Sucky Fuel Mileage

[Lsfarm]

Milage improving

E7Mack96, you might be able to improve your milage by changing to synthetic differential lube. In the cold temps the thicker lube does eat some fuel. Especially with two differentials.



Check your tire pressures, and pay attention the to the prevailing wind. Drop your speed when pushing a significant headwind or draft an 18-wheeler when you can.



And try an Edge Ez, the increased fuel timing results in better fuel milage.



As far as the 12v vs 24v, my '96 4x4 3. 54 Lwb, auto, ext. cab never exceeded 20 mpg, no matter how I drove it. And it was a pig compared to any of the following four 24v trucks I've had. All were stock except my current truck.



Hope this helps, Greg L

 

[Steve Roseman]

Originally posted by WyoJim

I had a 12 valve 5 speed that got 22mpg at 70 on the highway. A regular cab that weighed 5800lbs.

I now have a 24V Auto Quad Cab that weighs 6700 lbs and gets 21 mpg at 65 mph. And it will run over my old 12 valve. Smoke that illflem.

Just had to get in on this one, can't let the overvalved boys get away too easy

So Jim, hows that 24 going to run over the 12 when it's going 65 and the 12 is going 70?

 

[nascar]

I'm at 20mpg highway (about 73mph on cruise) and 15mpg city in the summer. Winter is 1. 5mpg lower on truck listed below (stock). Truck weighs in empty at 7100#. 4300# up front and 2800# in rear with a full tank of fuel and no load.

 

[THancock]

I drive 50 miles a day and always have the Cruise set at 65 w/3. 55s. My best after 11000 miles has been 17. 8. I average about 17. 0. Frankly, for such a small engine I figured I'd have gotten better. The bright side is it's better than any gas motor and has the pulling power too.

 

[jjohn]

80 miles a day Hiway

2002 QC SB 3. 54 auto (2800 miles on it today) always use Stanadyne = 19 MPG @ 75 - 80 MPH.



My 90 did better w/ gear vender O/D and 3. 08 ratio, auto = 20. 5 to 23 MPG. @ 75-80 MPH.



I am hoping after 10k Miles or so MPG will go up... but It doesn't sound likely from other posts.

 

[CharlieMiller]

I fail to see what the beef is I personally think the mileage is great for a 3500 4x4. My mileage is about the same and its not a 4x4 but I don't have that many miles on it yet.

 

[nascar]

No beef on my post. I'm thrilled to have a 7100#, not very aerodynamic, pickup that is capable of 20mpg.

 

[HTRDHLR]

I have 2000 miles on my 3500 QC 4x4 and I am getting 13. 5 in the city and I am actually happy with that (even though I would like more). I went ffrom a 2500 gasser that I could never get better than 11 mpg I figure when it gets broken in and we get into summer it will get better

 

[StakeMan]

17. 6 city with a load in the bed

22 highway empty but pulling 2 CO passes



see sig.

 

[ReggieRam]

Sounds pretty normal to me

For driving a big heavy truck with training wheels like I have, getting 18 MPG is actually pretty decent. I always sell my wife on my mods saying that I'll get better mileage and actually save money in the long run. I can say that I added maybe . 5 MPG when I added the K&N, and maybe another 1-1. 5 highway when I added the the PE Comp (but I completely negate that by hotrodding around town!). The best thing I ever did for my mileage was put a cap on the bed. That maybe bought me another 2 MPG's all around, but at the cost of it I figure it'll take me about 200,000 miles to pay it off! So now I regularly see right around 18 MPG on the highway at 75 MPH, but that's with a 4x4 3500 with 4. 10's. I have no complaints whatsoever with that since my old ford gasser never got anywhere near that. Rickson claims that their 19. 5" rims will add 1-2 MPG to your ride. I have no idea, but I am considering them just because they look cool and then I can add some bigger tires to my truck. My wife says that people will start wondering if I have a small ****** if my truck gets any bigger, but what the heck.

 

[Mark_Kendrick]

Reggie. . Let em wonder.

Big trucks are

Mine got 16-17 hwy b4 the Comp. . Since . . too early to tell.



Highest 18. 9 -driving 60 all hwy

lowest 9 - Haulin A$$ weighing 21k



Usually 15-16 mixed driving 15-17 hwy depending on speed.



My 7800# truck gets better mileage than most 1/2T trucks. Not as good as Dad's PSD but hes has to drive a Phord

 

[RKohn]

check my sig...

 

['956Wheel]

Remember

Just try to remember why the govt. was so nice to add those extra, un-needed valves... . as you "run over" the 12 valvers:{



Mike

 

[zimman20]

wish I could.....

Wish I could get better than 14-15 MPG, I have the 3500 with the Auto. Supposedly no longer using winterized (oxygenated) fuel in NJ so that shouldn't be the issue, plus that mileage is consistent in the year since I've had it.



However, I know I need to get around to checking tightness on clamps, intake bolts, et al to make sure I'm not losing mpg on loose bolts/clamps, I'll get to it soon! Hope to see better power with everything tightened down as well.....



Oh, and can't forget to check/clean the IAT..... (so much to do, so little time!)



zman

 

[CCahill]

Way Sucky

I've got 33K on my truck..... first 30K, I was getting 16. 5-19..... Now for some unexplainable reason, I've dropped to 13-13. 5..... No changes in fuel, or driving habits..... Goin' in on Wed for a new transfer pump... . although I fail to see how that could effect my mileage...

I'll keep ya posted. .



:{



Colin

 

[Joe Mc]

Re: Sounds pretty normal to me

Originally posted by ReggieRam

I always sell my wife on my mods saying that I'll get better mileage and actually save money in the long run. I can say that I added maybe . 5 MPG when I added the K&N, and maybe another 1-1. 5 highway when I added the the PE Comp (but I completely negate that by hotrodding around town!). My wife says that people will start wondering if I have a small ****** if my truck gets any bigger, but what the heck.

I'll have to remember than when I start to bomb and as far as the small ****** who cares what other people think we know it ain't the size of the pen it's how you write your name - besides if they are talking about you/your truck they are just jealous

 

[Joe Mc]

Re: wish I could.....

Originally posted by zimman20

However, I know I need to get around to checking tightness on clamps, intake bolts, et al to make sure I'm not losing mpg on loose bolts/clamps, I'll get to it soon! Hope to see better power with everything tightened down as well.....



Oh, and can't forget to check/clean the IAT..... (so much to do, so little time!)



zman

ZMAN has a good point - tightness and cleanlyness is next to - well you know the rest. Do the tighten up now!

 

[Turbo Thom]

Well on mine, before the 370 injectors I was getten right at 21. Now with "all that power" I'm at a consistent 17 mpg at 75, I went 3 tanks with the cruise control on 76, and got a little over 15. The milage at 75 is town and highway. The 370's may be comming out. I can't drive 60 where I live. To many yankee transplants to run you over.



. . Preston. .

 

[HC]

I know some experience better mileage in the 2000 rpm sweet spot. I know Cummins charts show more efficient operation at 1900 for the 24V.



Lightly loaded, my truck gets better mpg at 1500 rpm than 1625, better at 1625 than at 1750, better at 1750 than 1875, better at 1875 than 2000, and drops way off above 2000. I've got over 75k worth of "calculated by hand" data, and a daily commute that lets me repeat the same conditions multiple times to be sure it wasn't just a "fluke" data point. For my truck, wind resistance is the key, and seems to overshadow the minor efficiency gains the Cummins engine shows in "lab" charts at the preferred 1900 rpm.



I've talked to others with a similar amount of data that are just as sure that they get better mpg at 1900 rpm. I tend to suspect that "best rpm" varies between trucks, just as "best mpg" and "stock power" have been shown to be different. Everybody agrees mileage drops off above 2000 rpm, but below 2000 we seem to have different answers as to "best". I believe everyone should run a few tanks at 1600 to 1750 rpm, just to see where their truck stands. If you get better mpg and then decide your time is worth more than a few pennies, at least you'll be happier knowing what your truck is capable of.

JMHO, of course!

 

[fox]

My nephews 2001 3500 was getting about 14-15 empty highway. I asked him if I could go thru it and the answer was yes. We reset the lifters, ( only one was out of tollerance, exhaust on 6 ) So I snugged the hoses on the intercooler. All were loose , two I turned 4-6 turns with light wrist power.

His mileage is now 16-. We also checked the IAT sensor and sprayed it with brake cleaner. It was clean so I don't think it had any effect.

fox