Gas Mileage Devices and Enhancers
Fact or Fiction?

As gas prices rise, and the concern for our environment grows, gas mileage devices spring up all over the Internet claiming to increase gas mileage by massive amounts, whether they be the ones listed below, the acetone claim, or the many water for gas devices advertised online.

However, are these products legitimate or scams?

EPA Testing of Gas Mileage Devices

• Air Bleed Devices
• Vapor Bleed Devices
• Liquid Injection
• Ignition Devices
• Fuel Line Devices - Heaters / Coolers
• Fuel Line Devices - Magnets
• Fuel Line Devices - Metallic
• Mixture Enhancers - Carburator
• Mixture Enhancers - Misc.
• Internal Engine Modifications
• Accessory Drive Modifiers
• Fuel Additives
• Oil Additives
• Driving Habit Modifiers
• Other

Of the 80+ gas mileage devices tested by the EPA, only 10 were showed to increase gas mileage, and even then, the improvements were incredibly small.

Some of these gas mileage enhancers not only increase gas mileage, but also harmful emissions that pollute the air.

"Which Gas Mileage Enhancers Work?"

However, when testing gas mileage devices, the EPA stated that the following did increase gas mileage a small, but measurable amount.

1. Fuel Max

   Listed as an air bleed device, the Fuel Max was the cause of a major lawsuit by consumers to the manufacturers and marketers of the product. According to the lawsuit, the Fuel Max company and its affiliates made claims that their device increased MPG by 27%, reduced emissions by 43%, and even gave the vehicle 10% more horsepower.

   However, the EPA tested the Fuel Max in 1981, and these claims couldn't be further from the truth. While it's true the device did increase gas mileage, the change was minimal, and while hydro-carbon emissions decreased slightly, the nitrogen oxide emissions went through the roof!

   Needless to say, the company that promoted and owned the Fuel Max product settled out of court.

2. Waag-Injection System

   The idea behind this system was to incorporate a 50% alcohol / water mixture. The Waag was the only vapor bleed device tested by the EPA that was able to boost gas mileage. While the increases were rather significant, the emissions were also incredibly high as well.

3. ACDS Automatic Cylinder Deactivation System

   A rather complex idea and design, the ACDS must be installed by a trained mechanic. The reason? It an Internal Engine Modification system, meaning changes are made to the engine itself.

   The ACDS was designed for 8 cylinder engines. The idea was to deactivate 4 out of 8 cylinders to increase gas mileage.

   The EPA tested this gas mileage device in 1981 and found that fuel economy did improve about 3-20% overall, according to two separate testing procedures. However, the emissions were raised so high that the device violates the Clean Air Act!

   The obscene increase in emissions isn't the only problem either. The modification to the engine caused by the ACDS create hazardous driving issues with the vehicle, including a reduction in braking power under certain road conditions. Yikes!

4. MSU Cylinder Deactivation

   This Internal Modification System gas mileage device is listed with the Federal Trade Commission as a product tested by the EPA. The findings were that the device increased gas mileage and emissions. However, I was unable to locate the EPA test paperwork and results to retrieve any details.

5. Morse Constant Speed Accessory Drive

   The Morse CSAD is an Accessory Drive Modifier. If you've read my driving tips, you know that having additional accessories, such as air conditioning and lights, running will decrease your MPG. The purpose of the CSAD gas mileage device is to increase gas mileage when the accessories are running.

   Two different tests were used for the CSAD to measure the difference of gas mileage and emissions with and without the device installed, and with and without the A/C and lights turned on.

   Overall, with the accessories turned on, an increased gas mileage of 6% was measured. Without the accessories on, the gas mileage either went down or went up an insignificant amount.

   Emissions also went up and down in variable ways. In one test, some harmful pollutants emitted from the vehicle were up to 218% greater than those without the device installed!

   As if that wasn't enough, engine temperature readings during highway tests were higher than normal.

6. P.A.S.S. Kit

   This gas mileage enhancer is also classified as an Accessory Drive Modifier. According to the Federal Trade Commission, the gas mileage improved slightly without any noticeable increase in harmful emissions.

7. PASS Master Vehicle Air Conditioner

   Another Accessory Drive Modifier, the PASS Master Vehicle Air Conditior was also labeled by the FTC as creating a small improvement in gas mileage without a significant increase in pollutants.

8. AUTOTHERM

   This Driving Habit Modifier is designed to notify the driver when he should shift gears, slow down, etc... in order to increase gas mileage. According to the FTC, the EPA tested this device and concluded that it showed a small improvement in gas mileage without significantly impacting emissions.

9. IDALERT

   The results from the IDALERT match those of the AUTOTHERM above.

10. Kamei Spoilers

    This unclassified gas mileage device was tested by the EPA with results matching those of the IDALERT.

Please note: #s 7-10 above will have more detailed information once the data from the EPA records has been researched. Until then, please visit the EPA Gas Mileage Devices and Enhancers Test Results Page for full reports on each of the gas mileage enhancers tested.

Return to Improve Gas Mileage Guide from Gas Mileage Devices