Acetone Additive to Gasoline and Increased MPG?

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Is it true that adding a few fluid ounces of pure acetone to 10 or 20 gallons of gasoline in your car increases fuel efficiency/MPG? Most mechanics and automotive experts will flatly tell you no, it does not. Yet there are many believers whom regularly ad


Fuel Additive for Greater Fuel Efficiency/MPG?

Several years ago and continuing to this day, rumors and allegations persist about adding 1-2 ounces to every 10 or 20 gallons of gasoline in internal combustion engines providing a notable MPG increase. Stories of increased MPG of 25-30% are not uncommon.

The ratio of acetone-to-gas used is very low, something like 1:3000 to 1:5000. The 'safe amount' of acetone to add works out to be around 1.5 to 2 ounces acetone per 10-gallons gasoline. Acetone addition to gasoline greatly decreases the surface tension of the gas, causing improved combustion and greater mileage.

But never add more than 3 ounces acetone to 10 gallons gasoline. -Acetone is a light molecule and its addition to gasoline in excess will raise the octane too high, causing a super-lean fuel mixture that will make your mileage and performance suffer.

Experts Says Adding Acetone Does Not Increase Fuel Mileage

Mechanics and automotive-combustion experts will tell you that adding acetone to your gas tank does nothing to increase mileage, likely reduces your mileage and that it may damage non-metal parts in your fuel delivery system. The caveat added is that adding acetone to your gas tank '...may damage your engine and void your car's warranty.'

Fuel Efficiency: Believers Say Acetone in Gasoline Increases MPG

Many people whom have tried adding acetone to their gas tank swear that it increases their MPG. They state that acetone addition causes their engines to run smoother and quieter while also providing a bit more horsepower. Those who believe are called misguided and mistaken while those whom don't believe are labeled part of some 'bigger conspiracy,' with claims of  '...being backed by 'Big Oil' ' to conspire to hide the truth.

Acetone Fuel Additive and Myth Busters

Adding acetone to automotive fuel for the purpose of increasing MPG was featured on an episode of Myth Busters and roundly defeated by the experiments they performed. The MPG actually decreased slightly when they used acetone. Critics of the show and the episode cite several factors in the show that likely caused the so-called 'scientific test' to fail. So, -who is right?

Advocates of acetone fuel additive say you want to use pure 100% acetone and not the OTC stuff you buy at the HBA section at the pharmacy. This acetone contains benzoate, which allegedly is bad for combustion. Others say that any acetone is better than no acetone at all, but they all agree that 100% pure acetone is best.

Potential Risks of Adding Acetone to your Gas Tank

Some gas tanks (I am told of certain models of Toyota, for example) have a plastic liner inside of the gas tank. This is an anti-static feature as well as a containment vessel to prevent gas tank rupture in the event of a rear-end collision.

It remains just possible that acetone might ever so slightly dissolve this plastic gas tank liner, and the effluent gets sucked into the fuel line, fuel injection system and possibly into your engine. Or, it may just clog everything causing the delivery of fuel to stall.

What is stated to possibly happen is that when acetone is added to gasoline it breaks-down the bond between hydrogen polymers, causing the plastic to weaken, melt and dissolve. This would be a very undesirable outcome of adding acetone, if this is what occurs. This scenario seems unlikely however.

Gasoline is Corrosive

Gasoline itself dissolves many substances and is itself quite corrosive to many materials. It remains possible that acetone addition to gas can slowly dissolve certain polymer plastics used in automotive fuel systems, plastics that raw gasoline does not adversely affect. It remains a curious fact however, that adding alcohol (ethanol, methanol) to your fuel system is known to be damaging and yet, -we do that every time we add fuel line conditioner/anti-freeze!

Rubber or polymer plastic O-rings where fuel lines are joined could melt, causing dangerous fuel leaks. The electric fuel pump in the gas tank could sustain damage from acetone contact. It is even stated that valve guides, stems and rings might be affected over the long term, causing the vehicle to leak and burn oil through the combustion cylinder.

It is more likely that if it does actually met or dissolve plastic parts, the goo would sooner gum-up delicate injector parts long before eroding a fuel line connection to the point of causing it to leak fuel or any of these other 'worse case' scenarios occur.

Either way, any of these outcomes would unfortunate and an expensive price to pay for experimenting with acetone addition.

Before attempting to add acetone to your gas tank for the purpose of increasing your MPG, know the risks. I invite you to read the site linked above, Pure Energy Systems (PES) report "Acetone In Fuel Said to Increase Mileage" and decide for yourself.

From their web article (cite: here) comes this reminder:

  • "Acetone is known to deteriorate cheap plastics and other substances.  While the components in a car's fuel system should be of high quality, and thus immune to any deleterious effects from exposure to acetone, be aware that "ideal" is not always the case in practice.  Be advised that not all systems have been tested against acetone.  Until such thorough testing has been accomplished and certified by a accredited authority, you assume your own liability for experimentally testing acetone in your particular system."