WMO Black Diesel - Cetane Number

[Revesz Metal]

Hi all,
Anyone making black diesel? WMO. I've just started driving around on it myself in my 1984 mercedes 300D.
Got to thinking about how this stuff works and possible pitfalls in using it.
One obvious fact that hasn't been addressed after you filter and blend to desired viscosity is the Cetane Number.
So for all those making WMO work for them, we don't care that the cetane value is nearly zero?

I'm going to blend in a little biodiesel if and when I can find it. Also dump a few pennies worth of cetane booster in per liter of fuel.
Just curious what others have to think about cetane, autoignition, compression engines. That whole topic seems to not come up much in black diesel discussions.

 

[Jesus Freak]

I do WMO, but I'm not scientific about it. Look up a company "PA Biodiesel" and they might can point you correctly. And there's a guy that pops on here every now and then @AcIdBuRn02ZTS that has a YouTube channel and he's pretty scientific. There's also @Mt_Man thread about pushing his centerfuge limits, which is pretty scientific. That's the best direction that I can point you.

 

[kbenz]

never really thought much about any of that. I just run it through the fuge and add some rug to it. couldn't even tell you what percentages I use honestly

 

[Jesus Freak]

never really thought much about any of that. I just run it through the fuge and add some rug to it. couldn't even tell you what percentages I use honestly

Now yer talkin'.....get er dun and down the road.

 

[ut99dot1]

probably higher (better than normal diesel) https://www.sciencedirect.com/science/article/pii/S2352484718300362

1) The long carbon chain components in the lubricating oil increases the cetane number of the mixed fuel

 

[Mt_Man]

I would be careful blending wmo with wvo specifically, but also cautious with biodiesel could form a precipitate that settles out, think it is like a lacquer, and when heated(engine and friction) will glue ip and injectors solid.

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. Jeff has some good videos.

I think most people don't worry to much about cetane. The biggest takeaway I had was gas is scaled on octane, diesel is cetane. So to much gas can retard the autoignition characteristics of the blend. Are you single tanking or dual tanking? If single tanking I suggest listening and feeling what the engine is telling you. How does it start? How does the heater work? How does the turbo sound? normal? too fast/too slow? How is the throttle response? The biggest thing to preventing coking is probable how easily the blend burns. That can be improved by heating the oil/blend or blending to a diesel viscosity. Some heating of diesel probably would not hurt. Note the gasoline boils around 80f so to much heating with gas blends has the potential to create gas bubbles in the fuel lines. I test oil I am questioning flammability by dipping a piece of paper towel in and try to lite it. Paper towel is like a wick. Monitor for how easy it burns, flame color, smoke color/soot level, and ash residue.

Interesting look at google search for cetane for different fuels. They don't list gas as having a cetane number. I wonder if it has a negative value or just 0. wasn't able to find anything.


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The cetane number of a fuel measures how quickly it ignites. The scale for measuring cetane numbers ranges from 0 to 100, with higher numbers indicating faster ignition.

Diesel

• Regular diesel: Has a cetane number of around 48
• Premium diesel: Has a cetane number of around 55
• Biodiesel (B100): Has a cetane number of around 55
• Biodiesel blend (B20): Has a cetane number of around 50
• Synthetic diesel: Has a cetane number of around 55

Kerosene

• Kerosene has a cetane number of around 49

Natural gas

• "Gas-to-liquid" diesel made from natural gas or methane gas can have a cetane number of 75 to 80

Biodiesel from vegetable oil

• Has a cetane number range of 46 to 52
• Biodiesel from animal fat has a cetane number range of 56 to 60
• Dimethyl ether has a cetane number range of 55 to 60

A higher cetane number means that fuel ignites more easily and completely, which can improve fuel efficiency and reduce emissions.

https://web.archive.org/web/20090202155114/http://fuelmagic.net/Cetane Booster.html
going down a rabbit hole now haha