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cant get any kind of mpgs....

4K views 32 replies 9 participants last post by  geared_low550 
#1 ·
my 2008 in the sig is what i'm talking about, i can't get over 14 mpg out of it no matter what i do. any ideas? i tried several tunes, the one i am having the best luck with is a tune i got from matt at gear head performance. which is where i'm getting 14. when cruising at about 60 mph egts are about 620 -650 depending on headwind and the road. gears are 3:73 and tires are a 33x12.5x18. and yes the speedo is correct as these are an inch taller than my stock tires.
 
#2 ·
You're getting about what one would expect from your configuration - maybe a bit low.

Your auto and 4x4 are kicking your MPG in the crotch. Your EGT seems too high to me. I run 450 degrees at 60 MPH (no wind).

Chucking the auto & 4x4 are out of the question, so the only recommendation I have is get a tonneau cover. Those are good for an extra 1.5 MPG over what you are getting now.
 
#3 ·
make sure your hubs are unlocked... they will cause it to go down
 
#4 ·
im not sure i can unlock my hubs, they are automatic hubs, it says locked or auto on them, are these the same as the older style manual hubs?
 
#5 ·
When you have the hubs in "auto" you need to reverse in 2wd to get them to unlock. I'm assuming you use reverse in your truck, so that should have happened anyway, but it is worth a try...
 
#6 ·
well i knew you had to do that to unlock them, i also have noticed a 2 mpg improvement by cutting down idle time
 
#7 ·
What are other 6.4's with similar mods seeing for mpg?
 
#8 ·
well everyone i asked about it tells me they see 16-18 under normal city and highway and some claim 22-24 highway with the spartan tunes.
 
#9 ·
That seems real high to me. Our 6.4 gets 11. I couldn't see gaining 11 more mpg with a tune and a DPF delete.
 
#10 ·
mine got 10 until i did anything to it, but my dad has a cc sb 4x4 6.4 and gets 16-19 every tank hand figured, we even switched trucks and mileage stayed the same on each for 3 days worth of driving
 
#15 ·
10 seems horrid stock! I heard the trucks gain mileage as they get more miles on them, but i don't know how true that is. My 6.0 gets about 14 city 19 hwy. Are the 6.4's supposed to be better?
 
#12 ·
yea throw 2200 more bucks at it LOL LOL and junk a little more than half that ...
 
#14 ·
LMFAO o yea i'm on the helium, and no spartan files can't be put on an sct, at least i don't have the ability to do that. i do have a nice street file from matt, i reallt like it, no smoke, lower temps it's nice.
 
#16 ·
my dealer told me that they get worse mileage, yet they are suppose to be more efficient according to ford. i have 23,000 on my truck and my dad has under 5,000 on his.
 
#17 ·
Our tow rig gets 15 empty and 12-10 pulling. thats the best its ever done.
2008 crew cab dually king ranch :D NO MODS ALL STOCK!
 
#20 ·
What's the gear ratio?
 
#22 ·
How does it get 15 on 4.10's when most stock trucks with 3.73's can't get that? I have to say you got a lucky 6.4 there! BTW, my Dad's has 4.88's...
 
#25 ·
you are lucky to get 15 out of it overstroked
 
#26 ·
damn are all you other 6.4 guys getting that bad?? How many miles do you guys have on them? cause like I said 15 was the best its ever got and that probally didnt start happening untill about 80-,90,000. Maybe your guys will get better after some more break in time????If so I guess we are.LOL

The other 2 trucks I run at work (not mine) only get 11.8-12 according to the idiot gauge in dash. Thats all it ever says LOL. but they are all high speed city driving. Lots of stop and go full throttle take offs! LOL
 
#30 ·
well, I do think that's low mpg's. the tonneau cover really will help, mostly on the highway.
I assume you're trying to drive it easy for mileage? if not, that'd be a great place to start.
 
#31 ·
yes i have been driving it easy. i put my stock tires back on and i noticed my EGTS have dropped about 50-100 degrees cruising..
 
#32 ·
One thing I have noticed with the heat latley is the fan is on but I can't hear it unless the rpm's come up passed 2k.I have noticed the boost has been at 5-10 cruising while the fan is on also.My MPG have gone down to 14.5 and nothing has changed other than running the AC anytime I am in the truck.Which in the heat makes the fan run.

Today was a cool day no AC lie o meter is saying my average is 17.It is normally .5 high so I am getting 16.5

Just an observation.

Mike
 
#33 ·
i have noticed higher EGTS when its 90- 95 out during the day as opposed to around 80 degrees at night
 
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