I believe that the Arco stuff is 15 ppm, which is the target nationwide for 2007. Ultra low sulfur fuel is a win-win situation. The process used to reduce the sulfur to hydrogen sulfide gas also removes the aromatic compounds in the fuel. Aromatics have lower energy content per mass than the paraffinic molecules that remain after treatment. Thus, the centane number of the remaining fuel increases as a result. Aromatic compounds contribute to the lubricity of the fuel and there was a problem in Europe many years ago when they first started to reduce sulfur (and aromatic compounds). But the lubricity can be restored by adding back a small amount of relatively inexpensive additives such as fatty acid esters. Diesel fuels available in just about any place in the world except North America have lower sulfur and higher cetane than our diesel. Engine durability is no longer a problem. Some forms of biodiesel have almost no sulfur content and they seem to work fine.
Actually, an engine has to be tuned properly in order to take full advantage of a high cetane fuel. This is largely a matter of injection timing. Our Cummin’s are designed to run on pretty crappy fuel. So other than less noise and smoke on startup and potentially longer oil change intervals, there is not much of an advantage to running low sulfur, high cetane diesel. Except for cleaner air of course. But once the new fuel is generally available by 2007, newly designed engines will be able to realize the performance advantage.
Attention: TDR Forum Junkies 
