06 hemi 13ish mpg 16-17 highway unless there's a lot of hills

 

06 short bed 5.7 with tonneau cover
BBK shortys Magna-flow hi flos and Magnaflow dido muffler
Diablosport tuner on 93 tune
Helix throttle body spacer
K-N CAI
2 inch drop shackles
275-50-20's
3.92 axle
Electric fan

I drive 75 miles daily to and from work, mostly interstate driving Average 15-16 mpg manually calculated@ 75-85 mph. Ive found on my truck that the computer always reads about 1mpg better than the truck is actually getting

 

If you didn't change gear ratios when you put on those oversize tires, that explains your poor mileage. Moving those big tires with out the torque multiplication of lower gears, will work your truck to death, thus the poor mileage

 

I think you meant WITH '' the tourque mutliplication of the LOWER grears.

Higher gears would make for more torque on the lower end making them easier too turn, however it would also increase your rpm's at higher speeds......killing your mpg's, regardless. bigger tires are a mpg killer.

I have 3.92's as well, with 35's with an avg. of 15 mpg, But I bay her and actually strive for the mds too kick in.

 

nah, old man was right with the way he said it.... meaning having taller gears multiplies your torque making it easier to turn bigger tires. the truck in question is currently lacking that. also, increasing your rpms at higher speeds with bigger tires would bring it closer to stock rpms considering what size tires he went with

 

thank you

 

IT'S JUST LIKE IF YOU GET THE 20" TIRES FROM THE FACTORY, THEY COME WITH 3.92 AXLE, AND IF YOU GET 17" WHEELS, THEY COME WITH 3.55s iF YOU TRIED TO RUN THE 20" WITH 3.55 GEARS, IT WOULD RESULT IN POOR MILEAGE, AND LACK OF POWER

 

you're welcome lol

 

ive got a 99 ram 1500 4x4 with a 5.2 with 271,000 kms and gets an embarassing 8 mpg city right now. bout to do a rebuild on it and hope for more after matching the intake gaskets to the heads and intake and mathing the exhaust gaskets as well

 

I average about 18 mpg on the autobahn as long as my foot is out of the happy pedal. Of course that is setting cruise at 65 mph too...