can i get better mpg with my 2004 2500?

have a 2004 2500 5,7 auto quad cab short box with 140000kms-
truck is stock except for tires are one step bigger than stock(285s i think)
has flowtech shorty headers
vararam ram air intake
dual 2.5 inch exhaust with no cats( front sensors are installed and hooked up but rear ones are tied up under the truck still plugged in)
just replaced the plugs with autolite xps
superchips vivid programmed on fuel mileage setting with stock trans shifting program( using the superchips trans shift program causes late shifting and freewheeling in the trans on coasting -no engine braking in 1st)


i got 12.5 u.s. mpg(18.82liters per 100 k) on a strictly highway 110km 70mph 1000km road trip using gps odometer and liters used-

although it has way more power than stock it seems to have gotten worse on fuel econmy since i bought it. i was hoping i'd see at least 15 us mpg, my 500 horse srt 10 ram gets 17 us mpg
what else can i do? before i head home i'm goin to set the programmer on the 87 octane tune and see what happens

Could be alot of things honestly. First I would change out your spark plugs for the stock copper plugs because that's what the 5.7 likes best. Then if it were me I would put my cats back on. Finally I would set my tuner to performance.

The only way to improve mileage on any vehicle is by:

1) Improve combustion (ie sparkplugs and ignition parts). The stock setup is pretty good so I don't think a lot of improvements are going to be netted when changing anything out in that system.

2) Improve air flow. This reduces back pressure which increases efficiency. You have already done a cai, exhaust, and headers, so not much more improvement can be found there. Also clean the therottle body if you haven't already done so.

3) Reduce aero drag and weight. Simple answers here, get the vehicle as low to the ground as practical, tonneu cover and remove everything out of the vehicle that is not needed.

4) And finally, reduce drivetrain loss. This has been the Ram's biggest weakness. For mostly highway driving get higher gears in the diffs. For better city mileage get lower gears in the diffs. Also changing all the fluids in the vehicle to synthetic will help. I've been reading that aftermarket torque converters are a lot more efficient then the stock one. Get that replaced too.

Also lowering un-sprung mass is going to help a lot. Get the lightest wheels and tires possible. I would also put that tuner on performance, and keep your foot off of the gas peddle as much as possible.

So it's stock except for headers, programmer, exhaust w/no cats and bigger tires. Gotcha!

Most people see a loss of mpg on the fuel saver setting vs.the performance setting. If i use the performance tune I see a 1-1.5 mpg increase over the fuel saver tune.

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Time for a Prius!!!!!!!!!!!!!!!!!!!!!!!!

might have to start driving my old 78 ford again it got 15.5 mpg lol

My 2004 HD Hemi would get around 12mpg in town and 14mpg or so on on the highway. Other than a CAI and an exhaust my truck was stock in the engine performance department. I think 35" tires and 3.73 gears on the highway actually helped my fuel economy. I'll be honest, for a HD Hemi I think you are pretty much on par for fuel economy.

Originally Posted by 04Ram2500Hemi

My 2004 HD Hemi would get around 12mpg in town and 14mpg or so on on the highway. Other than a CAI and an exhaust my truck was stock in the engine performance department. I think 35" tires and 3.73 gears on the highway actually helped my fuel economy. I'll be honest, for a HD Hemi I think you are pretty much on par for fuel economy.

Amen! It's a Truck!

free spin hubs,might help some(not much,but some)....

I think I get 14 mpg ish(city/hwy)

set the programmer on the 87 octane tune- came home, at the first fill up it took 88 liters to 485kms= 13 us mpg or 18.1 l/100k
i have to fill up again it the morning, i went 550 or so kms and still have1/4 tank.

and dont buy a superchips vivid programmer piece of junk keeps loosing communication with my archos unit and it makes the low fuel dinger go off and flashes the air bag light on . i was ready to toss it out the window

I'm getting 8-9 mpg city in my 2006,2500 wow this truck drinks like a sailor on a weekend pass.Still would not trade it for anything

you can see my set up in my sig
mpg ranges from 10-12 city, 11-14 hwy

whatever you might try to gain mpgs will be massively expensive in comparison to the gains you see (meaning, you're going to spend more on parts/mods than you would if you just kept filling up under your current conditions)

your tires are the only things that will get you a noticeable gain
but the 2500's look ridiculous with 265's

I chased MPG when I got my first '06 Hemi Ram. Put on hard tonneau, SuperChips, CAI, and 4.56 gears. Mostly no change, pay for the fuel or sell the truck, IMHO.