Bio Diesel & 4-108

[never monday]

Originally Posted by john540

...... and I've heard anecdotal evidence of better MPG on it.

That would go against the laws of physics and possibly thermodynamics too.

B100 has less BTU's per gallon then Dino diesel.

[john540]

Originally Posted by never monday

That would go against the laws of physics and possibly thermodynamics too.

B100 has less BTU's per gallon then Dino diesel.

Yeah, well, I never studied law.

But seriously, I read that Petroleum diesel contains 12% more energy by weight, but only 8% more energy by volume due to the increased density of biodiesel, so it would stand to reason that you could expect an eight percent decrease in mpg by switching to bio, however, I have heard anecdotal evidence all over the board, some of them pretty extreme. I can't verify any of them, but I met I guy who swore that his big pickup went from ten mpg with petro to fifteen with bio. Maybe he was mistaken, maybe he needed a tuneup, maybe his engine converted more of the energy from the bio to hp, I don't know. I've never touched the stuff, but I'd like to be able to make my own fuel just in case fuel was unavailable. Personally, I think an engine that ran on ethanol would be nice, because you could use the fuel for other uses if you got thirsty.

[hellosailor]

john, considering that "bd" is about as specific a term as "metal"...there's no contradiction in one brand of it having more or less power than another. And given that bd doesn't have all the addiitives that pump diesel has, even more difference between the two of them. Factor in that the extra "cleaning" power of bd might also be affecting injector nozzles that needed a cleaning, and I doubt you'd have to break any laws of physics (which more and more appear to be very local laws anyhow) to see differences in economy when switching from one fuel to another. Heck, car owners see differences in performance and power when switching from one brand of gasoline to the next, why should diesel be any different?

[thinwater]

The infamous "diesel algae"; bacteria and fungus in actuality.

There are a number of studies suggesting that the differences are minor; those I have seen were sponsored by the bio-diesel industry. I have been culturing bugs in both ULSD and b-20 as part of a research project, and I can tell you the differences are quite measurable - b-20 decomposes several times as fast, though the reasons have not been identified and I will not venture a guess at this time.

[pbutler]

I've got a 1986 Westerbeke 27 in my Nonsuch 30, and over the last few years I've used biodiesel in various concentrations from zero to 100%. Here's what I've found:

First, let's make sure we're talking about the same thing. There are a number of folks here who seem to confuse biodiesel and straight vegetable oil (SVO). SVO is just what it sounds like: used (or new, but rarely) vegetable oil. It has a very high viscosity and almost always requires installation of a pre-heater in the fuel line to prevent gelling. I'm guessing this isn't what you're talking about.

Biodiesel is transersterified vegetable oil. It is much closer in viscosity to petrodiesel and can be burned in an unmodified diesel engine. There are a number of biodiesel distrubutors througout the United States. I'm assuming this is what you're talking about.

I've found that mainly the issues you face using biodiesel in a sailboat auxillary are exactly the same issues you face using petrodiesel: filters and water. Depending on where you live, availability might also be an issue.

When I started using biodiesel I replaced my fuel lines and changed all my filters. All that stuff is/was 20 years old and needed replacing anyway. The only place left with natural rubber is in the lift pump, and I haven't had any problems. If it quits, I'll get a new one and it'll come with viton seals.

I did notice increased crap in the primary (racor 500) when I started using biodiesel, but not much. Probably this is because my tank is pretty clean and the lines were new. It certainly never got to be enough to cause a problem.

The main problem I've found is using a mix of bio-d and petro-d seems to result in some white spooge in the bottom of the filter bowl. I'm not sure what this stuff is, but it's much worse in winter, so I think it might be some sort of water/glycerine/petrolium byproduct. Either that, or the algae is a different color (and there's a lot more of it). I don't get it in summer at all. I also don't get it when I run either straight biodiesel or straight petrodiesel. At any rate, it's a pretty slow accumulation, and cleaning the bowl when changing the filter (twice a year) keeps it from becoming a problem.

The only real measurable benefit I've noticed to using biodiesel is less soot in the exhaust. Because of the location of the factory exhaust on a Nonsuch, they're notorious for having an exhaust stain on the transom. Running a biodiesel mix has greatly reduced this for me. Obviously, the smell is also much nicer. Claims about increased lubricity leading to longer life don't really apply to our engines, since sailboat auxillaries tend to fail from causes other than wearing out their bearings, cams, rings, etc.

I haven't noticed any operational differences between using petrodiesel, biodiesel, or a blend. The temp is the same, RPMs are the same, and it starts fine on either.

I hear an awful lot of apocryphal information about biodiesel, but very little of it is based on first-hand experience. My experience has been that very few of these concerns are warranted.

Hope that helps.

[Chief Engineer]

Very Nice post

[Therapy]

Originally Posted by pbutler

First, let's make sure we're talking about the same thing. There are a number of folks here who seem to confuse biodiesel and straight vegetable oil (SVO). SVO is just what it sounds like: used (or new, but rarely) vegetable oil. It has a very high viscosity and almost always requires installation of a pre-heater in the fuel line to prevent gelling. I'm guessing this isn't what you're talking about.

Biodiesel is transersterified vegetable oil. It is much closer in viscosity to petrodiesel and can be burned in an unmodified diesel engine. There are a number of biodiesel distrubutors througout the United States. I'm assuming this is what you're talking about.


.

Thank you for that.

I was going to scream the difference soon.

Since this is a sailing forum and diesels are a fact of life for almost every one I assumed that some had actually looked into what this stuff is but I am wrong on that. There are, after all, forums like this one that are easily accessed.

But then they have some of the same answers like keel vs deck stepped masts.