F*cking love the write-up, I thought I was the only who thought about doing this!

It truly is unique, rather than to try and squeeze every last horsepower & ft-lb possible out of the magnum V8 to instead go in the opposite direction for every possible MPG & reliability increase. With enough money, anyone can make an engine produce enough power to drop panties and bust head gaskets. But to make an engine more efficient than it came from factory, now that is truly a challenge and requires finesse. Fortunately for us, Dodge left quite a few areas that can be improved.

When I first got my Dodge, it was getting a terrible about 8.75MPG on the 5.2L Magnum engine. I started looking into all the little things that would make this a gas-sipping V8 4x4, without sacrificing reliability in the drivetrain or motor. Aside from standard maintenance, here is what I have done that has contributed to MPG increases:

Hughes Plenum Mod
Intake Kegger Mod
Port & Polish Intake Manifold
Deck Air Horns, Radius, Port, & Polish Throttle Body (TB Mod)
Double Rollercam Chain & Gears
Magnaflow High-Flow Catalytic Converter
Fresh Evap Canister
New Evap Solenoid Valve
Accel Cap & Rotor
TSB for Spark Plug Re-routing for EMI optimization
New Vacuum Lines


Soon to come:

Dual Electric Fans
Melling High Volume Oil Pump
Dana 60/70 Swap
Spyntec Hub Conversion
Iron Ram Heads
T-Case Saver

After getting these items out of the way, the truck is now getting 15.25MPG city. I am guesstimating with the dual electric fan setup & free-spin hub conversion I can pick up another 2-3MPG which is conservative. I hope I can have the 1st 20mpg+ Dodge Ram on the road.

Good luck on your build and don't let any of the naysayers change your ultimate goal of high efficiency.

 

What size tires, and what gears are you running?

 

Currently running 33" BFG & stock 3.55 gearing.

Will move to 35" & 4.10 when I find my 2500 donor axles, which certainly will take away some of the efficiency gained. If it's for bigger tires, it's worth it in my opinion.

 

With 35s your trans will love you to have atleast 4.56 !

 

I've been doing this kind of thing for decades, myself. Mainly for off-roading, at the start, but later just because torque builds are fun to drive every day. Out in the really off-road world, the parts not set aside for city people to play in, there are lots and lots of ugly steep climbs that will leave you roof braking if you try a point and smash attack. There are lots of very pretty and not often used campsites beyond them, too.

The neat thing about a torque build is that it will always give you the best overall fuel economy for the power produced. At three ton and with the coefficient of drag of a sheet of plywood I don't see a 4WD Ram bagging an average of 20MPG, but there are still some yooge increases to be had. Jumping from 14MPG to 17MPG is over 20%, which is both doable and well worth doing.

 

Any updates on this project?

 

The build has stalled the last couple months due to lack of funds (I'm a student on stipend). At the moment, I'm helping my dad rebuild the turbocharger and replace the fuel injectors in his Ford Excursion 4X4 turbo diesel -talk about a PITA! Next week, I should have garage space for my project and get around to mocking the heads and manifold up to the block to do some final port matching (not gasket matching). After that, things should start speeding up.

 

UPDATE. . .

I now have the funds to complete this project, so I have a very large order from rock auto to place in the next day or two. I realize that I probably need to replace a lot of the sensors on the truck because the truck has been sitting in the back yard for about 8 years now. I was thinking I should replace:
manifold actual pressure sensor,
intake air/charge temperature sensor,
throttle position sensor,
crankshaft position sensor, and
coolant temp sensor.
Do all these sensors actually need to be replaced, or are some probably fine? Are there any others I should replace that I didn't think of?

 

You can likely skip IAT, and ECT, I would test the TPS before replacement, crank and cam sensors though... Yeah, I would change those just on general principals. Remember to pull the crank sensor before you remove the engine, and don't install it until after the new engine is bolted up.

 

You might want a new IAC (idle air control) and maybe the O2 sensor(s)