Quote:
Originally Posted by Pierre Louis
Many believe, after looking at the data, that CBU is a regional issue. This would imply that the base stock, which often comes from one or two refineries to all brands, may be at fault, or at least something else such as climate or driving style for each region.
Each brand of fuel, however, uses its own additive package and has its own terminals, although its not uncommon to get fuel from a different brand's terminal when its economically feasible.
I got the word straight from an engineer at Marathon (last month) that they use, at least in their gasoline, STP additive. He also verified that additives are put in at the terminal, not at the refinery. If you search through the ASTM/SAE literature, additives in diesel are not thought to be good while transporting through the pipeline or at the refinery. It apparently mixes with other types of fuel that use the pipeline and is not otherwise economically feasible.
I have no idea if brand name fuel is necessarily better than "off-brand" but can only use inductive reasoning to say that BMW, as a reputable company, would not put anything but brand name, top-tier fuel in their test vehicles.
PL
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Very interesting. Thanks for sharing. I just did some more research on diesel and was wondering if it had to do with cetane rating or the composition of biodiesel (B5 vs B100 or pure petrodiesel), but your reply suggests that the additives are the dominant contributing factor here in CBU. I'll do some more research on STP additives myself. Again, thanks for sharing your knowledge!
FYI, some other diesel heads have shared that Chevron will have 49 cetane rating. Some regions with Chevron's Diesel Techron reportedly have 51.
The next best bet, at least in the west coast, is ConocoPhilips (76), which offers 47 cetane rating.
These numbers were provided by corporate employees, apparently.