Over Drive
I have always wondered if I put an overdrive unit on my RV will do any good. If it gives you a 10% decrease in RMPs does it give you 10% better gas mileage? Or just 2 or 3% better MPGs. Would it be wo...
Forum Discussion
going to the forum for your engine... find out the rpm other owners of that engine gets for mileage considering the various loads.
my 6.7 cummins got it's best millage at 1950 rpm. which put me over the speed limit in oregon... so when towing i would drop a gear or two when climbing passes. maintaining that sweet spot. regardless of road speed. as long as i wasn't over the limit or the limit of the trailer tires (most trailer service tires are rated at 65 mph max).. the 5.9 cummins sweet spot is around 1800 rpm. so some research for that sweet spot will determine what gear ratio you should have in your final drive, considering transmission having an overdrive or not..
with the 8.1 vortex on flat land you could drop below the sweet spot, but if you get into a head wind. you would need to change gears to keep the load off the engine and to bring the rpm up..
my 6.7 cummins got it's best millage at 1950 rpm. which put me over the speed limit in oregon... so when towing i would drop a gear or two when climbing passes. maintaining that sweet spot. regardless of road speed. as long as i wasn't over the limit or the limit of the trailer tires (most trailer service tires are rated at 65 mph max).. the 5.9 cummins sweet spot is around 1800 rpm. so some research for that sweet spot will determine what gear ratio you should have in your final drive, considering transmission having an overdrive or not..
with the 8.1 vortex on flat land you could drop below the sweet spot, but if you get into a head wind. you would need to change gears to keep the load off the engine and to bring the rpm up..
