MPG Help

[craigsez]

Is the speedometer corrected for the larger tires?
I would change all your fluids over to synthetic oils, maybe look at a real cold air intake, check out the plugs and make sure they look good , clean the throttle body and install a catch can, ever run a good fuel injector cleaner through it ? RedLine S1 is a great Fuel injector cleaner.
keep those tires aired up to a higher air pressure.

Maybe doing those things will get you back to your 12mpg, but like was said big tires hurt gas mileage.

A cai does SQUAT,cleaning the tb might help,catch can will not do anything.....The rest of your comment "MIGHT" do something but not what most think..

 

[Midnight Storm]

T

I actually haven't used anything to recalibrate the speedometer, might have to look into that.

That would make a difference then. You are actually travelling more miles per tank than you think. If you have 35’s instead of 33’s it’s a 6% difference

 

[69GWC]

A cai does SQUAT,cleaning the tb might help,catch can will not do anything.....The rest of your comment "MIGHT" do something but not what most think..

A catch can will keep his throttle body clean, pretty simple.

But you know I was just trying to help and all and he might need all his fluids changed anyway might as well use good fluids, clean injectors cant hurt .
Also seen guys running 35psi in 35s and going up in tire pressure sure will help if he is running low pressures like that.

As far aa a CAI not doing SQUAT maybe it dont but the people making them sure insist they do.........

Also said a real cold air kit that pulls air from outside of the motor compartment not one of the hot air kits like a K/N type.


Wonder if winter fuel is doing this, not sure when they switch ?

 

[E-DAWG]

What transmission and gears do you have? Unless you have 8spd auto and at least 3.92s I would look into a gear swap. I bet a set of 4.56's would improve your trucks performance as well as its fuel economy.

I was under the impression that 3.92's used more fuel than 3:21's from all I've read but your saying increasing to 4.56's actually Decreases fuel consumption?

 

[tidefan1967]

I was under the impression that 3.92's used more fuel than 3:21's from all I've read but your saying increasing to 4.56's actually Decreases fuel consumption?

In some cases yes. It's called torque multiplication. Taller gears are fine for stock tire heights but your going to notice both a loss of power and fuel economy as you get further away especially with the 3.21's. The engine has to work harder to turn that taller tire from a dead stop therefore you will burn more gas. Since he has the 8Hp70 its not as much of a big deal since the 8spd auto has more gears and better gears in it than the 6spd auto does. That's why I asked those questions to begin with. After getting more info I too think I would start with a custom tune which will also correct the speedo making the mileage increase and make a noticeable difference in performance.

 

[RLJ10X]

Engine RPM isn't the last word in fuel economy.

3.21s may be just fine for running around empty. A lot of people drive these things like they're a car. And that's fine too. Hell, Ram 1500s come from the factory with car tires (a droopy front end, shutters, a transmission heater, thin oil, no LSD, etc) all in the name of EPA numbers. What a load of crap, but such is the world today. Pretty soon they'll all be electric.

But if you need a real truck, you get 3.92s, or better yet, 4.10s, real tires, a LSD, and get the front end out of the dirt. But the flip side is that you're going to take a hit on fuel economy. And I don't think 3.92s over 3.21s make nearly as much of a detriment as heavy tires. Just my opinion, feel free to disagree.

If you you have big tires, you need gears to match. There is no getting around physics.

As far as an accurate Odometer, even my ancient old 2011 has a GPS Speedometer and Odo via the screen on the dash. If you don't have the dash screen, any Apple phone can download a speedo and odo. You don't need to dump even more money into that pit with a custom tune, unless you just want to. But the OP started all this because he was spending too much money (on gas) .

 

[Guy lIPSKY]

Have friends that have lifted big tires and rims . Get Gas buddy cause your going to need it , if you join there club for $49 a year drops the price of your gas 20 cents per gallon for up to 40 gallons per month after that you get 5 cents off add this up its $100 per year for $49 Oh at 65 mph on my 2017 ram hemi i get 25mpg, stock

 

[slacadjuster]

Yes, my ram is lifted. Yes, I have 35x13.5" tires. But, is 8-9 mpg in the city what I should be expecting from my 2014 ram? I used to get atleast 12-14 in the city, but recently it's plummeted down to unreasonable numbers. On a full tank I'll get around 300 miles of range. Is there anything I could do to help this? Throttle recalibration? Cleaning my CAI? I mean sure I'm 21 years old and like to punch it every now and then, but ever since I've noticed this drop in mpgs, I've tamed myself to the point where I feel like I'm driving like a grandma. And, if I'm lucky I'm getting 9.5 avg mpg in the city.. I just don't get it...

Lifted AND 35" tires?? Wow, there's your issue right there. Get rid of the lift, back down to stock ride height, dump those ridiculous 35's, go back to the stock 20 size...problem solved.

In addition, if/when ya wanted to sell the truck, no one with any sense would buy that truck as it is with lift and 35's.

 

[madtrucker2016]

Well sometimes things don't work out >you play you have to pay all that big heavy stuff cost you in mileage at the pump. But it looks good right

 

[Ribtipram]

In some cases yes. It's called torque multiplication. Taller gears are fine for stock tire heights but your going to notice both a loss of power and fuel economy as you get further away especially with the 3.21's. The engine has to work harder to turn that taller tire from a dead stop therefore you will burn more gas. Since he has the 8Hp70 its not as much of a big deal since the 8spd auto has more gears and better gears in it than the 6spd auto does. That's why I asked those questions to begin with. After getting more info I too think I would start with a custom tune which will also correct the speedo making the mileage increase and make a noticeable difference in performance.

What he said. Its just like my 16 2500 6.4 gets better mpg then my 14 1500 5.7 did when towing my boat(around 6500lbs)but the 1500 smokes the 2500 on every day driving.

 

[south7west]

Lifted AND 35" tires?? Wow, there's your issue right there. Get rid of the lift, back down to stock ride height, dump those ridiculous 35's, go back to the stock 20 size...problem solved.

In addition, if/when ya wanted to sell the truck, no one with any sense would buy that truck as it is with lift and 35's.

Ram trucks come stock with 33 inch tires, at least if you have the 20 inch rims. I can't remember what size tires come on the 17 inch rims though

 

[crackerjack1957]

Ram trucks come stock with 33 inch tires, at least if you have the 20 inch rims. I can't remember what size tires come on the 17 inch rims though

275/60R20 8.9 inches 33.0 inches
265/70R17 10.4 inches 31.6 inches

http://www.offroaders.com/technical/p-metric-tire-sizes-p-metric-to-inches-conversion-chart/
https://tiresize.com/tires/BFGoodrich/All-Terrain-TA-KO2.htm

LT 35X12.50R20
121R E BSW 34.5" 12.5"

 

[kurek]

I think the problem was pretty much solved when OP said he hadn't calibrated the truck for the change in tire size, so the reported distance traveled isn't accurate.

If the truck started life with 265/70r17 (Tradesman..) then 35's travel ~11% farther per revolution so if the odometer reports 300 miles the actual distance traveled was 332 miles and instead of 9mpg he got 10mpg. Still not great of course...

It also means the transmission's guessing ~11% wrong on shift points and if the engine uses road speed in its management that's off by 11% as well which we have to assume is less than optimal for mpg.

So start with solving that problem before anything else. Programmers are $150-200 depending whose you buy, not too bad when you consider the price of gas.

Then if the fuel consumption problem persists, look for other causes. Obviously 35's and a lift behind a V8 are always going to be a recipe for poor fuel efficiency but 12 or 13mpg city should still be consistently achievable

 

[craigsez]

A catch can will keep his throttle body clean, pretty simple.

But you know I was just trying to help and all and he might need all his fluids changed anyway might as well use good fluids, clean injectors cant hurt .
Also seen guys running 35psi in 35s and going up in tire pressure sure will help if he is running low pressures like that.

As far aa a CAI not doing SQUAT maybe it dont but the people making them sure insist they do.........

Also said a real cold air kit that pulls air from outside of the motor compartment not one of the hot air kits like a K/N type.


Wonder if winter fuel is doing this, not sure when they switch ?

Yes a catch can will keep it cleaner but not increase mpg,unless it got worse before big tires were added.....Yes correct psi will help but not increase it in the sence that it will be as before previous tires...That will help and car,bike,big rig ect...

Stock air intake does come from the lower fender area and is basically the same as a store bought cai...Yes it may have a better filter (a good drop in will do the same)and a smoother flow due to a smooth pipeing vs the factory accordion type stuff....The basic theory of a cai is to add more air for intake to match with more fuel for added power which doesnt equal mpg,but it does to a degree have cooler air which again is geared twards power..

Oh yeah i get the point of trying to help but when your offering info that may not be correct for that situation,you may cause someone to go out and spend more...I wasnt intending to rain on your bbq but just pointing out a few things you may not be aware of..BUT we are all a brother hood here tryin to help where we can,nothin wrong with that..

 

[69GWC]

Yes a catch can will keep it cleaner but not increase mpg,unless it got worse before big tires were added.....Yes correct psi will help but not increase it in the sence that it will be as before previous tires...That will help and car,bike,big rig ect...

Stock air intake does come from the lower fender area and is basically the same as a store bought cai...Yes it may have a better filter (a good drop in will do the same)and a smoother flow due to a smooth pipeing vs the factory accordion type stuff....The basic theory of a cai is to add more air for intake to match with more fuel for added power which doesnt equal mpg,but it does to a degree have cooler air which again is geared twards power..

Oh yeah i get the point of trying to help but when your offering info that may not be correct for that situation,you may cause someone to go out and spend more...I wasnt intending to rain on your bbq but just pointing out a few things you may not be aware of..BUT we are all a brother hood here tryin to help where we can,nothin wrong with that..

Well .I was not giving out any bad info these things will help gas mileage if he was doing the opposite on the things I suggested like tire pressure and what not.
The catch can keeps the throttle body clean so it helps future mileage because when its oiled up its not helping ,was not trying to imply it would automatically bump his mileage up just help get it back to where it was.
And lets face it with a lift and 35s we are grasping at straws trying to get him better mileage...lol

 

[craigsez]

True but if anyone buys a 5250 lb trk with a v8 and then add fuel sucking options shouldnt be wanting honda civic mpg..

If he added a catch can now,it will only help from then on with keeping intake as clean as it is when added..Its not gonna make it cleaner as was previously....

Only things that will help todays mpg will be tire psi,maybe plugs and new filter and even maybe full synthetic oil...

To get it where it was means atleast goin back to stock sized tire size or even smaller...The rotation mass he is running will eat away at his acc and de cel,mpg,brakes...Bottom line is to go back to stock or just keep opening his wallet for added parts,tunes,gas/brakes ect..

 

[CheechDogg.0n37s]

I was getting 11 - 12 mpg 2 weeks ago ... I got AlfaOBD and changed the tire size ...now I am getting 13 -14 mpg and the truck is not guessing with shift points anymore ...I am really glad that I got AlfOBD because I also got to add LEDs and activated a few other things that the stealership would of screwed me on ...

So my advise is get AlfaOBD ...you will love it !

 

[charles Roldan]

Change your IAT Sensor and Map sensor, if that dosent do the trick, you might need a programmer or new gear ratio, higher than 3.55 maybe 4.56. Im pretty sure the sensor is shot, they never set of the computer when they do go bad, just the milage is the only hint. $50 dollar fix (iat sensor and map sensor) and only 10 mins labor. most folks go from 9.5mpg to 14-16 instantly after the fix. let me know how it went if you decide to try it. also if it works share this tip with everyone with a ram.

 

[charles Roldan]

My hemi, has full exhaust, drop in k&n filter, superchip 91, 3inch lift, and 22inch rims with 33s, city 14mpg, Hwy@75mph= 18mpg (Crusie control)