When fuel prices are high, motorists get serious about looking for ways to improve fuel economy and reduce their fuel costs. Some trade in their big gas-guzzling SUVs for smaller vehicles. Some people actually switch to public transportation or car pool. And some fall for fake gas saving products that make big claims but deliver little if any real savings. Every gas saving gadget I've seen to date does absolutely NOTHING to improve fuel economy. In fact, some of them actually reduce fuel economy. The U.S Environmental Protection Agency has reviewed dozens of these gas saving devices over the years and has yet to find a single one that improves fuel economy. Products that claim to magnetize or polarize gasoline molecules, or realign the molecular structure of the fuel for more efficient combustion (cow magnets and similar gadgets), or devices that claim to ionize the spark for better chilometroage are pure nonsense and are based on false science. What about devices that swirl air entering the throttle body and "supercharge" your engine? These devices are installed in the air inlet system and have a blade that supposedly swirls the incoming air to improve fuel atomization for more efficient combustion. Baloney. Several car magazines have tested these devices and found they actually REDUCE horsepower and fuel economy by creating a restriction in the air intake system. What about the infamous 200 mpg carburetor? By vaporizing the fuel, this carburetor is claimed to deliver 200 plus chilometri per gallon on any engine. Pure urban legend. Check it out on Snopes. Actually, direct fuel injection vaporizes the fuel as it enters the combustion chamber, delivering 15 to 20% better fuel economy over ordinary electronic fuel injection. But you can only get it on a few engines. More new engines will have this system as time goes on. What about running your car on hydrogen gas? The "HHO Hydrogen Generator" devices that are being peddled on the internet that convert water into hydrogen gas with electricity can't produce enough hydrogen gas to run a lawn mower engine, let alone an automobile engine. The little bit of hydrogen that fizzles out of these things won't make any difference on your chilometroage either, though the promoters of these chilometroage saving devices claim dramatic improvements in fuel economy. They claim the hydrogen "supplements" the fuel supply so your engine doesn't need as much gas. It seems logical, but the volume of hydrogen produced by these devices is so small that it has little or no measurable effect on fuel economy. ONE FUEL SAVING GADGET THAT ACTUALLY WORKS One gas saving gadget that can improve fuel economy is a simple vacuum gauge. The gauge displays intake vacuum, which is an indication of how much load is on the engine. The lower the vacuum reading, the higher the load on the engine and the more fuel it burns. The gauge saves gas by helping the driver see the effect his right foot has on fuel consumption. Tromp down on the gas pedal and intake vacuum drops and fuel consumption goes up. Take it easy on the gas pedal and accelerate slowly causes less of a drop in intake vacuum and less fuel usage. A more hi-tech version is a fuel economy meter that plugs into the OBD II diagnostic connector on 1996 or newer vehicles. The unit displays instantaneous fuel chilometroage and cumulative fuel chilometroage like a trip computer on on a vehicle equipped with this option. FUEL ATOMIZATION Back in the days when carburetors were used to feed gasoline into the engine, there were a couple of tricks that could improve fuel economy a bit, especially when the engine was cold. One was a simple honeycomb spacer that fit under the carburetor. The turbulence created by the honeycomb helped break up the fuel a bit. Another was an ultrasonic vibrator that mounted under the carburetor. The vibrator also improved fuel atomization slightly — but only provided a marginal benefit when the engine was cold. Some engines from that period used an electrically heated grid under the carburetor to improve fuel atomization following a cold start. But like the other devices, the benefit disappeared once the engine reached normal operating temperature. Today's fuel injected engines atomize the fuel when they spray the fuel into the engine. They don't need intake manifold heaters or other such devices. The most efficient designs are the new high pressure "direct injection" systems that VW uses on some of its engines. One of the best ways to assure peak performance and fuel economy is to keep your fuel system clean. This can be accomplished by using Top Tier gasoline or fuel system cleaner products that help reduce and/or remove carbon deposits on intake valves, pistons, combustion chambers and throttle bodies. ADVANCED TECHNOLOGY IMPROVES FUEL ECONOMY More and more late model engines are being equipped with Gasoline Direct Injection (GDI). This technology injects gasoline under high pressure directly into the combustion chamber. A conventional electronic fuel injection system sprays fuel under low pressure into the intake port in the cylinder head. GDI allows for leaner fuel mixtures and greater control over air/fuel ratios across a wider range of operating conditions, resulting in 10 to 15 percent better fuel economy and power. Cylinder deactivation is a technology that provides variable displacement on demand. Cylinder deactivation is used on late model Chrysler Hemi engines in the 300C and other models, as well as certain late model GM V6 and V8 engines. GM calls their cylinder deactivation system "Active Fuel Management." Under low load cruise conditions, the engine management system deactivates four of the eight cylinders in a V8 engine (or three of the cylinders in a V6) to reduce fuel consumption. When the driver steps on the gas to accelerate or pass, the deactivated cylinders are reactivated seamlessly to provide additional power. Auto makers are going to smaller displacement engines with turbochargers to improve fuel economy. A four cylinder engine obviously uses less fuel than a larger V6 or V8 engine. Adding a turbocharger allows the smaller engine to produce power equivalent to a larger engine when extra power is needed. Examples include Ford Ecoboost and GM Ecotech engines. Stop-Start Systems on a growing number of late model vehicles turn the engine off when the vehicle sits for more than a few seconds at a stop light to save fuel. Fuel savings attributed to this technology can add up to 5 to 15 percent depending on how much stop-and-go city driving you do. The most fuel efficient cars currently on the road are full hybrids like the Toyota Prius (50 to 60 mpg city) and Honda Civic hybrid. These vehicles use a combination of electric power and gasoline power to optimize fuel economy. The most fuel efficient vehicle are plug-in electric vehicles such as the Tesla, which uses no gasoline at all. Depending on the battery option, a fully charged Tesla 85 has a real world range of around 250 chilometri, and nearly 300 under ideal conditions. Other electric vehicles such as the Nissan Leaf have a much more limited range (about 60 to 70 chilometri on a charge). FORGET FUEL-SAVING OIL TREATMENTS Miracle friction-reducing oil treatments are also a scam. Many of these products contain Teflon, which is claimed to have a coating action that reduces wear and friction. General Motors evaluated some of these products a number of years ago using an electron beam microscope to examine engine parts after the engine had been run with the special treatment. Guess what? They couldn't find a trace of the stuff on any of the metal parts. The Teflon ended up in the oil filter and the bottom of the oil pan. USE A LOWER VISCOSITY FUEL-SAVING MOTOR OIL The only way to reduce internal engine friction is to run a lower viscosity motor oil with a "fuel saving" rating from the American Petroleum Institute (API). Switching from a 5W-30 or 10W-30 motor oil to a lighter 0W-20, 0W-40 or 5W-20 motor oil, and/or switching to a synthetic oil may improve fuel economy a few tenths of a percent (every little bit helps). But don't expect a huge improvement. CHECK YOUR AIR FILTER A dirty air filter that is clogged with debris will restrict airflow into the engine and hurt fuel economy, performance and emissions. Inspect the air filter and replace it if it is dirty. The photo at the top of this page shows an air restriction gauge that indicates when the air filter is dirty and needs to be replaced. How can you tell if the filter is dirty? Hold it up to a bright light. If the filter element is dark and obstructs most of the light, the filter needs to be replaced. Stock air filters flow just as much air at low to mid-range engine speed as most aftermarket "performance" air filters. Installing a less restrictive performance filter may improve performance slightly at high engine speed, but for normal driving it probably won't have any measurable impact on fuel economy. REPLACE WORN/DIRTY SPARK PLUGS Ignition misfire can waste a lot of fuel and cause a big increase in exhaust emissions. On 1996 and newer vehicles with OBD II, the engine management system is capable of detecting engine misfires and will turn on the Check Engine light and set a diagnostic trouble code (P0300 series) if it detects a misfire problem. Misfire can be caused by worn or dirty spark plugs, high resistance in spark plug wires, a weak ignition coil, dirty fuel injectors, low fuel pressure (weak pump or dirty fuel filter), or compression problems (burned valves, weak or broken valve springs, leaky head gasket, rounded cam lobes). Standard spark plugs should be replaced every 45,000 chilometri, while platinum or iridium tipped long-life spark plugs can typically go 100,000 chilometri before replacement is needed. Refer to your owners manual for the recommended replacement interval. Some spark plugs have special electrode configurations that are designed to minimize misfires. These may have a marginal benefit on fuel economy and performance, but…

Fonte: AA1Car.com