Additives ( a discussion)

[deniseO30]

Has anyone EVER seen, felt, or proven that an additive has worked as advertised?
Such as;

Diesel Fuel Additives by STP® | Diesel Fuel Injector Treatment

Please do include biocides, cetane boosters and synthetic oils in your discussion.

My only experience was watching a family member use stp (the thick stuff) to slow down the leaky seal and the engine did smoke less. (in the 60s this was)

I used Starbrite Diesel additive and found out how bad the fuel system was on my boat about 3 yrs ago. Since then, she has a new tank, pump, and lines. and lots of spare elements for the primary racor 220 with R-24T (10 microns) element, and Nappa gold for the secondary, The engine is a universal 5416 (Z751 kubota)

Looking forward to interesting discussion!

[RichH]

IN my neck of the woods Stanadyne are the favored products.

Additives will help 'boosting the Cetane rating' of the fuel
... if your engine is 'old' it was designed for diesel fuel that had much higher cetane (think octane in gasoline) rating than present ... higher cetane, slower fuel burn and less 'knocking' under load.

... Lubricity -- older engines depended on the sulphur (now almost totally removed from #2 diesel) to lubricate the high pressure injection pump. Have you priced a new or rebuilt high pressure injection pump lately?

... emulsifier to break up water into 'teeny' or macromolecular size ... prevents injector tip erosion.

... biocide - you already have bought the T shirt on that one. No discussion needed other than keep the MINIMUM amount of fuel on board + some reserve (dont always fill the tank ... it has a relatively short 'shelf life' when exposed to atmosphere), buy FRESH fuel from a high volume truck stop.

for an older engine .... definitely use additives unless you are lucky enough get your fuel from a non-USA source.

[jrd22]

Yep, what Rich said. Our local water taxi company started using Stanadyne and their injector rebuild interval went from 1500 hours to 3000 in the older model Volvos they run.
I use it and also a biocide in the sailboat (the fuel in the power boat doesn't stay in there long enough to worry about), mainly because I'm afraid not to, not because I really know that it helps that much:-))

[Minnewaska]

How about Marvel Mystery Oil in the diesel fuel. No idea if it helps, but understand that it adds some sulphur back and cleans things out.

p.s. I'm a biocide and stabilizer user. The new stuff I bought this year has cetane booster as well. Sorry, Denise, I know those are off topic.

[sea_hunter]

Being year-round boaters we use Stanidyne products onboard and in our vehicles because their products work.

[deniseO30]

I was expecting just the opposite reaction guys! I must say after my starbrite additive experience I've been reluctant to use any thing in the diesel on my boat. The stuff may have been why the porous bottom of the old fuel tank started leaking faster too!

[dabnis]

Many years ago I used This:

Power Service Products, diesel fuel additives, prevent gelling, clean injectors, disperse water, boost cetane, reduce emissions, improve fuel economyPower Service Products, diesel fuel additives, prevent gelling, clean injectors, disperse water, boos

in VW turbo and non-turbo automotuve diesels with no fuel system problems. Not affiliated with Power Service.

Paul T

[hellosailor]

denise-
If you search on gasoline, that simple fuel is a witches' brew of about 60 chemicals. I expect diesel is less complicated--but there's still plenty of room for the refineries to brew up each batch, each brand, differently. Stuff that would give it better longevity is a waste of money in road fuel, which is usually targeted at a 60-90 day life.
So, some extra bucks for extra ingredients? Yeah, there's something to that. The folks who get religious about adding biocide (usually after a fuel failure and a thorough cleanout) usually don't have that problem again.
I've used Stabilant in a gasoline engine laid up for a year--and it hummed. Whether these things are all overpriced is a whole other question, some of them are 99% base stock and damned little else, you've got to wonder what the "else" really should sell for.

But if you burn your fuel quickly, and have no problems, and your filters aren't pulling out lots of critters...good clean fuel might be all you need.

[CarelessNavigator]

Originally Posted by RichH

Additives will help 'boosting the Cetane rating' of the fuel
... if your engine is 'old' it was designed for diesel fuel that had much higher cetane (think octane in gasoline) rating than present ... higher cetane, slower fuel burn and less 'knocking' under load.

I think you need to go back and re read what you have written. Octane and Cetane are diametrically opposed as far as what they do inside the combustion chamber.

From Wikipedia;Cetane number or CN is a measure of a fuel's ignition delay; the time period between the start of injection and the first identifiable pressure increase during combustion of the fuel. In a particular diesel engine, higher cetane fuels will have shorter ignition delay periods than lower cetane fuels. The higher the Cetane number the more easily the fuel will combust in a compression setting (such as a diesel engine).

[pdqaltair]

Originally Posted by deniseO30

I was expecting just the opposite reaction guys! I must say after my starbrite additive experience I've been reluctant to use any thing in the diesel on my boat. The stuff may have been why the porous bottom of the old fuel tank started leaking faster too!

Many additives, such as Starbrite, often function as biocides, not by design, but simply because the solvents are toxic to the bacteria. Even a fuel source change can do this. If the tank is infected or sludged, any change in solvency can set things off.

Porous? It's done, guy. That's code for it's been corroded through.