Originally posted by HC
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. For my truck, wind resistance is the key, and seems to overshadow the minor efficiency gains the Cummins engine shows in "lab" charts at the preferred 1900 rpm.
I agree wind makes a big difference. mine seems to be best in the 1900 to 2000 rpm range but a good strong head wind will kill my mileage. Drop it from 20 highway to 17 highway. But a good strong tail wind will pop it up a couple of mpg. Maybe we need sails on these things
