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Gas Mileage on my new 2500 is bad

22K views 12 replies 10 participants last post by  Taylo1 
#1 ·
I have a 2012 Ram 2500 with 5.7 Hemi, the mileage is 11 in the city and 14 on highway driving conservatively. Anyone with any tried and true methods of increasing the mileage by either changing the exhaust, chipping or adding a cold air intake. And, which of any worked the best and with what products?
 
G
#2 ·
Intake and exhaust will help a little. Unfortunately, there are no programmers available for your year truck yet. CJD encrypted the PCM software and no one has, as far as I've read, cracked the code yet.

I have an AFE Stage 1 intake, a Magnaflow single in / dual out 18" muffler and a DiabloSport Predator programmer. The combination of those modifications netted me almost 4 MPH HWY and just a little above 2 MPG City.

Also, it's been reported by the truck and the LX/LY Hemi powered car communities that with some mileage on the engine, MPG improves.

But a good start for you would be an intake and exhaust. As far as intakes go, don't get a cheapie off of eBay. The inlet tubes are thin-walled cheap plastic, they crack and the filters are junk. Some have even been reported to have come apart and filter material was sucked down into the engine. Not good.

There's a thread under the Modification Sections on the 5.7L HEMI intakes that are available. Cooler air creates a better, more efficient combustion cycle. That's because cooler air contains more oxygen molecules. One of our members, who is now full-time rv'ing it but still posts here, did a great job with comparing some of the intakes available.

Good luck!
 
#6 ·
I've got about 1k miles on my 2012 2500 Hemi. With 360lbs of sand in the back I'm getting about 12.1 to and from work (secondary roads, rolling hills) and 18.5 on the freeway. In my experience nothing effects your gas mileage like your right foot...except maybe too much idling.
 
#7 ·
Your mpg is about average from what I have read on some other forums. I average about 14hwy & 12 city in my PW. I've got 4:56 gear ratio 33" tires. Isn't much difference with 4:10 gears, the 3:73 gears are gonna get you a little better mpg. I only have 1500 miles on my truck so everything is still pretty tight. I'm sure once things loosen up I might see a slight increase. All in all I think the mpg is pretty good for a truck this size.
 
#11 · (Edited)
I am gonna bring the thread back to life.. I now have a 2012 2500 with the Hemi and the mileage is not good about the same as everyone else. My questions is I replaced my wheels and tires with 325/60/18 from 245/70/17, how big of a mileage buster is going to that size of tire going to be. I have 4:10 gears and with the 17's running 70 RPM's were 2100 with 18's they are running 1800, you would figure lower RPM's better mileage. I may put the donuts back on...
 
#12 ·
I really want a new Hemi powered 2500 and am currently researching them. The plan is for a small lift and 35's. I will share a couple things from my experience with lifts and large tires. First, a lot of people freak out when they first figure their MPG's after adding taller tires. But they fail to realize that their figures are off if they didn't reprogram the computer so the speedometer/odometer is accurate. Also, at any given size an all terrian tire will usually give slightly better gas milage than a mud terrian. Also, tire/wheel weight and tread width will also affect milage/performance. A 325/60-18 is basically a 33x13.00 tire. A slightly narrower 33 inch tire (like a 285/65-18 or 305/60-18) will help your milage a little.
 
#13 ·
I really want a new Hemi powered 2500 and am currently researching them. The plan is for a small lift and 35's. I will share a couple things from my experience with lifts and large tires. First, a lot of people freak out when they first figure their MPG's after adding taller tires. But they fail to realize that their figures are off if they didn't reprogram the computer so the speedometer/odometer is accurate. Also, at any given size an all terrian tire will usually give slightly better gas milage than a mud terrian. Also, tire/wheel weight and tread width will also affect milage/performance. A 325/60-18 is basically a 33x13.00 tire. A slightly narrower 33 inch tire (like a 285/65-18 or 305/60-18) will help your milage a little.
I love my 2500, I traded my 2011 1500 in because I did not like the bed length and I tow a 4 door jeep. I am even thinking of going down to a 285/60/18 which is a 31.5 tire. I am running the Nitto terra grapler.
 
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