that is why in my original post i made sure to say larger numbers, not larger gears.

cumminalong: thanks, that makes sense. as far as figuring my best rpms for mpgs, i guess the only way to do that is trial and error? no magic formula for that?

 

Nope, just gotta figure out where your truck gets it's best mileage right now.

I know for me, personally, I get the best mileage when my truck sits in the 1700 - 2000 RPM range.

Also, what I've found is even more important than the RPM range is the boost and egt numbers.

As soon as I start going into double digits on the boost, my mileage goes to crap. Go figure, more air = more fuel.

On the EGT's, if I can keep them hovering in the 550 - 650 degree range, it seems to be happy. Any higher than that on flat level ground, unloaded and most likely you are lugging the engine and burning unnecessary fuel. Below that an your burn isn't as efficient.

1700 - 2000 rpm's seems to keep me in 20 - 21.5 MPG range on the highway.

If you go back to one of my posts (I think it was around the May '07 timeframe), I did a trip write up where I went from Georgia - Missouri - Ohio - Georgia and did a comparision of speeds, Edge settings, RPM's, etc and logged it all down. It may help you out a bit.

Just search my user name and trip report and you should find it.

Hope that helps

Rich

 

towrig, wasnt calling you out or anything LOL just for anyone reading it, a lot of people confuse it. Kinda like saying left instead of west or up instead of north.

Yep 1700-2000 I'm general is where youll get the best mpg. Yall have a lot more control with other aspects of the engine to get better mpg, pretty sure it was moparman that's got some write ups.

 

Another thing to look at is the timing of the injection cycle. In stock form it is a little too retarded (the timing, not me. I already know I am) for optimum fuel mileage.

That's one of the reasons that the previous gen Rams got better mileage. 1 - they produced less power and 2 - that noise you heard frm them was mainly due to the earlier injection cycle and combustion noise.

Obviously, you'd need a programmer or box that lets you play with this a bit to really figure it out for your specfic purposes.

One good person to talk to would be Triton. I know he's running 37's but is still getting real good mileage. Again, the programming has a lot to do with it. But, obviously, he already has a lot of the experimentation done.

 

yeah, i've got the smarty, but i still run stock for now. i bought it when i could get a decent deal cause i know i'm gonna use it. i just wanted to put more miles on it first to make sure i have no warranty issues. since i rarely get to drive the ram because of having to drive the company truck for now, i havent used the smarty much. i did use it to recal my tire size though. i went a little larger than stock, at 315's. they measure to about 33.6". before i use the smarty on a regular basis i prob want to have between 5 and 10k on the odometer. as it sits right now, it has under 1700 miles on the clock, but barely. i do get to drive it to CO in a week and a half though and tow my jeep up there to have some fun! that will put about 2k more on there! still wont be time for my first oil change though...[&:]

ps- i bought the ram at the very beginning of november, and it already had about 500 miles on it...

 

Yeah, stay out of the programming game until you get a good 10K on her. Then you "know" that most of the bugs are worked out.

Good call there.

 

I figured that this is a good time to add my findings as of yet. My rear end ratio is a 3.73
I've upgraded my tires from a 235/80/17 to 265/70/19.5
The stockers were 31.8" in diameter and 9.3 wide opposed to the new 19.5's that are 34" and 10.3 wide.
As with the stockers, travelling at 70 mph, I was at about 2000 rpm's.
With the 19.5's at the same speed (as per gps, I haven't re-calerbrated the speedo yet), my rpm's were about 1750

My rpm's dropped significally, but there's a whole lot more mass to get rolling up to speed. Fortunately the majority of my driving is highway miles, and I'm hoping to see simular or even better mpg.
One thing I noticed right off the bat was a decrese in power at the same setting with the edge.
If I can see better mpg's, I might be able to live with the power issue, or just bump up the stting more when I want it.

Hope that this helps.......

 

RAMITONE: i suck of the line,once its moving its way much better but as soon i hit throttle i must go to 2nd and about a 2 sec later i must shift into 3 then there its really nice
and i dont have a chassis cab,this is a 8'box truck witch i removed the box.... i have 3.55 per dealer and dodge reports