Fuel additives - Page 2 - PeachParts Mercedes-Benz Forum

Hatterasguy · #16 05-08-2008, 12:17 AM

I have been running diesel straight from the pump, with maybe a splash of Power Service here or there...as recommended by Mercedes...so far 21 years and 270k miles and it seems to be working pretty well!

probear · #17 05-08-2008, 12:32 AM

Quote:

Originally Posted by aklim

I thought that the quietness of the engine is because of the change of combustion characteristics and not the lubricating properties? I agree that it has better lubricating properties than D2. Whether it is significant when it comes to longer life is not proven. IOW, nobody knows what the graph of lubricity vs wear looks like. What is the point of diminishing returns? Again nobody knows.

Poke here for one study on BioDiesel and wear tests. I have seen other studies, but plain logic dictates that better lubrication equals less wear.....Notice that this report also includes LSD, which from what I've read has better lubrication qualities that ULSD.

The irony of the lower BTU is that BioDiesel has a higher oxygen content which actually boosts performance under low RPM and higher engine load conditions.

The article goes on to explain numerous points, one of which is, and I quote:
"Good performance in fuel combustion with Biodiesel and its blends resulted in a smooth running engine."

Granted, this article is about marine engines, but last time I checked, 'engines' did not really know where they were installed.

rcounts · #18 05-08-2008, 02:12 AM

I use bio - B5 or higher concentration on a regular basis. When I can't get bio, I've always added Power Service at the 1:400 ratio recommended on the bottle - 1 oz per every 3 gallons of $2 diesel. I buy it at Wally World too and the last 96 oz jug I bought was $15.20 - so it costs about a nickle a gallon to treat your fuel at the 1:400 ratio.

Though I may be switching to 2-stroke oil - the lubricity chart in another recent thread on the subject shows it to be a better lubricant - though I need to do a bit more research into what concentration is required to get the benefits shown on the chart and what the relative cost is.

The thing about bio is that it has slightly lower BTU value (~130k/gallon vs. ~140k/gallon for #2), BUT it has a higher cetane value (~50 vs. ~40 for #2). A lot of people find that the benefits of the higher cetane value offsets the lower BTU value. Especially in blends.

For example; with B20, 20% of it is bio with 130k BTU/gallon and 80% is #2 with 140k BTU/gallon. So the blend has roughly 138k BTU/gallon. With 80% #2 at a cetane value of 40 and 20% bio with a cetane value of 50, the approximate cetane value for B20 is 42. So you're only losing 1.5% of the BTUs but gaining 5% in cetane value. Bottom line, most people seem to find that their mileage is about the same on #2 and B20.

For B5 the numbers are a .1% drop in BTU value and a .5% increase in cetane value - an even less significant difference. BUT the bio triples the lubricity of the fuel - even at concentrations as low as B5

LUVMBDiesels · #19 05-08-2008, 07:30 AM

The study done for the Engine Eanufactures Association showed that even 2% biodiesel was much better at lubricating then LSD or ULSD #2 or any other additive. However, I can't get a regular supply of BioD down here in WBGV

I use Lucas Fuel Treatment as it was shown in that study to have better lubricating properties than Diesel Kleen. I still use DK to bring up the cetane level, but it has much less effect on the 603 than it had on the 617. The 603 just runs so much quiter and smoother than the 617 ever did.

#20 05-08-2008, 08:27 AM

Quote:

Originally Posted by aklim

I thought that the quietness of the engine is because of the change of combustion characteristics and not the lubricating properties? I agree that it has better lubricating properties than D2. Whether it is significant when it comes to longer life is not proven. IOW, nobody knows what the graph of lubricity vs wear looks like. What is the point of diminishing returns? Again nobody knows.

I agree completely, the "smoother running" is due to the combustion rate of the fuel and has nothing to do with lubricity. I would probably run B5 if it was actually available someplace on this planet and priced the same as dino-diesel. Until you can actually find it at the typical highway exit, it's an academic discussion. Other "additives" are probably harmless, use them if they make you feel better.

rcounts · #21 05-08-2008, 11:25 AM

Quote:

Originally Posted by Craig

I agree completely, the "smoother running" is due to the combustion rate of the fuel and has nothing to do with lubricity. I would probably run B5 if it was actually available someplace on this planet and priced the same as dino-diesel. Until you can actually find it at the typical highway exit, it's an academic discussion. Other "additives" are probably harmless, use them if they make you feel better.

True, its availability isn't quite "there" yet, but one thing you can do - if you can find somewhere selling B100 - is start carrying your own 5-gallon can of "fuel additive" in your trunk. Even a half a gallon of B100 in a full tank of fuel will get you a little above the 2% level...

aklim · #22 05-08-2008, 11:32 AM

Quote:

Originally Posted by probear

Poke here for one study on BioDiesel and wear tests. I have seen other studies, but plain logic dictates that better lubrication equals less wear.....Notice that this report also includes LSD, which from what I've read has better lubrication qualities that ULSD.

Granted, this article is about marine engines, but last time I checked, 'engines' did not really know where they were installed.

Yes, that is what I have problems with. Those tests allude to the "more is better" attitude. The question is, up to what point? At what point will lubricity not matter. IOW, if you can apply a treatment to make your door last 500 years but the house itself falls apart at 100, does the extra 400 years mater.
I would love to see some real life studies which show that at regular ULSD levels, the engine lasts 100K. With 520 microns wear, it lasts 85K, at 460, it lasts 95K, etc, etc. I'd like to see real time data that explains to me, as you go down the lubricity values, the mileage decreases up to what point and at a certain point, more lubricity doesn't help in real life.

Dumb engines.

#23 05-08-2008, 11:55 AM

Quote:

Originally Posted by rcounts

True, its availability isn't quite "there" yet, but one thing you can do - if you can find somewhere selling B100 - is start carrying your own 5-gallon can of "fuel additive" in your trunk. Even a half a gallon of B100 in a full tank of fuel will get you a little above the 2% level...

That's simply not worth the trouble. Last week I drove about 3000 miles from CO to NC and back, that's about 8-10 fill-ups along the way. I'm not about to start playing around with blending fuel or additives when I'm going someplace. If/when I can stop at a random station on I-70 and buy B5 put of the pump I will use it, until them I'm using straight ULSD. If my next IP lasts 250K miles, instead of 300K miles, I'll just have to replace it sooner; big deal.

aklim · #24 05-08-2008, 12:12 PM

Quote:

Originally Posted by Craig

If my next IP lasts 250K miles, instead of 300K miles, I'll just have to replace it sooner; big deal.

But that is just it. Nobody really knows what happens in the real world. If the IP lasts 50K more by lowering the HFFR score by X, then we can calculate what it costs vs what you gain. I wouldn't want to spend $5000 to save $3000 worth of engine wear.

Hatterasguy · #25 05-08-2008, 02:13 PM

Its not really worth worrying about that stuff. There is no way to know for sure how long an IP will last. You can do everything perferctly, run B5 and some imperfection can cause it to fail at 150k miles.

More so when you take into account that you can write these cars off each year to the tune of .505 cents a mile!

With the money your saving with the tax write off a few repairs here and there are nothing.

rcounts · #26 05-08-2008, 02:26 PM

Quote:

Originally Posted by Hatterasguy

More so when you take into account that you can write these cars off each year to the tune of .505 cents a mile!

With the money your saving with the tax write off a few repairs here and there are nothing.

I assume you are talking about the mileage tax deduction when driving for business purposes? That's cool that you're in a position to get to do that. My company goes one better and actually reimburses me at that same rate for work related travel miles.

BUT, I'm sure there are a lot of people who don't have that benefit. Unless you are talking about some other tax deduction tha we can all take advantage of.

Please clarify.

Hatterasguy · #27 05-08-2008, 02:38 PM

Nope thats what I'm talking about.

It sucks if you can't take advantage of it, last year was the first year I could deduct my mileage.

#28 05-08-2008, 03:14 PM

Quote:

Originally Posted by Hatterasguy

Nope thats what I'm talking about.

It sucks if you can't take advantage of it, last year was the first year I could deduct my mileage.

A very good reason not to work for other people.

But it does look like I'm going to be ordering an engine from metric pretty soon, I think I have a broken ring but I haven't gotten it in for a compression test yet. That should put a little dent in this years mileage allowance.

#29 05-08-2008, 03:17 PM

Quote:

Originally Posted by aklim

But that is just it. Nobody really knows what happens in the real world. If the IP lasts 50K more by lowering the HFFR score by X, then we can calculate what it costs vs what you gain. I wouldn't want to spend $5000 to save $3000 worth of engine wear.

You're correct, it's basically a crap shoot with high mileage engines. You will never be able to correlate the cause and effect anyway. If you want a guarantee, write a check for $60K and drive a new car.

aklim · #30 05-08-2008, 03:25 PM

Quote:

Originally Posted by Craig

You're correct, it's basically a crap shoot with high mileage engines. You will never be able to correlate the cause and effect anyway. If you want a guarantee, write a check for $60K and drive a new car.

Even with new engines, how would you prove it besides running a bunch of them with different levels of lubricity in the fuel? If you do the test diligently, you might be able to draw a graph of lubricity vs component wear. That way we know how much lubricity we really need. Without knowing the point of diminishing returns, how do you calculate how much lubricity you need to have?