Although there are practical steps you can take to increase gas mileage, the Federal Trade Commission (FTC) warns you to be wary of any gas-saving claims for automotive devices or oil and gas additives. Even for the few gas-saving products that have been found to work, the savings have been small.
"Gas-Saving" Advertising Claims
Be skeptical of the following kinds of advertising claims.
* "This gas-saving product improves fuel economy by 20 percent."
Claims usually tout savings ranging from 12 to 25 percent. However, the U.S. Environmental Protection Agency (EPA) has evaluated or tested more than 100 alleged gas-saving devices and has not found any product that significantly improves gas mileage. In fact, some "gas-saving" products may damage a car's engine or cause substantial increases in exhaust emissions.
The gas-saving products on the market fall into clearly defined categories. Although the EPA has not tested or evaluated every product, it has tried to examine at least one product in each category. See "Devices Tested by EPA" at the end of this brochure for category descriptions and product names.
* "After installing your product on my car, I got an extra 4 miles [6.4 kilometers] per gallon [3.8 liters]."
Many ads feature glowing testimonials by satisfied customers. Yet, few consumers have the ability or the equipment to test for precise changes in gas mileage after installing a gas-saving product. Many variables affect fuel consumption, including traffic, road and weather conditions, and the car's condition.
For example, one consumer sent a letter to a company praising its "gas-saving" product. At the time the product was installed, however, the consumer also had received a complete engine tune-up - a fact not mentioned in the letter. The entire increase in gas mileage attributed to the "gas-saving" product may well have been the result of the tune-up alone. But from the ad, other consumers could not have known that.
* "This gas-saving device is approved by the Federal government."
No government agency endorses gas-saving products for cars. The most that can be claimed in advertising is that the U.S. EPA has reached certain conclusions about possible gas savings by testing the product or by evaluating the manufacturer's own test data. If the seller claims that its product has been evaluated by the EPA, ask for a copy of the EPA report, or check www.epa.gov for information. In some instances, false claims of EPA testing or approval have been made.
Product Complaints and Refunds
If you're dissatisfied with a gas-saving product, contact the manufacturer and ask for a refund. Most companies offer money-back guarantees. Contact the company, even if the guarantee period has expired.
If you're not satisfied with the company's response, contact your local or state consumer protection agency or the Better Business Bureau.
U.S. EPA Evaluation Efforts
The U.S. EPA evaluates or tests products to determine whether their use will result in any significant improvement or detriment to fuel economy. However, the U.S. EPA cannot say what effect gas-saving products will have on a vehicle over time because it hasn't conducted any durability tests. It's possible that some products may harm the car or may otherwise adversely affect its performance. In fact, today's vehicles' emission control systems are very sophisticated and complex. They have On Board Diagnostic features that alert the driver to problems associated with the emission control and fuel delivery systems. Retrofit products may have an adverse effect on these systems.
Devices Tested by U.S. EPA
As of December 2005, the following list categorizes various types of "gas-saving" products, explains how they're used and gives product names. Those with asterisks may save measurable, but small, amounts of gas. All others have been found not to increase fuel economy.
Air Bleed Devices. These devices bleed air into the carburetor. They usually are installed in the Positive Crankcase Ventilation line or as a replacement for idle-mixture screws.
The U.S. EPA has evaluated the following products: ADAKS Vacuum Breaker Air Bleed; Air-Jet Air Bleed; Aquablast Wyman Valve Air Bleed; Auto-Miser; Ball-Matic Air Bleed; Berg Air Bleed; Brisko PCV; Cyclone-Z; Econo Needle Air Bleed; Econo-Jet Air Bleed Idle Screws; Fuel Max*; Gas Saving Device; Grancor Air Computer; Hot Tip; Landrum Mini-Carb; Landrum Retrofit Air Bleed; Mini Turbocharger Air Bleed; Monocar HC Control Air Bleed; Peterman Air Bleed; Pollution Master Air Bleed; Ram-Jet; Turbo-Dyne G.R. Valve.
Vapor Bleed Devices. These devices are similar to the air bleed devices, except that induced air is bubbled through a container of a water and anti-freeze mixture, usually located in the engine compartment.
The U.S. EPA has evaluated: Atomized Vapor Injector; Frantz Vapor Injection System; Hydro-Vac: POWERFUeL; Mark II Vapor Injection System; Platinum Gasaver; V-70 Vapor Injector; SCATPAC Vacuum Vapor Induction System: Econo-Mist Vacuum Vapor Injection System; Turbo Vapor Injection System.
Liquid Injection. These products add liquid into the fuel/air intake system and not directly into the combustion chamber.
The U.S. EPA has evaluated: Goodman Engine System-Model 1800; Waag-Injection System*.
Ignition Devices. These devices are attached to the ignition system or are used to replace original equipment or parts.
The U.S. EPA has evaluated: Autosaver; Baur Condenser; BIAP Electronic Ignition Unit; Fuel Economizer; Magna Flash Ignition Control System; Paser Magnum/Paser 500/Paser 500 HEI; Special Formula Ignition Advance Springs.
Fuel Line Devices (heaters or coolers). These devices heat the fuel before it enters the carburetor. Usually, the fuel is heated by the engine coolant or by the exhaust or electrical system.
The U.S. EPA has evaluated: FuelXpander; Gas Meiser I; Greer Fuel Preheater; Jacona Fuel System; Optimizer; Russell Fuelmiser.
Fuel Line Devices (magnets). These magnetic devices, clamped to the outside of the fuel line or installed in the fuel line, claim to change the molecular structure of gasoline.
The U.S. EPA has evaluated: PETRO-MIZER; POLARION-X; Super-Mag Fuel Extender; Wickliff Polarizer [fuel line magnet/intake air magnet].
Fuel Line Devices (metallic). Typically, these devices contain several dissimilar metals that are installed in the fuel line, supposedly causing ionization of the fuel.
The U.S. EPA has evaluated: Malpassi Filter King [fuel pressure regulator]; Moleculetor.
Mixture Enhancers (under the carburetor). These devices are mounted between the carburetor and intake manifold and supposedly enhance the mixing or vaporization of the air/fuel mixture.
The U.S. EPA has evaluated: Energy Gas Saver; Environmental Fuel Saver; Gas Saving and Emission Control Improvement Device; Glynn-50; Hydro-Catalyst Pre-Combustion Catalyst System; PETROMIZER SYSTEM; Sav-A-Mile; Spritzer; Turbo-Carb; Turbocarb.
Mixture Enhancers (others). These devices make some general modifications to the vehicle intake system.
The U.S. EPA has evaluated: Basko Enginecoat; Dresser Economizer; Electro-Dyne Superchoke; Filtron Urethane Foam Filter; Lamkin Fuel Metering Device; Smith Power and Deceleration Governor.
Internal Engine Modifications. These devices make physical or mechanical function changes to the engine.
The U.S. EPA has evaluated: ACDS Automotive Cylinder Deactivation System*; Dresser Economizer; MSU Cylinder Deactivation*.
Accessory Drive Modifiers. These devices reduce power to specific auto accessories.
The U.S. EPA has evaluated: Morse Constant Speed Accessory Drive **; P.A.S.S. Kit**; PASS Master Vehicle Air Conditioner**.
Fuels and Fuel Additives. These materials are added to the gas tank.
The U.S. EPA has evaluated: Bycosin; EI-5 Fuel Additive; Fuelon Power; Johnson Fuel Additive; NRG #1 Fuel Additive; QEI 400 Fuel Additive; Rolfite Upgrade Fuel Additive; Sta-Power Fuel Additive; Stargas Fuel Additive; SYNeRGy-1; Technol G Fuel Additive; ULX-15/ULX-15D; Vareb 10 Fuel Additive; XRG #1 Fuel Additive.
Oils and Oil Additives. Usually these materials are poured into the crankcase.
The U.S. EPA has evaluated: Analube Synthetic Lubricant; Tephguard.
Driving Habit Modifiers. These are lights or sound devices to tell the driver to reduce acceleration or to shift gears.
The U.S. EPA has evaluated: AUTOTHERM**; Fuel Conservation Device; Gastell; IDALERT**.
The U.S. EPA has evaluated: BRAKE-EZ; Dynamix; Fuel Maximiser; Gyroscopic Wheel Cover; Kamei Spoilers**; Kat's Engine Heater; Lee Exhaust and Fuel Gasification EGR; Mesco Moisture Extraction System; P.S.C.U. 01 Device; Treis Emulsifier.
* Indicated a very small improvement in fuel economy but with an increase in exhaust emissions. According to Federal regulations, installation of this device could be considered illegal tampering.
** Indicated a very small improvement in fuel economy without an increase in exhaust emissions. However, cost-effectiveness must be determined by the consumer for a particular application.
For More Information
For information about U.S. EPA test procedures and test results, visit www.epa.gov/otaq/consumer.htm or write: Verification and Compliance Division, Office of Transportation and Air Quality, Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; or call: 734-214-4925.
Source: By Consumer Energy Center of California