As fuel prices are soaring to $4.00 a gallon or more, we all need to conserve and reduce fuel waste and save money. No one thing will magically increase mileage. The combination of several different things most likely will. Here are a few tips. We do not guarantee any modification will improve
economy but it is our opinion these tip will help.
There are several gadgets on the market that are a complete waste of money. One is putting magnets on the fuel line. Another is a vane which is suppose to swirl the air into the engine. Swirling the air only serves to slow and limit the airflow. (see drawing below) There is no fuel in the airstream until it reaches a
point just before the valve. There is no way any amount of swirling can travel from the air tube, past the throttle body, and it's butterfly valve which is nearly closed at crusing speeds, into a large plenum, then turn 90 degrees and split going into 4 separate runners each 12-18 inches long. Each runner then curves and diverts into a smaller runner and into the intake port of the cylinder head where it will make another 90 degree turn to flow past the intake valve and turn again into
The idea of swirl is to keep the fuel atomized. Since there is no fuel until right before the intake valve, it would do no good even if it swirled
all the way down. Swirl in the cylinder and combustion chamber is handled by the offset of the valve and the offset of the low speed intake runner. I'd like to see an actual scientific test of this device on a chassis dyno.
Some people may actually think they get better mileage. They put one of these devices on, and then are conscience of their driving habits
and drive easier getting a bit better mileage. Do some research before spending you hard earned money on something that doesn't work. The only way to improve mileage is to stick to the basics. Make the combustion process more efficient and to reduce any forces which cost power, friction, and drag, either to the engine or the vehicle.
* Mechanics: First of all, your vehicle needs to be in good mechanical shape. If the plugs and wires have been there for 5 years, the oil hasn't been changed as long as you can remember, and your tires are worn off at an angle, you need to do some maintenance.
* Air Filter: The air filter needs to be clean. Either replace it with a new stock paper filter or a free flowing aftermarket filter like a K&N that is washable. Do not over oil these as oil can get on the air flow sensor wires.
* Air Flow Meter: You need to check the condition of the air flow meter. In the top, there will be a small round opening with 2 small wires inside (See picture below). These are the heated wires that tell the computer how much air is entering the engine. They need to be clean to
work properly. The wires should look silver in color. If they are black, they are coated with dirt or oil and need to be cleaned. These are easily broken so if you have any doubts of your abilities, take it to a garage. These sensors are very expensive. How I clean them is to remove the air flow meter and spray the sensor wires with a can of carb cleaner like Gumout. Spray until they are clean and then spray off with a brake cleaner which dries and leaves no residue. DO NOT touch the wires with anything! Let them air dry and don't use compressed air.
* Oxygen Sensor: The primary (upstream) oxygen sensor controls the mixture at part throttle. Oxygen sensors lose their ability to adjust themselves properly after a while. For more information, see this link: http://www.boschautoparts.com/Resources/FAQS/OxygenSensors.htm. You could have a garage check it or it may be just as cheap to just replace it with a new one. The 2nd O2 sensor just monitors the efficiency of the catalytic converter.
* Fuel Injectors: Your fuel injectors must be clean to atomize the fuel and provide the correct air/fuel
ratio. You can have them cleaned at a garage where they hook up a can of cleaner on the fuel rail and run the engine directly off of it. The best way is to use an in tank cleaner. The best I have used it Chevron Techron available at most auto parts stores for about $10 for the larger bottle. It's the only one that I have used that actually made a difference in the way the engine runs. I usually run it a bit
stronger than what the manufacturer calls for and fill up the tank. Then run the tank down to about 1/8 or so on the cleaner. If you keep filling it up, you'll just dilute the cleaner. I like to run this about every other oil change. There are many cheap cleaners on the market that seem to do nothing.
* Synthetic oil: Use a good brand of synthetic oil. Use a thin viscosity such as 5w20. This reduces the pumping forces of the oil pump and cuts frictional drag in the engine. Keep your oil changed. Personally, I change pure synthetic oils at about 5,000 miles and have seen no wear or sludge in engines that had well over 200,000 miles on them. Synthetic trans fluid will also help your transmission, either manual or automatic. I have
also used an additive called ProBlend in the oil that seems to cut friction and help the fuel economy. It definitely reduced the oil temperature (measured with a gauge).
* Spark Plugs: I know some say the plugs last 100,000 miles but at that time, they won't be working well. Plugs are cheap and it doesn't hurt
to replace them more often. I replace them once a year. Premium plugs may be better and will last longer without the gap eroding away. I prefer the dual-gap Bosch Plus 2 plugs. They are side gapped and help prevent shrouding the spark in the combustion chamber. Also, if you use better spark plug wires, you can open the gap a little for a larger spark. The Bosch plugs are difficult to regap and it is suggested not to attempt it.
* Spark Plug Wires: Many cheap and factory wire sets are carbon core. They
have quite a bit of internal resistance and do tend to break down after a while. Wires can easily be checked with an ohm meter measuring the resistance. The resistance will vary by the length. Just figure ohms per inch. The best wires are the spiral core. They have a spirally wound connector that reduces the electrical resistance without setting up any electromagnetic signals which can effect the computer and radio. (Solid wire core spark plug
wires cannot be used in modern vehicles with electronics) Spiral core wires last much longer and only have about 14% of the resistance of carbon core wires. This allows more energy from the coil to reach the plugs providing a hotter spark. With these wires, you can open the plug gaps a little more for a better burn. This combination smoothes the engine out, especially at idle, and improves part throttle torque and fuel economy.
* Underdrive Crankshaft Pulley: An underdrive crank pulley reduces the drag of the belt driven accessories and power loss on the engine. Everything that the engine has to turn takes power away from the crankshaft. You can reduce this by over half. This really helps when running the air conditioner. Keep in
mind that the alternator will not charge much at low rpms and you will need to take steps to reduce the electrical draw on the system. For instance, if you were stuck in traffic for a long period of time, just put the trans in neutral and raise the rpms up to say 2,000 for a few minutes, or about the same engine speed as if the car were being driven. This would be a small inconvience if only done occasionally considering the gains in performance and fuel savings. In normal everyday driving,
you need not to do anything different.
* Alignment: The alignment was reset for minimum rolling resistance, not to factory specs, and the tires were inflated to the maximum
recommended pressure. For maximum economy, I set the camber and toe-in to near zero with the vehicle loaded as it is normally driven, including the passengers. The front toe-in can be set just a touch wide and the deflection in the front end bushings will allow it to pull back straight under power. There may be a slight reduction in handling but it will reduce rolling resistance. (You be the judge)
* Brakes: Proper brake maintenance will allow the vehicle roll easier. The brakes should not drag and the wheels should roll freely. The fron calibers slide on 2 screw in pins (bolts). After a while, these will become corroded and not allow the caliper to move freely, holding the
brake pads against the rotor. Most of the time, these areas are not cleaned or lubed during a brake job. My solution is to remove the calipers. Then press out the 2 retaining pins that are in rubber boots. (see picture below) All these parts needs to be cleaned. Wire brush the pins if necessary. Clean out the holes in the calipers where these parts go. Then (the most important part) lube the pins throughly with
high temperature silicone brake lube. DO NOT use regular grease because the brakes get very hot and that grease will melt and run off and what's left will bake on After assembling the brakes, the calipers (less pads) should slide in and out easily without much resistance. After installing the pads, they should just lightly touch the rotors and the wheels should turn easily. Also, put a little lube where the caliper sits on the strut.
* Tires: Check your inflation pressures once a week. You may want to increase the pressure over the recommendation for the vehicle.
Usually, this will reduce rolling resistance. NEVER allow the pressure to exceed the maximum pressure shown on the sidewall of the tires! Keep in mind, higher inflated tires can have less contact patch on the pavement and may reduce traction in some cases. If you plan to replace your tires, do some research and try to find some with reduced rolling resistance. A good source of info is www.tirerack.com
* Automatic Transmission: We use the Automatic Transmission Controller to keep the torque converter locked whenever the transmission is in high gear. This prevents the converter from constantly locking and unlocking and prevents converter slippage helping fuel economy when driven on the highway.
* Fuel: In most cases running premium fuel will not help economy. The only thing "Premium" means is higher a octane rating which is the
fuel's resistance to detonation or knock in the engine. Unless the engine is set up for premium (ignition timing and high compression) and the use of regular causes the ignition timing to be retarded due to the knock sensor, it will not help economy and will just cost you more money. In an engine that doesn't need it, premium will not make any more power than regular.
* Weight: Clean out your car. It takes power and fuel to pull those extra pounds. I have heard about a 2% reduction in fuel economy for every additional 100 lbs.
* Driving Style: How you drive drastically affects mileage. In other vehicles, I've seen at least a 30% drop in fuel economy just by bad driving habits. Do slower accelerations and plan you stops ahead of time and allow the car to coast down a bit using the stored up inertia. On the interstate, I usually let the speed increase when going down hills and let it fall off a little going up hills. Let gravity help accelerate you
car and use that inertia to help climb the next incline. Just don't speed.
Also, driving slower on the highway will save some fuel. I don't suggest driving much slower than the posted speed limit, within 5mph. Just avoid running 10-15mph over. The aerodynamic drag on the vehicle is what hurts fuel economy. The drag force basically increases with the
cube of the speed. For instance, it doesn't take a 50% increase in power to run 90mph instaed of 60. It would be more like 3.4 times the power to overcome the aerodynamic drag. The amount of actual fuel used will depend upon a number of factors including the rpm and efficiency of the engine at various speeds but as a general rule, going faster above 30-35 mph cost fuel.
Keep your windows rolled up while driving at speeds over 35-40 mph. It tales more power to fight the aerodynamic drag that to power the air conditioner. Try using the vents and fan for air until it gets hot enough to turn on the air conditioner. Also, don't allow the engine to idle
for extended periods of time. Turn it off if you are going to be stopped for over a couple of minutes.