See, I dont get it. It's either: "I'm getting 23 mpg regularly with my 4x4 and you're not doing something right" or it's "I can't seem to get above 12mpg" Recently I saw an ad for a 97 ext cab 4x4 cummins and and the seller actually wrote in the ad that the truck gets 26mpg. I want to call him and see if he can gaurantee that statement or I get my money back.

Personally, I get 16-17 daily driving and 12-14 towing roughly 15-16k worth of cattle and trailer using 20% soy bio. Has anyone seen differences between biodiesel blends and regular? Neither me nor my father (dmax) have.

 

Mine's finally getting better after using Power Service Gray bottle. About 16 city now, haven't hit the highway yet.

 

20+ mpg claims aren't from folks driving around in a city. Get'er out on the highway for a trip that you can run 2-3 tanks of fuel or bring it out here and run it on my 600 mile a week hiway commute and your mpgs will increase . How much depends on several things, truck weight and oversize tires being the biggest mpg killer, along with city driving.
JIM

 

I get over 19mpg with my 37" Toyos on the '05...

 

i am know driving my 4th dodge diesel and still have never seen over 18 mpg , averge overhall of the four proably close to 13 . seems out of four trucks i would have at least got one as good as so many of you guys have got

stock-- oem tires-- under 70mph-- excellent care

 

I run B20 or B5 (winter) most of the time and I do see a very slight decrease in mileage (like .2 mpg) with B20, but that's probably within the margin of error in my calculations.

I've never seen much over 18 mpg either with my 2WD running empty on the highway, BTW.

 

J&L is right on. My 20+ mpg claims come from 2 specific driving conditions. Either droning down the interstate at 70 - 75 mph for a full tank, or near a full tank, or driving my truck to work for 3 full weeks.

As for driving the interstates, I generally don't run over 75 mph (in a 70 mph zone). At 5 over, I can have 8 cops radaring me and 2 cops lasering me, and they'll never do a thing. I'm never in any hurry to get where I'm going so 5 over the speed limits is about as stress free as it gets. I'm not getting ran over at that speed, I'm not running over anybody at that speed, I don't even have to consider the possibility of getting a speeding ticket, AND (most importantly to me ... because I'm cheap) my fuel economy is about as good as it gets. So yes, with a 6 speed 4X4 Quad, long bed, I can get 20+ mpg on a long interstate cruise.

As for my "around town" commute to work (which I don't do generally, that's what the rice-a-roni car is for), I live out in the country. I have a 22 mile commute to work on back country roads. There are 3 stops signs and 1 traffic light (that I usually get green). If I drive a full tank of that spiritedly, I'd probably get 17 to 18 mpg ... if I drive it like granny, I have gotten over 20 mpg (over 700 miles on the tank).

Admittedly I drive much different than most people. Because even though I have a huge truck that could be stunning in its ability to drink fuel, I look for every way I can WHILE I'M DRIVING to use as little fuel as possible. I really don't see any purpose to use any more fuel than I absolutely have to. Its just plain wastefull and costs ME.

And, look what I bought. When I was considering trucks, I had a 3/4 ton Suburban 4X4 with a 5.7L. Not too shabby of a truck, but wouldn't tow for squat (looking back on it now), and got about 8 or 9 mpg towing a 16 foot enclosed trailer (about 3,000 lbs total).

I choose: Cummins power over the PSD (no DMax at the time), because of its simplicity, its track record, and because 6 cylinders at 5.9 Liters was outperforming 8 cylinders at 7.3 Liters (at the time). It seemed a better package (and it was/is). I could have bought any number of trucks and gotten squat for mileage (Ford V10, Dodge V10 are examples).

Your daily driving mpg sounds normal to me, and your towing mpg sounds phenomal towing that much weight. See my post 1 page back about my towing mileage. You're doing great in the 12 - 14 mpg range towing IMHO.

 

Running stock 245's.

50 mile interstate commute at 65mph. Last tank calc'd 20.4.

When I pull my 3500# trailer with 2 1100# horses in it I average about 15.

 

How big of an effect does the motor and pump have? It seems like the electronic injection pump would be much more efficient than a manual style pump. Any truth to that idea?

 

I'd agree with that.

 

SO many posts, mine will get lost but my daily drive is just over 3 miles to work with 4 stop signs and one light. I usually put 2-300 miles pulling my 2500lb bass boat per tank and I will get 16.5 to 18 mpg and somewhere over 500 miles per fillup.
On the highway and without a trailer I have gotten 23 plus a couple times. Almost always over 20 except for when I had a truckful of people with a bed full of luggage running late for a cruise I got 19.8 doing more 80 plus than 80 minus.
All these were with either rv275's or the Edge 3's. I now have the F1 1.6 and haven't done a highway test but they should do well.

 

What we all have to realize is that we all live in different parts of the US/N. America... This equates to different elevations. Also, the 4x4 vs 2wd is a valid point. But the auto vs manual is a little skewed... The Auto has a .69 overdrive and a lockup, the manual a .73 and a clutch. There is no slippage in either if you are driving at highway speeds in OD. Oversize tires can kill mileage, but not always. Mechanical pumps can be just as efficient; it's more in the injectors and if the pump's output pressures are healthy (timing makes a difference too). Higher psi = finer mist = more complete burn = more power = less throttle to go the same speed. Injectors with more holes in them would be a good idea to get your added power AND mileage. This is why I am looking into 7 hole nippendenso nozzles for my truck.

My truck gets about 12mpg in the city, but I have a really heavy foot at stoplights... On the highway my truck averages anywhere from 22-25mpg. I do run the Diesel Power Service white bottle in my truck (winter; grey in the summer). I drove a 2k trip from California to Wisconsin at 70-95 miles per hour (I was in a bit of a hurry) and still managed an average of 22.4mpg

 

As I understand it, even when an auto is in OD lock-up, there is still some slippage. Only about 90 to 95% efficient as compared to 100% efficiency with a healthy clutch. Not trying to say there is no energy loss in a clutch, but comparing relativities. How to explain ... the condition of the clutch at 70 mph in top gear let's say is 1 (or 100%). The efficiency of a comparable healthy auto would be somewhere in the neighborhood of 0.9 - 0.95 (90% - 95%).

But I may be full of Krispy Kreme donuts.

 

I'm not sure if all modern auto trannies are the same, but I thought the TC lockup solenoid electro-mechanically connects the flex plate to the input shaft? And since OD isn't a fluid coupling, it should be either on/off...

 

I get 24-26 (canadian MPG) if I keep my speed just under 100kmh (about 60mph) ligtly loaded (a few hunderd pounds of stuff in the box). If I go up to 120km (about 75mph I think), it drops down to 22mpg. If I throw a sled on the deck (one sled, or tow a light utitlity trailer, it will drop to 18-20), two sleds on the deck running at 120km (i'm always in a hurry when I am sledding ) and I could go down to 16-17mpg. If I pull the parrents travel trailer at 120kmh in the mountains, then we are talking 13-14 they way I drive it (WOT in all passing lanes, pass em all if you can).

Most of my driving is into town for some supplies then hiway to the job site, pretty much the daily routeen, about 10k in town, 120k hiway before I am home again)

I'm considering improving the intake with an AEF and maybe a TAG. I don't know if I want a stage two, I would like the sound of the turbo for about 5 minutes then want it off again. I would hope for 1mpg or a bit more from these two additions. I have heard some timing changes can get you 1 to 2 more, might consider something for that. Buddy next door bought something (can't remember what, has 5 levels, sits in the A-piller, grey with an LCD display), he halls LD every day, said that got him a few 100km of range, he is also running an aux tank though. Said it paid for itself in a month but he burns a lot.