Timing and 4.10 Ratio

[Flat_Lick_Dodge]

First off I would like to thank everyone for their valued input on some of my questions and statements.

I have been reading these posts, just about all of them, when I get home from work at night and have learned a lot from you guys. I bought my ctd for longevity and efficiency. I am still comfortable with the longevity but am still concerned with the mpgs. I am pretty much green horn on the cummins, But I have been reading these posts and looking at signatures and I could be mistaken, but it seems that the trucks with 4. 10 gears and electronics that alter the timing seem to be getting the mpgs that a lot of us are looking for. Also, would like to make a note to all of the 2wd ctds. The 2wd will most always get better mpg than a 4wd. What is the sweet spot on the tach? Is it where the torque is highest and should I try to pull in that rpm range. That's my initial thinking.

 

[Scrappy]

peak torque is @ 1400 rpms, With mine I try to keep it between 15-2000 empty and at least 1600 towing. the lowerthe better until you get to 1600. below that and it is hard on clutches in the manuals and line press. in the auto is too low(causes the clutches in the T/C and transmission to be more likely to slip.

 

[Boonieman]

Although my truck is older than yours, it likes the 1800 rpm range. If I start running above 2000 rpm's, the mpg falls off dramatically. Mine started out in the 14 mpg range new and started doing better at the 5000 mile mark. It continued to do better until about 14000 miles where it leveled off. I manually log and calculate my mileage, and have since the truck was new. I've got almost 40000 miles on the truck and the last 12 month average mpg was 19. 6. I wish I had got the 3:73 gears because I only pull about 8000# normally and it would have easily handled that with 3:73's, hills or no hills and I think I would have gotten slightly better mileage. Hope you enjoy the truck. I love mine.

 

[Flat_Lick_Dodge]

Thanks, I was really disheartened with the mpgs. You have given me a little hope for better mpgs as mine breaks in. I have 4k on it now and it seems to be creeping up a little. Maybe I am being more aware of my driving habits too. At any rate I like what I am seeing. I dont tow that much and probably 8k to 10k will max me out too. The 3. 73 does really good with 8k cant hardly tell its back there. I drove 276 miles empty on I-75 138 miles each way about 10 of that was in Lexington, KY, then loaded the trailer with the tractor I have and drove about 43 miles each way 5 miles each way is a mother, huge steep hills with 3 or 4 switchbacks and not going over 10 or 15 miles per hour on some of the hills. I got 14. 87 mpgs hand calculated adn filling the tank until the neck is full both times. The overhead showed 16. 1.

 

[drewRoberts]

the harder you work the engine the quicker it will break in and the better the mileage will be.



try this though, get a bottle or Power Service Diesel Kleen (grey bottle) from wallyworld and put 16oz in each tank. Ive been experimenting around with this stuff and have been averaging about 2mpg better than not useing it. that equals about $7 savings per tank and the 32oz bottle only costs about $5. adding more than 32oz doesnt increase mileage, but I have been adding about 8oz of Marvels mystery oil to the tank, that didnt do much, but it did quiet the injectors a good bit