I filled up at a local Citgo last night,& the pump read "New Premium Diesel".I couldn't find a cetane rating & the girl inside didn't know what a cetane was.When it says premium does it have to be a certain rating or can it be BS?
From what I have read, I gather that "premium diesel" is more of a proposed spec, so it can vary from vendor to vendor. Given that, cetane is not only what it provides...
The shell station that I fill up did say "premium diesel" and they covered up the "premium" part a month or so ago? Anybody know why? Winter blending? I live in oregon and diesel fuel is regulated here whereas gasoline is not...
From TechExpert on Shell Rotella Site (shell rep)...
" Compared to “rack” diesel, Premium Diesel will have better lubricity, better thermal stability, higher cetane quality, and during winter months better low temperature properties. These performance features provide the following benefits for all diesel engines – whether used in agriculture or other operations.
Today’s diesel fuels are more highly refined, and many of the natural lubricity agents are removed. Premium diesel helps assure you get optimum life from your fuel injection system. Better thermal stability protects against high temperature degradation that can occur with modern fuel systems where fuel is used to transfer heat from the injection system. This degradation can lead to fuel system deposits and shorter fuel storage life.
Improved cetane quality can contribute to less smoke on start up, faster cold weather starts, a quieter engine, and improved combustion (more power, better fuel consumption, and reduced emissions). And better low temperature properties means more protection from fuel gelling and consequently fuel flow at much lower temperatures."
The one problem with the proposed "premium" spec is that it only has to meet 4 of the 5 'premium' specifics. i.e. it may have improved lubricity and 3 other parameters, may yet be old 40 cetane diesel.
All in all, the new "Premium" spec is pretty loosey goosey and does not address contaminants whatsoever other than meet the original fed spec of .05% dirt and water... Which is horrendous..
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