oxygen sensor, or even an extremely dirty air filter can have a detrimental effect on MPG.
Next on the list would have to be driving habits. This topic shouldn't have to be addressed too heavily. It's very simple. Don't drive like you are in an Indy car and your gas tank will thank you(and you might even save a buck or two on speeding tickets).
Next is drag. The most important area of your vehicle to check for aerodynamic or frictional drag is the tires. Keep your tires inflated to the manufacturer's recommended pressure stated on the tag inside your car's door and you will achieve optimal fuel economy from your tires. This is because an underinflated tire puts more surface area on the road. This equates to more drag. A properly inflated tire will also give you better handling and driveability on most surfaces.
As far as aerodynamics, the less things that stick up from the car, the less drag. This includes spoilers(especially those huge "The Fast and the Furious" wings), hood scoops, and bug deflectors. These will have a negligible effect on your fuel economy though, so unless you are just trying to squeeze every last mile out of that gallon of gas, these would be the last areas I would worry about. Same thing with the AC or heater, The AC compressor on most modern cars causes very little frictional drag on the engine, and you will probably not notice any difference at the pump with the AC on or off. The heat does run the AC compressor sometimes to get rid of moisture on the inside of the windshield. But once again, unless you are driving a 1965 Plymouth Fury with a 426 CID Max Wedge under the hood, go ahead and stay comfortable.
Last but not least is weight. Weight has a quite an effect on gas mileage. That's why those tiny Geo metros of yesteryear got almost 50 MPG and today's Toyota Corolla, one of the most fuel efficient gas automobiles built at present, gets barely 40 MPG. Sit them next to each other and you see that the Corolla looks like a monster truck compared to the Geo, and the substantially heavier(and safer) Corolla's 40 MPG looks all the more impressive. It is a simple fact that weight and gas mileage are inversely proportional. That's why you don't see overweight NASCAR drivers. The main thing for the consumer to consider is the junk in the trunk. Do you really need to haul around that 200 pound guitar amplifier? Hoping a concert might break out and you just want to be prepared? Unload that extra stuff, and only haul what you need. The main thing you can do to reduce weight, aside from not hauling around your freeloading friends, is to replace the factory steel wheels with alloys. Aluminum wheels tend to shed several pounds when replacing those steel stockers. A fiberglass hood can also drop around 11 pounds.
These tips can easily save you hundreds of dollars each year on gasoline. I'm not telling you to go crazy and start gutting your car to reduce the weight though. Just by doing a few inexpensive things, you will notice a difference. Just please, please don't be that guy who believes he is saving gas by driving down the highway with his tailgate down to reduce drag in the bed. Your windshield is already pushing the air over the bed and nothing short of removing the tailgate altogether is going to increase your MPG.
