[FC] Alcoholic Corvairs?

[Rad Davis]

This is true if and only if you have varnish buildup in your fuel system.

Acetone has an OK octane rating, though nothing exceptional.  It is very 
volatile.  It's also an excellent solvent.  If you have a grungy fuel 
system and you add acetone to the fuel it will dissolve the grunge.  This 
is theoretically a good thing, but there is the minor problem that all the 
grunge (rust held in place by varnish, in my case) floats into the fuel 
filters, plugs them, and then the engine stops running.

If you want a good commonly-available octane booster, look for toluene.  It 
has an acceptable volatility and a good octane number (RON=121).  It also 
has no oxygen in the molecule, which makes it a better fuel (more energy 
density) than Acetone.

If the fuel system is in good tune, I can't imagine why acetone would 
improve fuel economy.  It has a low yield of energy and a high 
volatility.  For that matter, adding *any* octane booster is not usually 
going to improve your fuel economy.  Octane rating is related only to knock 
resistance.  If your engine is set to design specifications and isn't 
knocking under load on the unmodified fuel, then changing to a higher 
octane number won't help anything, and might hurt, as many octane boosters 
are oxygenate compounds with lower energy densities than the gasoline to 
which they're added.

It's true that you can get some additional fuel economy if the pump fuel 
you're using isn't up to design specs on the engine (say on a 140 or 180 HP 
corvair when you can't get fuel above 87 PON and it pings on 87) then 
spiking the fuel will allow you to run stock specs for ignition timing and 
compression ratio.

So the short answer is that adding acetone doesn't magically do anything, 
unless there's something wrong with your engine beforehand.  Save your money.

Fuel chemistry has been pretty well documented over the last 100+ 
years.  Trust me,  if there were a way to magically increase fuel economy 
by x percent by dumping a little industrial waste in the fuel tank, the 
auto manufacturers would have jumped at it decades ago.

--Rad Davis
(former vehicle emissions chemist)
'65 Greenbrier Deluxe #968





At 08:34 AM 4/29/2005 -0700, you wrote:
>I've heard that adding an oz of pure acetone for every five gallons of gas 
>raises your octane level more purely than does buying premium fuel. 
>Supposed to get you up to 20% more power and milage.   Has anyone else 
>tried this or even heard this?
>Mike
>----- Original Message ----- From: <CorvairEd at aol.com>
>To: <corvanatics at corvair.org>
>Sent: Thursday, April 28, 2005 10:35 PM
>Subject: Re: [FC] Alcoholic Corvairs?
>
>
>>krupross at sunwave.net writes:
>>Hey CE.... how much does methyl alcohol cost these days?
>>Any difference between methyl and ethyl alcohol?
>>thanx
>>Merv Krull
>>
>>Merv,
>>Methyl alcohol costs about the same as gasoline right now and gets less mpg.
>>Not a good choice for economy.  But if you want raw power and a clean running
>>engine it may be your thing.  If gasoline goes much higher in the future it
>>could become the fuel of choice.  Ethyl alcohol has less power in it than
>>methyl but costs less so could be an even exchange economy wise.  The 
>>price of both
>>forms of alcohol would cost less if they were to be made with serious mass
>>production.  In order for alcohol to produce maximum power in an engine the
>>compression must be raised to at least 14 to 1 or better yet 16 to 1.
>>
>>Ed Corson (CORSA member)
>>Inland Empire Corvair Club
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>
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