Low rpm power for better mpg's?

[BigdaddyCtrain]

So in theory, if i can make a tune that has better low rpm power, that i can keep my rpm's down low and get better mileage, lower egt's, etc.

I don't have efi yet, but im saving for it soon, and i want to learn as much as possible to try and make some of my own tunes. I want a max potential race tune, Low rpm low shift point mileage tune, tow tune with good engine braking.

But for this thread i want to know the basics and possibly some in depth characteristics of a low rpm tune for mileage and daily driving. I can't find too much info on it, so if anyone has some ideas let me know!

Thanks!

 

[colorado.dmax]

Can't go too low before you start lugging the engine.

 

[BigdaddyCtrain]

My goal would be to accelerate around 1750ish rpms pretty good, and cruise at about 1200ish, without lugging.

 

[colorado.dmax]

1200 sounds too low to me. I'd keep it above 1400.

 

[RHallenbeck]

1700-2000 seems to be the cruising sweet spot on mine.

 

[Turbo Performance]

My goal would be to accelerate around 1750ish rpms pretty good, and cruise at about 1200ish, without lugging.

How do you intend to cruise at 1200 rpm? Going to have swap gears or roll on some big tires to cruise at that low of an rpm unless you're crawling down the road at stupid low mph.

 

[Dozerboy]

Yep.... and 1200 is too low the lowest you want to go is 1400. My truck gets better mileage at 60-65 then 55 in 6th gear.

Mileage tune consist in my experience of as much timing as you can run before it starts to rattle to much and low boost like 2psi while cruising.

 

[c20elephant]

1700-2000 seems to be the cruising sweet spot on mine.

X2, 2000 rpm @ 80mph nets me 19mpg to and from California last trip even on the long uphill grades..You might be able to attain the parameters you're looking for with a I-6 Cummin's and those are usually best in the 1500-1700 rpm range...

 

[BigdaddyCtrain]

i was meaning for in town cruising speed like 35mph, i do most of my driving in town.

 

[BigdaddyCtrain]

i thought cruising above 55 the tc locks and there isnt much tuning rpm wise that you can do?

 

[asmithIII]

Follow the tuning suggestions offered by dozeboy for cruising.
Lots of timing
Little boost
Keep revs up
I've tried many low rpm tunes before and none were very efficient. Thought that low rpm would be helpful but is not.

 

[S Phinney]

Peak torque occurs very near 2000 rpms. That sweet spot is there because it us most efficient at those rpms. Nothing you can do will change that. If you get your tuning where the truck just runs effortless you will accomplish what you are looking to do. The rest will be your driving style and fuel consistency.

 

[HotPursuit]

1300 rpm

Just a quick note, spent hours and miles with a 600hp CAT trying to get the best mileage...1200rpm seemed to do it.

Taking that to my Duramax....I seem to run best mileage at 1300-1400 and its running cooler... just saying

 

[Dozerboy]

What kind of load on your Cat? I don't do many long runs, but I see better mileage at 1300 or so. I also do Heavy Haul so Im grossing 150K+ and 525HP. We just got a Pete with a 600 cummins I can't wait to drive. Never driven a big cummins or many Pete's.