New to 6.0 MPG?

[roadapple]

Hi all, new to diesel and to the forum. Recently purchased an 04 cc lb 4x4 6.0
and am a little confused by the mileage im seeing. It has 35 toyo mt's and a leveling kit. Bets iv seen is 15.1 on the overhead indicator and from what iv read those lie. My expectations might be high but i was hoping for better mpg All stock, tune, exhaust etc...I did a search on this and my mpg seems on the low end of the spectrum. Thoughts, suggestions, criticism all welcome

Note: This is a 40 mile hwy run @ 60-65 in cruise

[Karls03]

Disregard your MPG computer, it can't give you accurate numbers unless you can reprogram it for those 35s. However, if you can and/or have done this, 15 is about all I have seen on 35s in town. If you have not or can not reprogram simply divide miles traveled by gallons pumped THEN multiply that number by 1.09. The 1.09 (9%) is the correction factor from 31.5s that the truck was originally equipped with and the 34.6" tires you're rolling now. This number ONLY applies if you are still on the OEM 3.73s.

Most people are full of it when they claim any more that 15~17 on 35s in a 6.0. High mpg on the OEM 31s is possible, but not pushing 35 or taller.

[Lubbockguy1979]

sounds like you have unrealistic expectations. diesel trucks dont typically get 20+mpg. large tires and lifts dont help. the simple fix for your situation is not adding a chip, free flowing exhaust or a new air filter and associated tubing like every bone head in a magazine and tv show tells you either. companies pay those guys to sell their products and while they do have a use and can make improvements 80% of it is hype and focused on people that want lighter wallets. put the truck on a diet drop uneeded weight get some close to stock sized tires and slow down. your best mpgs will be between 60-65mph. i had two seprate trucks all of them 6.0 cc swb 4x4 automatics. untunes and tuned mpgs were within 1mpg. the only time i have seen a better gain than that was towing and it wasnt more than 3mpg and it wasnt consistant. i lost 2-3 with 35" tires on the 04. one thing to consider though if your spedo is not correct you are traveling faster than the spedo is registering and likewise it is not telling you how far you are actually going. this inaccuracy could make a 3-10% difference in your percieved mpg as well

[roadapple]

Originally Posted by Lubbockguy1979

sounds like you have unrealistic expectations. diesel trucks dont typically get 20+mpg. large tires and lifts dont help. the simple fix for your situation is not adding a chip, free flowing exhaust or a new air filter and associated tubing like every bone head in a magazine and tv show tells you either. companies pay those guys to sell their products and while they do have a use and can make improvements 80% of it is hype and focused on people that want lighter wallets. put the truck on a diet drop uneeded weight get some close to stock sized tires and slow down. your best mpgs will be between 60-65mph. i had two seprate trucks all of them 6.0 cc swb 4x4 automatics. untunes and tuned mpgs were within 1mpg. the only time i have seen a better gain than that was towing and it wasnt more than 3mpg and it wasnt consistant. i lost 2-3 with 35" tires on the 04. one thing to consider though if your spedo is not correct you are traveling faster than the spedo is registering and likewise it is not telling you how far you are actually going. this inaccuracy could make a 3-10% difference in your percieved mpg as well

Apparently my noted speed range went unnoticed
I have reprogrammed for the taller tire(595 rpm for 35's)
I do however agree with you. My expectations are unrealistic. My first change is gonna be an A/T tire as i dont like the M/T noise or vibration. What are your thoughts on cat delete, cetane boost or air intake?

[Karls03]

Yeah, I missed the speed range part. Allowing for the 9% error rate from tire size changes, that 60~65 mph in cruise indicated was actually 65~71 mph. I used a GPS and some math calculations to verify this in my truck on 35s. Sorry, I only have an XLT, no cool guy mpg liar on board, so have to do everything by hand.

My highway MPG varies, but I get between 16 (and on a rare occassion) 18 on the highway. The Edge I had was horrible for MPG, the SCT unit I have seems to help things out.

[Lubbockguy1979]

Originally Posted by roadapple

Apparently my noted speed range went unnoticed
I have reprogrammed for the taller tire(595 rpm for 35's)
I do however agree with you. My expectations are unrealistic. My first change is gonna be an A/T tire as i dont like the M/T noise or vibration. What are your thoughts on cat delete, cetane boost or air intake?

i noticed that after i posted sorry. im cheap so i pulled off the cat cleared it of the factory installed debris and reinstalled it. didnt notice much of anything in the way of a gain other then the possibility of it being a little louder. some people have posted great gains with the additives. i prefer not to order them online and have tried the ford brand cetane additive, ive tried the diesel kleen, staydyne and howes. after reading up on the additives i even ran 2 stroke oil as a additive and none of them made any significant difference for mpg. the 2 stroke oil seemed to quiet the truck a good bit. i probably ran the 2 stroke oil for nearly 2 years and honestly got tired of keeping it in the truck and having to divide it up into seprate containers so it would be faster to put in the tank at fill ups. i do use diesel kleen very occasionally and it probably isnt doing a thing for me other than in my mind cleaning the fuel system in which i change the fuel filters every 15k or so. alot of the additives to me seem like more or less a diesel version of a fuel injector cleaner that they would love you to use at every tank. alot of them dont do a whole lot of lubricity so using them at every fill up is kinda pointless in my opinion anyway.

[Lubbockguy1979]

also to note there are very few devices that change the spedometer. most of the time the rev/mile is for tranny shifting. the edge devices i think will show the correct mph only on their display. i never got the chance to verify that becase the short time i had a edge juice in my truck i had stock sized tires. the sct devices though will not correct your spedo

[Karls03]

SCT can correct 05 and above speedos, but not 03/04 speedos

[Lubbockguy1979]

yet one more tidbit to add. try not using cruise control. for me at first it was irritating but i seem to get better mpg not using cruise since on a hill i might loose a little speed and gain it going down one but unless it ia big hill i am not giving the truck alot of throttle and causing a downshift which the cruise will do. drive the turbo on hills by slowly accelerating right before you get to a hill to get the turbo spooled and then keep a small load on the truck and let the turbo help on hills

[Lubbockguy1979]

Originally Posted by Karls03

SCT can correct 05 and above speedos, but not 03/04 speedos

the sct as far as i know cannot access the abs module which is where the speed is set. the sct has very limited capabilities compared to other tuners as far as what it can do with modules but it does open alot of doors when tuning the pcm and tcm