Question: what is the difference between tier 4 interim and tier 4 final?
Answer: Q. What is the difference between Tier 4 Interim/EU Stage IIIB/Japan MLIT Step 4 and Tier 4 Final/Stage IV standards? A. Tier 4 Final/Stage IV standards for engines 130-560 bkW (175-750 bhp) will require an additional 80 percent reduction in NOx emissions from Tier 4 Interim/Stage IIIB levels.