Answer to:
What is the average MPG for a semi tractor? a class 8 highway tractor will vary depending on it brand of engine. caterpillar averages 6.5 to 7.5 cummins averages 7 to 8 detroit averages 7 to 9 and mercedes benz engine averages 9 to 12. some of the mercedes engine have turbos the will spool up to 50 000 rpm. that amazing for a turbocharger of that size. hope his helps you... from David

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