5.7 hemi milage

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hextall

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Hi all
I know there are some threads out there about this but none I found were specific enough so sorry to open another! Just bought my first ram. Always been a Ford guy! I like my 14 2500 5.7 4x4 crew cab long bed quite a bit so far. This truck has 3.73 gears and it does have 285 tires on it. I know we don't buy these trucks for fuel economy but I just took a rd trip about 200 miles and the truck seems to be getting under 11 mpg. I do not have a heavy foot I did have the cruise set to 75 most of the trip the tach was sitting about 2500 rpm. If this is what it gets so be it but just seems to me awful low for even this truck. So, looking for any advice on what I can do. I worried what it will get with 10000# behind it!! Thanks in advance.
 

trx680

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5.7
i have an 06 megacab 2500 4x4 with 5.7
Its all stock
get about 10mpg according to the MPG readout
 

MADDOG

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I had an 07 MegaCab 5.7L and highway mileage rarely exceeded 13 mpg. I towed with it (9K) several times a year and it dipped to 9 unless I was fighting headwinds ...then it got worse.
 
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hextall

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Sounds like it may be normal. Anyone out there know if a programmer or a fresh air intake will help? Or any other ideas. Thanks.
 

BlkZrx

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Lot depends on terrain you drive on, mountains or flat? It's a tall, 3.5 ton truck, slowing down a bit might gain you a little too..

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stembridge

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Mine's a '15 SC LB 2500 4x4, and my best highway mileage to date has been 15.5, my calculations. I average closer to 13 or so, though.

Recently pulled a loaded 12' uhaul trailer from central GA to central IL and got about 9.5-10 or so.

es
 

MN-Ram

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Do you have a tonneau cover or topper on your truck yet? They usually help a little. Also, slowing down to 67-70mph will help. I've my truck seems to have a fuel leak above 70mph (j/k). But my mileage is a lot better under 70mph. That goes for my current 6.4L Hemi as well as my 1500 with the 5.7L Hemi.

I've never tuned a gasser, but the problem with the tuner on my old Cummins was that it was way too fun to drive. I was never light on the throttle, so I actually saw lower MPG's after the tune.

If you just got the truck, and live in a cold climate, wait for the summer gas blends. You will see a little better mileage then.
 

mtofell

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With those over-sized tires and rolling at 75MPH that sounds about right. Stop/go driving and speeds over about 65 really hurt my MPGs in a hurry with my 6.4 Hemi.
 

bobbo7915

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CTD 6.7L
Something seems off to me. On my 6.4l with 3.73 at 75mph I am only turning 1800 rpm, if I put it into 5th manually it turns 2500rpm...
 

MN-Ram

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Are you driving in T/H, by chance?
 

billa9b0ng

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I drive 67 - 70 on the highway and do a bit better. Your mileage sounds about right for driving that speed.
 

NewBlackDak

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I lose 1 mpg for every 5 mph over 65. It's a big brick, and it takes a lot of energy to push it through the air.


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hextall

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Thanks much for the replies. I was incorrect in the rpm. It's closer to 2000. I did get a little better coming home from my trip over the weekend but still only about 11.5. Again this seems normal so I'll just deal with it. Just was concerned something was wrong but it seems ok. Thanks all. Hoping I can enjoy this truck.
 

tnt2671

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2016 2500 regular cab
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Thanks much for the replies. I was incorrect in the rpm. It's closer to 2000. I did get a little better coming home from my trip over the weekend but still only about 11.5. Again this seems normal so I'll just deal with it. Just was concerned something was wrong but it seems ok. Thanks all. Hoping I can enjoy this truck.

thats about exactly what i average 11.3 to 12
 

HS-LD

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2018 2500 Power Wagon
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6.4L Hemi
What I've learned about HD MPG's so far:

62mph is the magic speed.

A Magnaflo muffler will get you +1-2 mpgs. K&N filter maybe something, CAI maybe +1.

Drive like grandma.

MPG's is worse the first 10,000 miles. It seems to get better at 500 and then at 3-4000, and then at 8-10,000. (I always wondered if the computer has a break in protocol?)

Bigger tires or a leveling kit or hauling stuff makes it go down.

No wind, 10,000+ miles, freeway with cruise at 62mph, unloaded, no traffic, flat land, 89 oct good gas, should get 16+ mpg.
 

68PowerWagon

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Do you have a tonneau cover or topper on your truck yet? They usually help a little. Also, slowing down to 67-70mph will help. I've my truck seems to have a fuel leak above 70mph (j/k). But my mileage is a lot better under 70mph. That goes for my current 6.4L Hemi as well as my 1500 with the 5.7L Hemi.

I've never tuned a gasser, but the problem with the tuner on my old Cummins was that it was way too fun to drive. I was never light on the throttle, so I actually saw lower MPG's after the tune.

If you just got the truck, and live in a cold climate, wait for the summer gas blends. You will see a little better mileage then.

Yea my 6.4 took a major nose dive when the winter blend came out. Went from about 16-17mpg to 9-10mpg.
 

NewBlackDak

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Yea my 6.4 took a major nose dive when the winter blend came out. Went from about 16-17mpg to 9-10mpg.



Mine does too. Make lots of sense. We want to reduce emissions, so we'll make them burn 30% more fuel.


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zogg

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Hemi 5.7
I had a 2013 ram 2500 4x4 with the 5.7. Around town I got about 12-13 mpg, but on the hi way it was much better. With 25,000 miles on the truck we went from Illinois to Arizona unloaded and drove between 65 and 75 mph for the whole trip. We consistently got 18-19 mpg on 87 octane.

We bought a new fifth wheel and traded for a 2016 6.4 4x4.....what a disappointment in mpg compared to the 5.7......if I get 15 hi way I'm surprised. Ugh.
 

stembridge

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Mine does too. Make lots of sense. We want to reduce emissions, so we'll make them burn 30% more fuel.


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es
 

SouthTexan

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For gasoline, it is summer blend fuels that have additives to help the environment by lowering its RVP making it less volatile at higher temperatures, not winter. Summer fuel has about a 2% higher energy content due to these additives which is one of the many reasons why you get better fuel mileage in the summer. Winter fuel does not have these additives so it has a higher RVP which increases it's volatility so it can be easily burned in colder temperatures. You would have a lot harder time starting a vehicle with summer fuel on a very cold day than you would with winter fuel. It would also run rough.

There are other things that decrease your mileage during the winter as well like lower tire pressure and the air being more dense. For every 10 F the outside air drops, your tire psi will drop about 1 psi. So if it was 35 psi at 100 F, then it is 25 psi at 0 F. Colder air is also more dense than warm air which means you have to apply more load on your engine in order to push through it. The research we did at Cummins showed a 2% increase in aerodynamic drag for every 10 F decrease in temp.

Also, for gasoline engines, colder more dense air will cause the engine to burn more fuel to stay at the optimum 14.7:1 stoichiometric air/fuel ratio. Basically 14.7 air to 1 fuel. Gasoline engines have to stay around this ratio at all times in order to run correctly and not damage the engine. Since colder air is more dense, there is more of it in a given space. Therefore the engine reads this from the MAF sensor and adds more fuel to compensate for that increased air density. If it didn't add more fuel then it will run lean which damages gasoline engines.

This is why intakes generally hurt fuel economy on newer gasoline engines since the MAF sensor will tell the ECM to add more fuel for any extra air added. This is not the case for diesels since they run lean just about all the time so intakes generally make them more efficient. Under load diesels run about 16:1 and at around 140:1 at idle.
 
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