Well, I'm driving a a full 1-ton B2500 with 3.92 rear, 12-passenger Ram Van with the Magnum 5.2L. It likes fuel.
I've done a few things to get it from 11mpg to 14mpg with more items to work on to improve this more. One buddy of mine has a similar Ram Van and has hit 20mpg with it already. Here's a few things he's done already.
- Copper/brass cap-n-rotor
- Run with the next load rating tires that can inflate up to 65-80psi
- Repack the wheel bearings with low viscosity synthetic grease for both the inner and outer bearings. The best I've found is from the tractor supply stores that is also high temp and has a sky blue color.
- Clean the IAC and the IAC ports on the TB
- Get a higher flowing exhaust and higher flowing CAT
- Use synthetic 75W90 in the rear. Chrysler has a TSB that mentions this improvement for the trucks and mpg increase.
- Replace O2 sensors if they are over 80K. Avoid the bosch since those don't work well with the Magnum engines nor the ECM/PCM
- Go with an eFan like the Viper V10 or Taurus setup. The Viper is nearly a drop in place setup since the original Viper engine was a Magnum.
- Seafoam the TB intake.
- Never run injector cleaners with alcohol in your tank.
- Adjust the rear brake self adjusters from dragging. This is a big loss of mpg for trucks.
- Clean or replace the PVC
- Clean the crank case breather
- Use the 195 T-stat. Yes, this helps with mpg. Using the 180 burns more fuel, but gives more power.
[b]2001 Dodge Ram Van B2500 Magnum 5.2L, 3.92, RoadMaster MKII-XXF[/b]
[b]2005 Dodge Caravan 3.8L SXT SnG[/b]