Guilty as charged

 

I get 20 plus no problem, 4X4 DUALLY

 

OK, guess I need my numbers added to this topic. On my 04.5 auto 4x4 I barely got 15-16 highway mpg running an Quad intake and Quad XZT chip on an empty truck. After many fuel related problems finally traded for the 07 5.9 auto 4x4 in my signature and this truck is almost (other than the color) a clone of the 04.5 truck (tranny shifts better also but still a 48RE). Definatly much better milleage and much more dependable truck. Absolutly no problems so far at 25K miles. Run last year, truck only, no fith wheel from Tampa Florida to Jackson Mi and back over 7 days, running 70-80 mph (about 2100 rpm, got a hand caluclated 21-22 mpg and I did not baby the truck. Only had 16000 miles on it then also so per prior discussions it wasn't even broken in yet. OH yeah it also had the Quad X2 box set n the milleage setting. Last few trips have been with 5er so mileage is a little less, usually around 10-12 mpg but truck/trailer together is almost 20000 lbs so guess that isn't very bad either. (PS the 04.5 towing same weight barely got 7-8)

Therefore I as someone else posted truly believe that it depends on tthe truck and they can be radically different as far as mileage yet be almost identical trucks.

JMHO I guess......

 

I have a 2006 2WD Dually, consistantly getting hand calculated milage of
21.7-22.1 freeway no load.

 

I have an 06 5.9 and can do 20 or so if I am gentle on the truck and keep it under 2K RPMS on the freeway. I think any 3rd Gen 5.9's are good trucks and will do about the same things with a comparable programmer. They should all be capable of 18+MPG if driven normal with stock size tires and proper maintenance. Anything outside of that is a crap shoot. Scotty

 

2WD/5600

For the calendar year, (out-of-town 6 times; max of 50 miles each way; no towing):

Averaging 400 miles per fill-up (21 gls) at 19 mpg. That's ALL fuel and ALL miles kept in 12-column ledger.

I expected -- hoped for -- 20 mpg highway, but never expected fuel mileage to average this high for in-town miles. The average speed was 29 mph, so it pays to take the slightly-longer-but-no-stops-route where possible.

Key for any of these trucks is, IMO, keep average speed high, but peak speed low. And, of course, never come to a full stop, as the weight of the truck is a killer from a standing start.

Have seen a chart on another site that correlates pyrometer temps and mpg. Basically, between 500-600F is the sweet spot. I believe 1700-1900 rpm is ideal, with 1750-1800 rpm perfect. If that means 33 mph at 1900 in a 40 mph zone, THAT is what works.

 

06 5.9 4x4 273 gears 20 mpg highway at 65 mph 17 to 18 city
17 mpg highway puling a 7x12 inclose traler 2 motorcycles + gear

 

In the summer I was making about 16mpg hand calculated and empty prior to installing the Edge and 18 to 21mpg running on level 1 with mostly interstate driving @ 75. Once made 23 MPG at speeds even higher (great tail wind that day ).

Lately I’m lucky to break 15, but it is cold (-9F and lower) and I’m running a winter blend of diesel. Hoping a winter front will help out a little here as well as keep me warm in the cab… will find out next week.

Like Ram Daddy, I believe a 2wd would most certainly get better mileage (Dad’s got a stock 01 2wd and consistently gets 20-22). Something to keep in mind when comparing mileage.

 

I had Tim's tranny mods for a long time and never saw that kind of mileage. I do have 4.10's though. Those mods finally gave out with Beta 4.4 and now I have a goerends that holds the power no problem but I didn't get any great mileage increase with it. Those are some good numbersd, but as pointed out, there are way too many variables. I would bet if I drove the 22mpg trucks, it would be more like 17-18 and thats not hotrodding, just the way I drive.

 

I never got any great fuel mileage until I bought guages and drove the truck using the boost and pyrometer guages. That is one of the most important things about getting great fuel mileage in my opinion. I have gotten 22mpg hand calculated w/ 37" tires (actually 36" true height), but I drove it like an old lady at 60mph tops, no idling, and slow take off and rolling neutral stops. That was with the Smarty on 90hp setting. Most of the time on normal driving I get 17.5 to 18mpg.

 

Completely stock 05 325/600 3.73's 4x4 21.6mpg hand calculated freeway 65mph, no traffic to deal with, not likely to be able to drive that easy very often. Now, only change being 33.5" mud terrain tires more like 17-18mpg empty highway, 14-15mpg mixed driving, and 12-13.5mpg, 60-70mph, towing a flat front cargo trailer weighing only 6k. I don't baby it or beat on it, but do get into it once in awhile. Truck is very well maintained by myself.

 

Last time I made the trip from Utah to Idaho I ran 65mph the entire time (cruise) and got 25mpg with every tank. I run very conservative fueling, twin turbos, and a Goerends tranny. I got 21 consistently, before the turbos and tranny, running the Predator and puck.

 

Recently getting 15 mpg hand calculated. That is mixed hwy/city. I did hit a high of 18 mpg one time on a trip. Edge EZ set on 4 all the time.
Always keep it under 70 MPH.
All mods as listed in sig and with soft tonneau cover.

 

I have early 04 with auto and 3.73 gears... despite all the mods, my mileage remained very close. Smarty took it up a little, right foot dropped it back down...

All in all I average 20-23 mpg with mostly freeway + mountain driving. I got bests of 25+ going from Reno to Las Vegas one time and 24 going back and forth to Reno from home. That is all 65 mph driving.

 

I get between 15 and 21 stock depending where my foot is . But thats gonna change when I lift it and put some bigger tires on it .