Need help with Gas Mileage...

Hello I' am the owner operator of a 2005 Mack granite tri axle dump. It has a AI-375 engine with an allison 6spd auto. This truck drinks diesel like theres no tommorow. I work with a broker in my area primarily and get paid by the load so I really can't be soft on the pedal but I don't abuse the pedal to much. I really just do the speed limit but the speed limit in my area is 70mph on many of the big highways. Also the distances im driving are are about 110-15miles round trip for 1 load. So im in the process of getting aluminum wheels all around for the truck maybe an aluminum bed but thats years down the road and I need help now. I have recently been looking at maybe a propane injection system when I noticed a Hydrogen Fuel Injection system made in canada. But I don't know to much about the HFI system to justify if its worth the cost. So does anybody out there have any other suggestions that might help me out....

 

lol, this is the second time someone has busted my chops about saying gas and not diesel. Sry when I was writing up the post it just flew write over my head but honestly you guys know what I mean.