Cummins 400 B.C. MPG?

[290smallcam]

Quick question. Looking at putting a 400 in my M 813. Those of you that are running them what MPG are you getting? Or should I just stay with my turbo NHC 250?? That gets around 8-9 MPG empty with 16:00R20's.

 

[simp5782]

In a 5 ton

Around 8 to 9 with a .83 OD in the 16 speed on 1600s. It also weighed 27,000lbs.

7mpg with an empty 13,000lb M322 trailer in tow

5 to 5.5 with a loaded trailer. 60,000lb and heavier

In a 915A1 with 12R24.5s
Empty at 23,000lbs. Direct drive 9mpg.
Empty 870 lowboy at 45k 6.5mpg
Loaded 4.5 to 5.5

920 empty at 58mph 7mpg. This is with aneroid and HT4B turbo.

All of my engines have 250 rail pressure. #5 or #10 buttons and no aneroids so I lose fuel thru thru rolling coal. I also rub 220cc injectors and larger HT4B turbos on the 923 and 915

MPG loaded, m915 vs M916 vs M920 ?

I was trying to figure a few things out, and I wanted to try and compare mpg on the trucks, as close to apples to apples as it could get. Loaded, being around 80k gross (or more, but 80k for a solid comparison.) And the 915 could be the older with the cat 7155 transmission and the A1 with the...

www.steelsoldiers.com

 

[290smallcam]

Ok so no real gains. Was hopping in the 12's but didn't think 9mpg! Was thinking of removing the fan and the fan spacer, to move the radiator back. Installing electric fan and adding an air to air after cooler. That might get me more MPG? All that's done to the motor is, add S.C. 290 cam and timing. Plus HT3B turbo. I'm not looking for jobs of HP, but more MPG.

 

[simp5782]

Add a pressure gauge so you can tell where your throttle is when driving. Especially cruising it will show you where you may be running 50psi down the road. You can maintain the same speed by running 30psi with just letting off your foot a tad.