I've been looking as MSDS for those things on and off for some time, and also in the past few days. Guess I tend to geek out on projects...
There seem to be three significant classes of ingredients in them all:
Solvents. which for most mean some form of naptha (stoddard solvent, white spirits, coleman fuel, lighter fluid, etc). If they're not winter additives, they use the heavier distillates which are more like mineral oil and contribute more to lubricity, rather than reduce it.
Detergents/dispersants/surficants (Soap): Where you see things (e.g. Stanadyne, AMSOil, etc) like trimethylbensenes, xylols, cumene, ethyl benzenes, and friends. You also see these in insecticides performing the same function, btw.
Cetane improvers: The two biggies are 2EHN and Octi-something (Amsoil). Fuels vary widely in 'sensitivity' (effectiveness) to these additives, depending upon the stock and how much as already been added by the supply chain.
The solvents/detergents are what helps you with gel-point lowering in cold weather - keeping waxes in solution, and help "clean" the injectors also... Cetane improvers help with cold starts.
If all you want is to protect your pumps, as the study shows, a gallon of biodiesel (or a modest container of wesson oil) does more than all of them.
Mark
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UFO wrote:
After seeing this lubricity study, I would think one should always use a lubricity additive. BTW, 2% biodiesel ranked best by a factor of 2 over nearly everything else, and some appear to make lubricity WORSE. The national standard for ULSD is 520, and I understand that Stanadyne and other pump manufacturers would prefer something on the order of 400 for longer pump life.