The Ultimate Fuel-saving Device Hoax Quiz

Estimated Completion Time
2 min
The Ultimate Fuel-saving Device Hoax Quiz
Image: Lauren Nicole/DigitalVision/Getty Images

About This Quiz

Every driver would like to save a few dollars on gas. Consequently, the market for fuel-saving devices -- and fuel-saving hoaxes -- is large. See how well you can separate fact from fiction with our quiz on fuel-saving device hoaxes!
What do fuel ionizers and fuel catalysts claim to do?
minimize fuel flow using ionic fields
dissolve smog-producing agents in fuel
alter fuel to make it burn more efficiently
Correct Answer
Wrong Answer

A variety of devices claim that they use ionic charges or catalytic action to alter fuel into a more efficient form. An equal variety of reasons, from onboard engine computer adjustments to basic chemistry, make these claims dubious at best.

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Is it more efficient to roll down the windows or use the air conditioner?
roll down the windows
use the air conditioner
use the air conditioner when at speed, but roll down the windows in start-and-stop traffic
Correct Answer
Wrong Answer

While running your air conditioner in stop-and-start driving conditions will burn slightly more gas than normal, the drag of driving at highway speeds with the windows down is less efficient than using the air conditioning when underway.

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Where was water injection first used?
in heavy locomotives in the 1940s
in propeller-driven fighters in World War I
in propeller-driven fighters in World War II
Correct Answer
Wrong Answer

Water injection was developed during World War II to help fighter pilots prevent detonation in high-compression engines running on low-octane gas. The same technology can protect a high-performance car engine, but it does little for mileage.

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How does hydrogen compare to gasoline?
Hydrogen has higher specific energy and higher energy density than gasoline.
Hydrogen has lower specific energy and lower energy density than gasoline.
Hydrogen has higher specific energy but lower energy density than gasoline.
Correct Answer
Wrong Answer

While hydrogen carries more than 10 times the specific energy of gasoline, its low energy density means hydrogen is a much more difficult fuel to use for vehicles -- it's hard to store enough to provide adequate range.

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How efficient is electrolysis in a hydrogen generator in producing hydrogen?
about 25 to 40 percent efficient; not enough to produce fuel for transportation
efficient enough to replace 75 percent of a car's gasoline use
efficient enough to provide 30 percent of a car's gasoline use
Correct Answer
Wrong Answer

While electrolysis is a simple process for producing hydrogen from water, the hydrogen produced from the process is often 25 percent of the amount of energy required to make it.

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True or false: Petroleum fuels can be significantly altered by fuel-line magnets.
true
false
Correct Answer
Wrong Answer

Petroleum fuels are too stable to be significantly altered by something as small and simple as a magnet placed on a fuel line. Even if a magnet could produce a significant electrical field, it would be altered by the metal of the fuel line, the tank and its components.

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Do high-flow air filters improve fuel efficiency?
no, although they could increase horsepower
yes, they increase efficiency by 20 percent
no, they reduce mileage and horsepower
Correct Answer
Wrong Answer

While a high-flow air filter does reduce restrictions on an engine's intake, possibly increasing horsepower, the engine will compensate by injecting more fuel into the engine, negating any big fuel-saving claims.

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What does an intake vortex device actually do?
It limits horsepower and acts as a restrictor.
It increases horsepower by smoothing out intake airflow.
It increases horsepower by making intake airflow more turbulent.
Correct Answer
Wrong Answer

Intake vortex devices claim to improve fuel-air mix -- and efficiency -- by altering airflow into the engine. In reality, these often act as restrictor plates, limiting horsepower and wasting gas.

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How does an engine react to a vapor injector?
It will burn fuel more efficiently, thanks to the added vapor.
It will compensate for the added vapor by limiting fuel flow.
It will increase fuel flow to make the vapor mixture richer.
Correct Answer
Wrong Answer

A fuel vapor injector can cause a car's cylinders to run rich -- with too much fuel. The engine's computer will limit fuel flow, negating any advantage the injector claims to offer.

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True or false: Gasoline burns the same whether it's vaporized or in liquid form.
true
false
Correct Answer
Wrong Answer

Gasoline in liquid form burns too slowly to be useful for combustion, but vaporized gasoline burns at the high rate necessary to power an internal combustion engine.

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You Got:
/10
Lauren Nicole/DigitalVision/Getty Images