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Note: While this sketch is not based on quantitative values, it is intended to show the relationship between brake specific fuel consumption and torque. As pointed out in the columns text, there is a specific relationship between peak torque and minimum b.s.f.c. In fact, some dyno engine tuners minimize wear on an engine in test by first determining peak torque b.s.f.c, and then working to achieve that level of b.s.f.c. elsewhere int he rpm range. Generally, below peak torque, there are insufficient flow rates to achieve maximum volumetric efficiency. Above peak torque, there is insufficient time to maintain the desired mean flow rate.