As for the Crazy Larry, its an agressive tune that advances the timing pretty far. Advanced injection timing makes much better throttle responce and ups the MPG by a more complete burn. As long as you are extremely easy on the go pedal the Crazy Larry tune would up your mpg's. Its just so hard to have that much power and not use it to pass or take off fast from stop lights.

 

Hand calulation, no. However,if you install the ROK teck, senser, accellerate slowly to 50 mph (where the O.D. engages assuming you have an automatic) turn "on" the cruise control,and slowly let up on the fuel and slow to about 35 mph trying to keep the tranny in OD while watching the rpms, THEN reset the overhead, THEN, engage cruise I would say it is possible.

 

The truck in Diesel Power Mag was a 95' or 96' Auto Ext. Cab 2x4 3500 Dually. First they got 26 mpg with it and then got 30, and that was with the dually fenders still on. I don't think it was coasting down a hill either, so it should be possible to get 28 mpg in a CR.

 

Could this be the newest "X Challenge"?

If so, count me in. I, too, saw that article on the dually getting 30MPG on the highway. Since then, I've thought a lot about how I could get that kind of mileage out of a Cummins Ram.

I still had my gen II gasser at the time, and it inspired me to get the diesel so I can tweak for mileage. Seriously.

I hereby state my personal goal of getting 28MPG out of my 2004.5 HO without looking like a tool in the process.

Things I'm looking at:

aerodynamic mods such as a bed cover, 86 the towing mirrors, mod the air dam, tailgate spoiler, underbody panels and perhaps even a grill insert.

drivetrain mods like higher gears or a GV overdrive unit and synthetic oils.

engine mods like new software, synthetic oil, electric fans, and a higher temp thermostat.

I'm not towing 15K# trailers with my truck. My average trailer weight is in the 8K# range (although I tow up some serious grades), so I can afford to lose some power/gearing towards this endeavor.

Never say it can't be done. When someone comes along with the willpower and cash, it can be accomplished.

garrett

 

I also think it can be done, but the mods will take you away from the capabilities of a pickup truck. At a certain point you have to wonder if it is all worth it, or you can just go buy a fuel effiecient car.

 

Well, first, it's a great challenge. Maybe not on the level of putting a man on the moon or breaking the sound barrier, but a challenge nonetheless.

Second, you can do many of these mods without adversely affecting your truck's abilities. Your may lose a little power, gearing, or asthetics, but with proper moderation I'm sure it can be done.

I'll be starting on my quest shortly here. Right now I'm working full-time, finishing my paramedic courses and moving. Needless to say, I just need my trucks to get me from point A to point B until I'm settled down.

In the summer I should be back to normal. I'll report findings as they come!

garrett

 

The 5.9 Cummins is the most fuel efficient diesel motor out there for the power.
When I lived in OZ I has a mitsubishi pajero with a 2.5 turbo diesel. Every day I went to work, 60 miles each way. I fuelled every day, as I had free fuel and while fuelling the equipment, they would top off my truck. 33 liters every day, hail rain or shine. that's 8.9 gallons or 13 mpg. My Isuzu trooper, 2.8 turbo was doing well to get 18mpg.
Don't despair guys. If you need more fuel economy, wait for the 1500 diesel.

 

Someone should try running the smarty on #o..........half power. I tried but couldn't stand the gutless slug response. Hey wheatwacker I too lived downunder for a year. We used to call them poofter pajero's.....no offense intented mate! Best I've seen was 21.3 mpg empty.

 

My friend got 29 MPG in his 03 going from Amarillo to Denton (Downhill). He drove 55 MPH with a tailwind.

 

Dad has an '03 with a six speed, 2wd QC long bed, he gets 24-25 running 70 (I know because i hand calculated it) empty with no wind. He has the edge EZ set on two, other than that its bone stock. I'm sure if he backed it down to 55 or so he could get 28.

 

Hi I am new to your forum I have an 05 QC 4x2 short bed 68000 miles on it . i have a tonneau cover and amsoil 4510 filter, torque tube with 5" exhaust and smarty jr on economy level, 3:42 gears and stock tires 245/70/17 on stock alloys. I can only get 22.8 mpg driving 55-60 mph on hwy hand calculated .If you guys have any tips on how to get 25 mpg I would love to hear them . Thank"s

 

Hello,

No need to make truck changes. Get er up to OD speed and then back down. On relatively flat terrain I can get better than 28mpg. Big problem. I do not want to die. Doing 45 to 50 on the highway is stupid in my opinion.

Damon

 

The highest my father in law gets is 23mpg, with a 04.5 2wd, QC Long bed. He gets about 15mpg towing his 5th wheel (don't know the weight on it).

 

Improving mileage can only be done two ways.

1. Reduce resistance. This can be done by airing up tires, folding in mirrors, smoothing the grill, adding a tonneau or topper etc. It can also be done mechanically- synthetic oils, locking hubs, 2wd vs 4wd, etc.

There are external factors of resistance as well. Ambient temperature, Wind speed and direction, road surface, terrain (hills, mountains) etc.

2. Improve efficiency of motor/transmission - programmers, Intakes, Exhaust, Cams etc.

Basically any motor needs to provide "X" amount of power to overcome the resistance at a given speed. It doesn't matter if your motor is tuned to 600hp or 170hp (Smarty on 0) it will still take X hp to overcome that resistance. If you reduce the resistance, you reduce the amount of hp heeded and will see a mileage increase. If you improve the efficiency of the motor, then it will take less fuel to provide the hp needed, and improve the mileage.

I think you could get to 28mpg in a test scenario. If you did everything you could to smooth your 03 2wd truck out. Drove it at it's ideal speed for mileage (determined by months of testing beforehand) on the perfect day (75-80 degrees and no wind) on a flat road with no stops and no traffic, it's possible. But in real world driving on a regular basis, IMO it's not possible.

 

Hoist a sail !!!