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  • karjunkie 06/30/09 3:09 pm PST

    The EVs are vehicle emissions standards in the State of California, but have gained popularity because they're easy to use. Here's what the different standards refer to:

    Low Emission Vehicle (LEV): This is the average vehicle, the minimum that you can legally drive in California.

    Ultra Low Emission Vehicle (ULEV): ULEVs are described as 50% cleaner than the average new vehicle for the model year.

    Super Ultra Low Emission Vehicle (SULEV): SULEVs are 90% cleaner than the average new vehicle for the model year.

    The 328i SULEV uses the N51 versus the N52 engine. In order to comply with SULEV requirements, the N51 is a variant of the N52 engine. Some of the SULEV measures for the N51 include:
    • Near engine catalyst with additional underbody catalyst
    • Secondary air system
    • Optimized combustion chamber geometry in cylinder head
    • Modified piston crown for lower compression
    • Plastic valve cover with integrated crankcase vent valve and separator (from N52KP)
    • Stainless steel fuel lines with threaded connections
    • Radiator with “Prem-air” coating
    • Throttle system - EGAS08 carried over from N52KP
    • Airbox with Activated carbon filter for EVAP control
    • Purge system pipes are made from “optimized” plastic

    BMW claims there is no performance difference other than the increase in weight which adds about 30 lbs.

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