MPG for my MBN CAT?

Setting the cruise uses more fuel, you can see a hill, even if it's a small one and may just let the truck slow a little and pick back up, the cruise will just try to hold that speed, I haul lite loads like you and get way better fuel milage without cruise. What mufflers do you have on the truck?

 

Is ur cruise set on soft or hard.If it's been a while on the overhead would'nt hurt to run it and pressure test CAC.It's alot of good info on here to get the MBN to run great.But to answer ur question, 6mpg sounds above avg for a stock MBN without any mods.

 

I agree, 6 sounds pretty good for a stock MBN. Gonna have to get Mr.Haney to either flash it to at least a 6NZ (or 7CZ) or better yet a PDI file.

I'm assuming the converter(s) have fallen off already?

 

I get better mileage using my cruise control but when I start climbing a hill, I set it off and run it manual.

 

I run mine at 1400 rpm and run bout 58 mph and getting bout 7 to 7.5 mpg. Remember, Im in Cali and the speed limit is 55 .

 

6.0 is excellent mpg's for a stock MBN. When I first got mine people here said i'd be lucky if I got 4.5 to 5.0 I got lucky in stock form it avgd 5.6mpg. Put a fuel temp wire on, upgraded turbo to borg warner non wastegated, and got Haney to flash it 6NZ 550hp 2300rpm braksaver. Last 120,000 miles since that 5.8 mpg admittedly tho i do have a heavy foot and could probably pick up a couple more tenths with a lighter foot. I typically cruise at either 1600 or 1700 rpms. I agree with others about cruise control, dont use it, drive by your boost gauge keeping it low and only using as much throttle as necessary getting/maintaining speed. Youll beat the cruise every time. And run the overhead every 100k miles whether its needing it or not. You never know what the visual inspection of the valvetrain while theyre in there adjusting might catch.

 

I got roughly 4.9mpg out of my mbn .The type of work I do with the truck there is a lot of idle time and pto time.But I have a 02 n-14 cummins that religiously gets high 6 mpg doing the same work.about three weeks ago head gasket let go.in the mbn so after a good consultation with mr haney,I am in the process of un bridging the cat,after talking with mr haney he said that I should see a significant increase in fuel economy,after the rebuild with the new parts and reprogrammed ECM.
I pull a bulk pneumatic as well and have been very happy if could have seen 6 mpg average,but no such luck.
I can't wait to get it all back together to see the difference in fuel economy!!