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Old 11-09-2012, 06:21 AM
Pierre Louis Pierre Louis is offline
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Originally Posted by BMWTurboDzl View Post
No place to install an after market fuel filter. Personally with what you said in terms of roads and more importantly fuel quality I would avoid the 335d. For reference it uses the Bosch CP3 injection system or so I've read.

Sent from my MB525 using Bimmer App
Ultra Low Sulfur Diesel (ULSD) is now required even in rural Alaska since 2010. The required standard is ASTM D 975 which also has better fuel cleanliness:

ASTM D 975 limits the ash content of most diesel fuels to a maximum of 100 ppm.
(Inorganic particles and oil-soluble, metallo-organic compounds both contribute to the
ash content; but, only inorganic particles will cause wear.) The U.S. government has a
tighter specification of 10 mg/L (approximately 12 ppm) for all particulate matter. However,
neither specification addresses particle size. While most fuel filters recommended by engine
manufacturers have a nominal pore size of 10 microns,6 studies by the Southwest Research
Institute reveal that the critical particle size for initiating significant abrasive wear in rotary
injection fuel pumps and in high-pressure fuel injection systems is from six to seven microns.
6 1 micron = 1 micrometer = 10-6 meter
However, as engine designs to reduce emissions result in higher fuel rail and injector pressures,
the tighter clearances will have less tolerance for solids and impurities in the fuel.
Consequently, some engine manufacturers are now specifying filters with pore size as low
as two microns.
If you think he needs a secondary fuel filter for Alaska, then we all do, since all US on-road diesel fuel has the same maximum particulate contaminant percentages now since 2010. Unless our friend is using off-road diesel, this should not cause a problem with his fuel pump.

Unless of course you think unacceptable wear occurs from winter diesel having higher kerosene content, which I imagine would be more common in Alaska even during "Summer" months. The ASTM standard is specific for lubricity also, so it should not be as bad as before ULSD.

ULSD has improved fuel consistency and cleanliness. This is why the US can now export it in the international market, as it is acceptable for other countries' standards, and why its price is higher than gasoline, which Europe exports to us.

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