I hate to ask this, but-IF higher ocane fuel is more resisant to ignition/combustion//whatever, (and we all know that it is), will adding a proper amount of diesel to gasoline raise the mixtures' resistance to ignition/combution/whatever, since diesel is harder to ignite. I know there are no free lunches in the Laws of Nature, (i.e. no perpetual motion machines allowed), so what are the trade-offs, aside from the obvious of using too much diesel and not being able to start the engine?
Not saying that it's right to do... but my dad used to put a small amount of diesel in his car to raise the octane... said that kept the car from "dieseling" when he shut it off. That was back in the early 70's.... Big no-no with modern cars because of injection, O2 sensors, Cat. Converters, etc... I think he said 1/2 gallon or so to a full tank. Kamp
Gas is rated by octane as a measure of resistance to compression ignition... Diesel is rated by cetane as a measure of its willingness to cook off under pressure...
There was a situation a few years back where aviation gas got accidentally tainted with a small percentage of jet-a, which is basically diesel. The end result was some severely damaged engines. I think I would be careful of mixing things that could have unknown results.
The octane rating of diesel is generally 15 to 25 Two different measurement systems. Instead of heptane and iso-octane they use napthalene (cetane rating = 0) and n-cetane (cetane rating = 100). In total opposite to octane ratings, the higher the cetane rating the higher the fuel's propensity to knock! It's important to remember there is no fuel in the cylinder on a diesel during compression.....like a gas motor You can burn it mixed with gas, because I've done it before in an old pickup.......we were out road hunting deer one night and ran my truck out of gas. I had diesel in a 50 gal tank in the bed with a transfer pump......so I used some of that to get home.....in a drunken stuper , of course.
I once filled a low-compression Chey Nova about 90 diesel/10 gas... we New Joisey people don't know how to pump our own gas, see. Late night interstate rest area, hundred miles from home... I gave it a very brief test...steady knock, enough smoke to ensure immediate arrest. You are't talking 90%, but still, it is not an anti knock... I can't say how I got home until I research certain Federal statutes of limitation...
Diesel fuel is highly refined fuel oil. Remember any oil in the combustion chamber will CAUSE detonation of the fuel. Once the flame front is lit and moves to the outside of the combustion chamber the pressure in the cylinder quickly goes to astronomical proportions.Pressure plus heat will cause the remaining low octane or oil laced fuel to instantly detonate. Then the two flame fronts converge and ...well for lack of a better term seriously abuse the pistons,rings,headgaskets etc. That sudden hammer like detonation will kill an engine. Remember Octane rating is a fuels resistance to detonation,we want a smooth controlled burn,not instant uncontrolled detonation in a gasoline engine. The S.A.E. had a 16mm film I watched in high school about combustion,I wish I could get ahold of it now.They had a single cylinder flathead engine with a clear cylinder head on it and used high speed photography to demonstrate normal and different types of abnormal combustion. It was truly a fascinating film. ALL hotrodders should get a chance to view this movie as it clears up any and all questions.Is anyone here a member of S.A.E.? Do a little research for us and find this old film! PLEEEZEE
It's the exact opposite of what you want to do. In grad school if we couldn't afford low-octane reference fuels we'd just mix in a little diesel -- knocked like crazy.
I have read numerous articles on adding 4 oz of pure Acetone to 20 gals of gas and getting 7-8 mpg increase. I haven't done it because I can't find PURE Acetone,,it always has a second chemical in it,, but I did meet a guy that has been doing it in his diesel Mercedes for 20 years and swears by it. He buys his at a beauty supply store,,I just keep forgetting to stop by and get some. My work truck ( 04-F150 4x4-5.7L) gets about 11mpg pulling a trailer I'd LOVE to get a little better mileage, I spend between $200-350 per week on fuel !!
Acetone again? Hasn't that been beat to death? On Myth Busters they put moth balls in a fuel tank running a big 500" Caddy and it ran hard (on a test stand). Don't recall what it did but some kind of chemical reaction to boost power. I wouldn't do it however...
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