Posted by Vaughn [99.14.81.6] on Tuesday, December 16, 2014 at 20:29:05 :
In Reply to: 4BT mileage update. posted by Sterling [99.98.76.231] on Tuesday, December 16, 2014 at 19:40:21 :
You may be under geared at 2200 @ 75mph and turning those big tires is a lot of weight to spin. All of it is a lot to ask of a 4bt. I'm assuming 2500 is cruising rpm for the 4bt and getting that around 60-65 should improve your mileage. If your using a 5 speed O/D tranny, try a trip in 4th, that s/b 1 to 1 gearing, keep the engine at cruising rpm, and see what mileage you get. That will determine if the truck might need to be re-geared. Doesn't mean you need to re-gear if 4th places you at a comfortable speed, but to improve mileage, you may need to cruise at a slower speed in 5th.