# Pure acetone increases gasmilage

Discussion in 'Chemistry' started by Syzygys, May 14, 2007.

1. ### AbsaneRocket SurgeonValued Senior Member

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I once put premium gasoline in my tank (93 octane) plus octane booster just to see what happened. Well, basically my engine got pissed off at me and misfired a lot.

I'll never do that again. I am guessing I had like 98 octane in my truck.

3. ### ExhumedSelf ******.Registered Senior Member

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I heard premium does nothing for most vehicles (if not doing negative, as some aren't equipped for it). I saw some news story about some gas station getting caught selling regular gas as premium, and they only got caught because they exposed themselves--no one actually was able to tell they were not getting "premium".

5. ### one_ravenGod is a Chinese WhisperValued Senior Member

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My 86 Mustnag ran better, had more power and got better mileage with regular than with premium.

7. ### AbsaneRocket SurgeonValued Senior Member

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I went on a whole tank that was nearly clean of acetone. Result? I got 320 miles on a tank for an MPG reading of 21 mpg.

I conclude that acetone really does increase MPG... at least in my truck.

8. ### ExhumedSelf ******.Registered Senior Member

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Do you have anyway of being sure it isn't damaging engine parts?

9. ### AbsaneRocket SurgeonValued Senior Member

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Not really, but I doubt that such a low concentration is doing harm.

10. ### FacialValued Senior Member

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This is very good data. Assuming the price of gas is $3.20/gallon, and acetone$20/gal, and approximating the amount added in Absane's car is 3.2 oz/15 gallons, then with the data (the extra 50 miles) he got 7.63 miles / dollar vs. 6.67 miles / dollar. So almost an extra mile with each dollar, or a 14 % increase in distance. Excellent.

11. ### AbsaneRocket SurgeonValued Senior Member

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Too bad I am very bad about writing down exactly how much I used... as you may recall, I said I put an unknown amount in my tank...

12. ### MalibuRegistered Member

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Engine lesson

Generally speaking, 87 can be used in most cars, I'd say upto a 9:1 Compression Ratio, 91 for 9.1-11:1 and 93 in 11:1 or higher ratios, Most standard engines in consumer cars are 8-9:1 in ratio, performance heads usually increase the ratio as does a supercharger, the head by physically changing the distance from piston to head. A supercharger doesn't actually change the ratio but increases pressure in the cylinder, which is effectively the same as increasing the ratio just like Nitrous Oxide, NO and Superchargers work by packing more air, more air, more gas, more power. thats why superchargers always require 93 octane, they say using 93 in a lower compression engine is actually bad for it.

As one of the other posters mentioned, high octane can eliminate pinging, also known as detonation. Detonation is when the gas ingnites by the sheer pressure, rather than by spark, and can cause bad damage as the piston doesn't complete a full cycle like normal, adding pressure to your wrist pin, piston rod, and rod bearings. It is similar to what happens in diesel engines, but gasoline engines aren't built as thick as diesel to handle the detonation pressure. Diesel compression is usually between 17-25:1 huge difference.

My guess is that the Acetone increases atomization, thus a more complete burn, and more power, so you use less throttle than you would normally
Instead adding more air like NO or a Supercharger, it makes that burn more effcient.

13. ### cosmictravelerBe kind to yourself always.Valued Senior Member

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Here it states that its all a MYTH!!

http://www.snopes.com/autos/techno/acetone.asp

The theory, so far as I can tell, is that it enhances the vaporisation of the fuel and so reduces the fraction that is wasted by escaping unburnt out of the exhaust or past the piston rings. While I have no specific knowledge of the effect of acetone on fuel vaporisation, it is nonetheless very easy to demonstrate that it cannot give a useful benefit via this mechanism. It is very well known that the vaporisation of fuel in a modern engine under normal operating conditions is already very good, and only about 1 - 2% of the input fuel escapes unburnt. Hence, whatever the properties of acetone, it is extremely hard to see how the economy benefit can be more than this relatively small amount.

There are, of course, many people who have tried putting acetone in their tanks and reported huge benefits. But you can find equally powerful testimonial evidence for a whole raft of devices that have been scientifically proven to be worthless. Fuel consumption measured on the road is subject to so many confounding factors - traffic, journey type, driving style, weather, etc, etc - that it is very, very easy to see changes of 10%, 20% or even more, even when the true engine efficiency has not altered at all. This page considers the general risks in determining fuel consumption via uncontrolled on-road measurements rather than scientific testing. Some people have tried very hard to eliminate or compensate for the confounding factors, but in the end it is impossible to control them all outside of a proper testing laboratory.

Many "supporters" of acetone have tried it themselves with apparently good results, and are scathing of the experts (like myself) who dismiss it on theoretical grounds without doing any testing. The point is, of course, that those same experts also recognise that any on-road testing they (or anybody else) do is essentially pointless, since it is virtually impossible to separate the true effect of the acetone from the "noise factors" - therefore, why go to the time and trouble of doing testing, when it can only produce an essentially random result?

http://www.fuelsaving.info/acetone.htm

14. ### NickelodeonBannedBanned

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So Absane was bullshitting? Well thats a surprise. Not.

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16. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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One summer student job I had was as researcher for Lion Oil. Their "dynamonitor lab" only used spark plugs for 100 hours so every week-end when I drove slightly more than 100 miles home I started with "new spark plugs." There was little traffic and only one red light, at which I always stopped even if it was green. I filled the tank exactly to a scratch line I had made inside the filler tube always parking in the same spot so that was the highest point of tank. (Also always the same pump as there could be slight difference in pump measurement accuracy) Refilling after end of trip at a second gas station with the same care.

Initially I varried very minor things, like one or two windows open, radio and lights on or off (I could calculate that extra waste of energy) etc. None of my careful data made any sense, until I discovered the true variable, which was more (or at last as) important than 5 mph speed change, which I wanted to learn how important it was. (I tried to drive whole trip at constant speed - 55 or 60 mph, as I recall)*

Guess what that variable was. If I fail to return and tell some one PM me.
PS it was not "wind." - not much of that late in evening after my dinner and traffic was near zero on the trip, normally.
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*Goal of my testing was to learn if driving at 55 instead of 60 was worth while trade of time for money. (For a poor student with his first very-old car.)

Last edited by a moderator: Nov 8, 2007
17. ### cosmictravelerBe kind to yourself always.Valued Senior Member

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So you are saying Snopes is wrong as well as the researcher?

18. ### spuriousmonkeyBannedBanned

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whether you were chased by the police or not?

19. ### AbsaneRocket SurgeonValued Senior Member

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That's right.. I was bullshitting.

20. ### ExhumedSelf ******.Registered Senior Member

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The article said that reported increases in acetone must be due to some of the random factors, but we can find out after 6 months... it should of averaged out if that were the case. So can you give us an update Absane?

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He won't be able to. That stuff also damages fuel lines and they won't last a full six months. Of course if he wants to keep on replacing them...

22. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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No one has guessed, so I will tell what the relatively important varriable, MENTIONED IN POST 53, was.

Humidity and water in the air, especially if present as "micro fog droplets".

I think I understand why: There is more heat released in the cylinder when the gasoline is burned than can be efficiently used to expand the mass of burnt fuel and dry air that entered before the intake valve closed. As the piston goes down, some combustion is continuing (assume gas burns instead of explodes in "knocking") but as it nears the lowest point the pressure on it is dropping rapidly. I think the "micro drops" being converted to steam causes the fall off in presure to be more slow, effectively getting more work from the burning fuel. - Sort of "internal cooling." Most of the heat released by the fuel is dumped in the exhaust gas. (IC engine is open cycle.) Some heats the cylinder walls and ultimately leaves car via the radiator. As the temperatures in the cylinder are lower if some micro-drops are being vaporized, there is less transfer (at lower cylinder temperatures) of heat into the cooling water. Thus, the pressure curve remains higher longer as the cylinder goes down with more energy retained inside the expanding gases until the ehaust valve opens.

I am not sure the above is correct POV. I only know that when there was some obvious fog in the valleys or light rain I got better gas milage. I planned to add a "water tray" and at least a rag to wick water into the air intake stream but wrecked the car before I got around to it. (That was a blessing in disguise - as I could not afford to maintain it after the six large cans of free oil I took from the Lion Oil company were gone. It badly needed a "ring job" which was out of the question in my limited budget. I referred to the car as a "semi-diesel." Perhaps water dropplets only boost mpg when there is serious pressure loss due to "blow-by" the rings?)

Last edited by a moderator: Nov 9, 2007

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