[zonker]

i guess i should have clarified better since there are more than one type of direct injection systems being produced. It's the piezoelectric injectors thats the new technology that has allowed for very precise metering of the more refined diesel fuel.

we do have low sulfur fuel here now (and one of the reasons why diesel is now more expensive in the US than gas), but it's still a lesser grade than that used in the EU.

The low sulfur version we have allows for common rail injection systems to work, but the real impressive packages are still kept out of reach since we don't have the really good stuff.

I just found this blurb on wikipedia...

In North America, No. 2 diesel fuel is recommended, since it has a higher cetane number than No. 1 fuel, and has lower viscosity (better ability to flow) than heavier fuel oils. Some owners in North America, where cetane levels are generally poor (as low as 40), use additives, or premium diesel, to get cetane numbers closer to the standard levels found in the European market (at least 51) where the engine is designed. Improved cetane reduces emissions while improving performance, and may increase fuel economy.