I'm sure all you guys have gone over this a million times but I'm new here and hope someone can help me. Bought a new 2006 sd 250 lariat super cab 4x4 in Sept. My first deisel. Has 3.73 limited slip rear end ratio and 8' bed ,Automatic, 10000gvw. I have almost 8000 miles on it now. I probally have 2000 miles of highway towing a
5000# stock trailer. Heres the big question what should I expect for mpg on the
2006 equipped the way mine is. Friends with 2004's say 16-18mpg all day everyday and 20+ on the highway. I've had it on several trips (not towing)
and the best I get is 18ish, all day everyday the best I do is 12-13. I do not
horse the truck at all. Is the 2006 de tuned so bad that the mileage is suffering
from past years? If its detuning will a mild chip help? Or do I have an engine
problem? So far the dealer is no help because gas mileage is not a valid issue
to them without something else obviously wrong. What are the rest of you guys
seeing?
Thanx great forum

Jeff

 

I have a 2005 F350 Crew s/b and 3.73s. I am getting hand calc 14 - 15 combined driving, 18 - 22 on highway trips. I was getting more like 13, 18 but have modified driving style a bit. Also, I think now at 10,000 miles so breaking in. Normally city and short drives, try not revving much over 2000 to 2100 rpm unless you have to. Also, modify acceleration so that you are staying in a higher gear more. I know this is hard, cause they go so good. On highway mileage, tire pressure at recomended or close will increase mileage a bit. I did two seperate trips same weather, load, 900 M round, with tire pressure only difference. It was almost 2 mpg. Same cruise speeds. Also, I have found not using the cruise improves mileage a bit, keeping the speed below 70 mph, I think 65 mph is the sweet spot.

Mod, please bump to 6.0 forum.

 

Thankyou ,after I wrote it I realized I had it in the wrong forum but didn't know how to change it. What tires do you have at what pressure? I'm running the stock Contitrac Tr's on 18" rims at 60psi. I'm not happy with them for winter driving at all. But it seems hard to find any snow tires made for the 18" rim.

 

Thread moved

 

06 6.0 CC 4X4 LB gets 14/16 on Hwy. 10/11 towing big trailer. It looks like your about normal. I would take anyones "word" that they get 22/23 MPG with a grain of Salt!!

 

Moby - I have hand calc mileage for 11k miles. All my hwy are over 19, with limited cruise and proper tire pressure, less than 70 mph. All trips on summer fuel or conditioned winter are over 21, best is 22.9. If you don't believe me, I don't care. I was trying to help the guy.
When I drive hard, pass lots, accelerate hard all the time, cruise at 75, mileage goes down to 16 on the hwy. Don't drive hard now, older and more responsible.
JDR - I would run 65 psi front, 70 psi rear, 75 psi rear with camper. This will help mileage but I think the sail effect is your bigger problem. My old 2000 sd with camper was a 5.4, it was in the 9 mpg most times. Just had to grin and bare it, afterall you are goin campin!

 

Regarding the "grain of salt" thing...

It is very possible to achieve over 20 mpg with a 6.0L. Before I did *anything* to my 2004 2wd F250 SC XL (complete with crank windows and no tilt) with M6OD, I got a bit over 20 mpg at 70-75 mph. That was hand calculated with a fuel-in-the-neck fillup each time.

Driving habits make a huge difference - if I shift at 1500 rpm or less vs 2000 rpm, I increase my economy by 1.5-2 mpg. If I drive it like I stole it, I lose 3-4 mpg.

I have a 60 HP SCT flash, 3.08 RAR and 235-85-16s and now get at 76-77 mph (1900 rpm) 24 mpg. Not guesstimated, actually driven and calculated.

To and from work in Dearborn, MI (24 miles each way) with a lot of stop and go I get 18-19 mpg in the winter time. Again, if I beat the **** out of it I will get less.

Anyway, even a sanely driven automatic 3.73 can achieve results in the 20s. I *would* question someone with the heaviest combo like a F350 4WD dually auto/4.30s getting 24 mpg....

I even borrowed a friend's 04 Excursion 2WD for a long trip and did the 100 hp SCT flash. From Canton, MI to Hatfield, PA (about 600 miles), some local rural driving (100 miles) and then the return trip, I went 889 miles on a 42 gallon fill (44 gal tank) before I stopped in Bellefonte, PA on I80.

That was achieved without cruise, driving a steady 70 mph (except 80 mph for the 50 miles in Michigan to avoid being run over).

BillWoeb

 

I've got 2 6.0s a 06 & a 05 neither one has ever seen 18 MPG One a Reg Cab XL model both are 4X4s Autos, Rarely do they see interststes Hwys. The local speed limit is 55 MPH, so the trucks rarely see anything over 65 MPH. They average around 15.5 MPG. Not one of my friends that have stock 6.0s get that good. Most envy my fuel mileage. None with programmers get better than 14 MPG!!

 

I just averaged my first 32 tanks of fuel and came up with 13.3 mpg. Approx 8 tanks were pulling a light duty tandem axle with a couple of job boxes on them. I think driving speed has a big affect on milage. On non Interstate highways I have gotten into the 15 range @ 65-75 mph but driving across Montana and North Dakota in 0 degree temps I got about 11 @ 75-85 mph. General home and around town use seems to be about 13 mpg. I keep hearing that the motor is "broke in" @ 30 to 40 thousand miles and the milage is better. Right now it is just broke (See my thread 6.0 died). Please note all the averages were before exaust and intake were installed. The one tank I calculated after was 11.2 but it was into a very strong headwind across Wyoming and there is a lot of weight in it right now.

 

My '06 F250 FX4 CC SB 3.73 completely stock tells me I get 21.5 at 65mph cruise control on fairly flat ground in FL. I reset the lie-o-meter while cruising at 60 and after about 5 miles it had averaged almost 24. I use the grey bottle of Diesel Kleen from Walmart and run non-premium diesel. Only have 4000 miles on the truck.

Regular driving 2 miles to work kills it. Goes to just over 13mpg average. I drive it easy except for getting on it at least once/day.

Towing my 7x16 tandem enclosed trailer at about 4500# I get 12mpg at 75mph and 16 if I slow to 60-65mph.

 

My 04 6.0 PSD DRW gets about 13ish in town and about 10ish pulling a 33 foot 10,000lbs 5th wheel doing about 78 to 80 mph with the A/C on. My next trip I'm going to try and stay between 70 and 75mph and we'll see if it makes a difference.

 

Dogs, I bet for every 10mph you slow down you get 10-15% better mpg.