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Old 01-15-2022, 10:44 PM   #41
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Originally Posted by StarChaser View Post
ofer,


Octane is the explosive value of fuel. Typically Gasoline has 87 (or More) Diesel fuel has about 10 Octane. So Gasoline has about 8.7 times the amount of explosive power of Diesel. Don't do it, it isn't just bad for your engines, they can literally explode like having a grenade go off in each one of your cylinders (with the accompanying shrapnel).



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Just an FYI. This is all wrong.


This is from Wikipedia.

Quote:
In North America, gas stations offer two types of diesel fuel — according to ASTM D975[5] these are named No. 1 and No. 2 fuel. No. 1 fuel (kerosene) has a natural CFPP of -40 °C but it is more expensive than No. 2 fuel. Adding No. 1 fuel will lower the CFPP of No. 2 fuel – adding 10% will lower the CFPP temperature by about 5 degrees.[6]

For some diesel motors it is also possible to add even lighter fuels like gasoline to extend the CFPP characteristics. Some car makers were recommending adding up to 20% gasoline to permit operation in cold weather (at the price of higher consumption) and it had been common practice in Europe where No. 1 fuel is not offered at gas stations. Since the 1990s car makers began selling only direct injection diesel engines — these will not withstand any gasoline portions in the fuel as the high pressure in the injection device will not withstand any loss of lubrication from fuel oil without doing damage to the injectors. High pressure fuel pumps depend on diesel fuel for lubrication and the addition of gasoline will cause adverse wear and eventual failure of the pump.

Car makers selling Common Rail or Unit Injector diesel engines prohibit the dilution of diesel fuel with either gasoline or kerosene as it may destroy the injection device
In an extreme emergency when the long term or near term health of the engine is a secondary consideration I would bet that you could run 25% gas if you could add some additional lubricity and could premix (just an opinion based on anecdotes). But that would depend on circumstances. Do you need to make it 500 miles? 50 miles? Could you risk the loss of the engine or injector pump to completely strand you between here and there? It would seem the higher the ratio of gas you trade off nearly equal proportion of reliability to the point of at some ratio not being able to run at all. So how would that affect your "emergency". In addition adding 25% of gasoline will not result in "stretching" your fuel supply by 25%. Gas has less energy density by volume than diesel of something like 15%. So diluting with 25% of gas might stretch your range only some fraction of that 25% if your scenario was volume limited.

In running through possible scenarios of why one might do this ....It would be a very odd circumstance that this would make any sense at all.
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Old 01-16-2022, 07:09 AM   #42
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"I have an aux tank with 100 gal of gasoline.
If I dump it into my diesel tank what would happen?"

Many euro diesel autos use 10% gas added to diesel fuel to make the car easier to start in the cold.VW sez its fine.

I would not go over 10%..

ATF as diesel fuel is fine , it is common in repair shops to fill fuel filters , as its clean , and doesn't present a problem.
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Old 01-16-2022, 07:43 AM   #43
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What are the options if any on adding gas to diesel to make a few more miles.

any percentage mix that are acceptable and or addling ATF or something like that to the mix.
I see I'm not the first to respond but, DO NOT DO THIS!!!

Call your towing company and ask them to bring you more fuel. Better yet, don't run short in the first place. Plan ahead.
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Old 01-16-2022, 11:00 AM   #44
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If I was looking to extended the range of my boat, and I had a 100 gallon gasoline tank, I would absolutely run it mostly empty and fill it with diesel fuel. When switching it back to gasoline I would pump the diesel completely out, throw 5-10 gallons of gasoline in it to clean it out and either throw it out or pump that directly into my diesel fuel tank to get rid of the junk mixture than fill the gasoline tank back up with gasoline.
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Old 01-16-2022, 12:12 PM   #45
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Raise the combustion temps, coke the injectors, reduce lubricity. What could possibly go wrong.
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Old 01-16-2022, 12:39 PM   #46
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Round and round we go.

Perhaps the OP can proceed with the test and settle the matter once and for all.
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Old 01-16-2022, 12:52 PM   #47
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Round and round we go.

Perhaps the OP can proceed with the test and settle the matter once and for all.
good idea thanks
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Old 01-16-2022, 12:55 PM   #48
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Round and round we go.

Perhaps the OP can proceed with the test and settle the matter once and for all.
And he missed your sarcasm.
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Old 01-16-2022, 01:01 PM   #49
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And he missed your sarcasm.
actually you missed mine
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Old 01-16-2022, 01:23 PM   #50
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Actually... Sarcasm has no place and means little when fooling with potential life or death high combustion fuel-in-tanks, then high ignition fuel-inside-engine mixtures.
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Old 01-16-2022, 02:56 PM   #51
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Not to mention the destruction it does to your wallet..>>>Dan
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Old 01-16-2022, 03:14 PM   #52
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Raise the combustion temps, coke the injectors, reduce lubricity. What could possibly go wrong.
Wrong direction, gasoline will cool combustion temps, diesel is the more energy rich fuel. Cutting it with a less dense fuel will cool combustion temps. Coke the injectors??? Never heard of that before, you thinking wet stacking maybe? Now you are right that it reduce lubricity but all of the multifuel engines add oil to the mixture to add lubricity and I would as well if I was using gasoline/ diesel mixture. None of it is as good as straight diesel
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Old 01-16-2022, 03:22 PM   #53
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In college in 1975 (MS State U) I bought a used 1971 Mercedes 220D. With three friends we went out West to Tetons and Yellowstone. Got to Denver and thought we were about there - ha. Thought it would be cool to drive through the mountains vs the interstates. Two lane roads, and we were soon low on diesel - stopped at an old service station - they had no diesel, and none was around. Saw a kerosine tank - took on ten gallons of kerosine and added two gallons of gasoline. Ran like a top.
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Old 01-16-2022, 03:22 PM   #54
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Not the same
Why but use a 5gal can or a bladder for more fuel?
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Old 01-16-2022, 03:58 PM   #55
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In college in 1975 (MS State U) I bought a used 1971 Mercedes 220D. With three friends we went out West to Tetons and Yellowstone. Got to Denver and thought we were about there - ha. Thought it would be cool to drive through the mountains vs the interstates. Two lane roads, and we were soon low on diesel - stopped and an old service station - they had no diesel, and none was around. Saw a kerosine tank - took on ten gallons of kerosine and added two gallons of gasoline. Ran like a top.
we are now at the 80% 20% tested. we are getting somewhere.
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Old 01-16-2022, 04:12 PM   #56
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I, too, do NOT recommend what the PO has described. However, some of the posts seem a little inaccurate in the terminology, so I would like to try to clear this up. If there is any error in the following, please let me know.

FLASH POINT
The flash point of a volatile material is the lowest temperature needed to evaporate enough fluid to form a combustible concentration of gas.
Diesel: 52C (126F)
Gasoline: - 43C (- 45F)

AUTOIGNITION TEMPERATURE
The autoignition temperature of a substance is the lowest temperature in which it spontaneously ignites in a normal atmosphere without an external source of ignition, such as a flame or spark.
Diesel: 210C (410F)
Gasoline: 247-280C (477-536F)

OCTANE NUMBER
An octane number is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating.
In a typical spark-ignition engine, the air-fuel mixture is heated as a result of being compressed and is then ignited by the spark plug. This burning normally takes place via rapid propagation of a flame front through the mixture, but if the unburnt portion of the fuel in the combustion chamber is heated (or compressed) too much, pockets of unburnt fuel may self-ignite (detonate) before the main flame front reaches them. Shockwaves produced by detonation can cause much higher pressures than engine components are designed for, and can cause a "knocking" or "pinging" sound. Knocking can cause major engine damage if severe.
As a general guide, higher octane gasoline has a higher autoignition temperature.

COMMENTS:
As you can see, you could throw a lighted match into a bucket of diesel fuel at room temperature and it would not light. By contrast, gasoline is so volatile (evaporates readily) that it can be lit at any temperature likely to be encountered.

Interestingly, the autoignition temperature of diesel is some 100F lower than that of gasoline. However, fuel in the bilge is unlikely to get raised to high enough temperature to autoignite. If it does start on fire it will have been the result of a spark and any spark has a temperature far in excess of these autoignition temperatures.

I worked overseas for many years and in Brazil in the 80s there was a shortage of diesel fuel and it was being delivered with up to 15% gasoline content for a period. This did not seem to damage the diesel engines, but made boating much more hazardous because its flash point was below ambient temperature.

Regards,
Nick
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Old 01-16-2022, 04:24 PM   #57
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As you can see, you could throw a lighted match into a bucket of diesel fuel at room temperature and it would not light. By contrast, gasoline is so volatile (evaporates readily) that it can be lit at any temperature likely to be encountered.

Nick,

Absolutely correct. We were doing crew qualifying and they had to extinguish a fire. The fire chief had a pan of water with some diesel floating on the water. He tried with a lighter to ignite the diesel, no go. Then he tried a road flare, no go. I told him to add half an ounce of gas to it, he said no that was too dangerous. After trying everything he could think of to ignite the diesel he finally added a small bit of gas. Then we threw a lighted match at it and it went right up.
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Old 01-16-2022, 04:36 PM   #58
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At the mix suggested, I would guess the engine won't last long.
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Old 01-16-2022, 05:45 PM   #59
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Goodness, goodness folks. This ain't war time. Mixing different types of fuel is dangerous on more than one level and not necessary except in the most strained conditions. Just keep enough of the correct fuel aboard.
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Old 01-16-2022, 07:04 PM   #60
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As you can see, you could throw a lighted match into a bucket of diesel fuel at room temperature and it would not light. By contrast, gasoline is so volatile (evaporates readily) that it can be lit at any temperature likely to be encountered.
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this is true for any gasoline boat. i get it. it has nothing to do with the mixing factor.
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