I guess that zone will depend on your gears and tranny too.. Try this link for the white paper.

http://cumminsengines.com/assets/pdf...whitepaper.pdf

 

Good link thanks. I think dzl-damon is correct in observing that the engines under that test are bigger, lower speed ones than ours. Mine "likes" rpms well above 1500 as I said. Another point is mysteryman's warning against putting low-rpm power through our Getrag gearboxes. All the other points on tire pressures, driving strategies and so on are highly applicable to this topic.

 

I can't figgure how you guys with W250's are getting in the low 20's, i drove a tank of summer fuel out at 60-65, never blew any smoke and kept the boost below 10psi and could just sqwek out 18.5 mpg.

i get 16-17 driving to and from work 8 miles hwy, 3 miles country roads, 1 mile town.

Dar

 

Its sound like to me You finally reached Full operating temp then you shut it down.
I live out in the sticks.
My truck takes a minimum of 7 miles to get to operating temp.
I live 1.5 mile @ 35mph to the stop sign then the speed goes up to 55.
Also 90% of the time when ever i start my truck i put on 50 miles minimum.

 

Bob i can buy the 16-17 with the way i drive, but i can't understand the full tank @ 18.5, i mean i milked that sucker for everything i had, and then some guys with a slip-o-matic A518/3:54 with 33 inch tires say they get 22-24 mpg...i ain't buyin it.

by the way it's nobody in this thread.

i really don't think they know how to really chech there milage.

Dar

 

best mpg I ever got was 20 US mpg going a contant 60 on my stock 91 with an auto and balding 235/85/16 toyo tires on a 150mile trip.

Best I ever got over a whole tank was about 18mpg in the dead of winter (#1 diesel) on 255/85/16 toyo m55s. truck had ddp injectors, he351cw, 4" ex, dennyt pin, valet closed, and a dying auto trans going roughly 60mph. all highway

 

I've tried 3 different sets of injectors, 2 turbos, all different types of afc settings including shutting off boost to it, I've had timing everywhere from 1/8" to where it is now... on the highway i always get 17mpg. 285-75-16 tires with 40psi.

 

I wanna see something and I need confirmation.

Both 4.10 rear geared truck I had were 4x4 but the 2wd was a 3.54. I think I am seeing a trend. 4.10s get better mileage than the 3.54 counter-parts.

Best MPGs:

93 4x4 4.10 G360 stock tire 21mpgs
93 2wd 3.54 auto stock tire 17mpgs
92 4x4 4.10 G360 33x12.5 23mpgs

Someone want to help keep this simple list going?
Posted via Velocity LG ALLY

 

I'm with ya...i have had 4 cummins trucks, 1 VE, 2 P7100, 1 VP44, the 1 and only truck with 4:10's got the best MPG.

Dar

 

Are these MPGs the best you ever got? Or are they average MPGs.

 

In order to get to TRUE MPG you have to hand fill your tank.

With diesel you get a lot of foam with a high speed pump. So you'll never get the same level of fuel when it shuts off.

 

Best. Average is about 2-3 less.

Trucks were filled on low speed, truck rocked, filled on low till I could see it in the neck. Then hand calculated.

Posted via Velocity LG ALLY

 

Is it because a 4.10 equipped truck is usually not run as high a rate of speed, aerodynamics play a big role in fuel mileage and higher speeds=increasing aerodynamic friction?

 

Take a look at what Cummins gives a stock truck:

3/4 ton 2WD with manual, street tires and
3.54 axle: 23 enpty, 20 loaded, 12 -17 mpg towing
4.10 axle: 21 empty, 19 loaded, 12 -16 mpg towing

3/4 ton 2WD with automatic, street tires and
3.07 axle and 3 speed auto: 20 empty, 18 loaded, 12 -16 mpg towing
3.54 axle: 21 enpty, 19 loaded, 12 -16 mpg towing
4.10 axle: 20 empty, 18 loaded, 12 - 16 mpg towing

3/4 ton 4WD with manual, trail tires and
3.54 axle: 22 enpty, 19 loaded, 12 -16 mpg towing
4.10 axle: 20 empty, 18 loaded, 12-16 mpg towing

3/4 ton 4WD with automatic, trail tires and
3.54 axle: 21 empty, 18 loaded, 12 -16 mpg towing
4.10 axle: 20 empty, 18 loaded, 12-15 mpg towing

Aerodynamics is one thing to play with, but how much, to what end and cost. I guess you could lower it, add flat plates underneath for air flow, miser type injectors, smaller mirrors and moon hubcaps but there goes the fun factor.

Cummins claims a 30% difference in MPG between a good driver and a bad one, now that I can see.

My Ramcharger doesn't do that great around town 15 mpg or so. It all depends on DC traffic, and at 10-20 MPH I'm thinking aerodynamics doesn't play a part. I can say that on a Denver to DC run I got 20 mpg (GPS). One of these days I'd like to try a timing bump and get a turbo off a 2nd Gen. The wifes 2nd gen will get 20-23 mpg all day long. Both are auto's w/OD.

 

YA Whats this all about ????????????????????????