Okay.. first I apologize if I have posted something that has already been answered.. I hate when people do that so I searched hard, but haven’t found my answer... this forum and the guys posting here are full of info.. awesome.

I am looking at buying a 2004 F250 5.4L V8 3.73 lmt slip FX4. But.. full after market conversion package.. lift kit oversized tires.. etc..

I am very concerned about mpg as I put on 15-20k / year.. but can’t own anything but a ford truck… I believe the 5.4L will get me the best mileage over the V10. I don't want a diesel.

So… this truck that has 4” suspension lift and 305s rather than the stock LT235… 31.7” to 32.8”

This forum has tons of info.. based on a different thread went here:
http://www.off-road.com/tools/gearcalc.html

looks like my 3.73 gear is now 3.6 this affect towing.. which is fine.. I tow a 3000# ski boat occasionally… no issue.

but.. the bigger tires throw off the speedo based on that site above also.. so I need to calculate the mpg differently based on traveling farther than my odometer indicates.. but the lower gear ration gets me better gas mileage right??

I guess my real question is what gas mileage I can expect. Either based on above details and expectations… or if someone out there has a similar truck and experience.

not sure if it makes much difference.. but the truck is a super crew, short box, 4speed Auto transimission

Thanks for any help...

 

Me driving the '02, (7.3L, 3.73, 4x4, 265-75 tires, CC, 6ft bed) at 70mph (2000rpm) consistantly gets 19 not towing. Towing at 70, or driving at 80 drops it to 15. Ya just ain't gonna get that mileage/power with a gasser, sorry.

There is a multiple thread discussion not to long ago on the 5.4L vs 6.8L mileage wise with this large of a truck.

Adrianspeeder

 

okay... I looked again and didn't find anything. can someone point me to the thread that will help.

I see the one call "quick question" but that's all PSDs... I am looking for info on the 5.4L

So.. Can anyone give me a quick update on what they are getting for MPG on the new 5.4L engines in a 250 or 350... I believe the engine changed in 04 from 16V to 32V.

also, has anyone seen their mpg increase after putting on larger tires since the effective gear ratio is smaller... taking into account your odometer is now off by a bit.

Thanks for any info...

 

I'll looky after I get back from class, but the tritons in the superdutys changed from a 2 to 3 valve per cylinder.

Adrianspeeder

 

oh yeah. my bad.. 24V not 32V.. got it confused with my Navigator.

 

Skip the BS from half ton owners and heres a useful thread with a lot of input from V10 owners.

https://www.f150online.com/forums/sh...d.php?t=259950

Adrianspeeder

 

You sure it's a 3:73 behind a 5.4 in a SD?

I can't imagine expecting very good MPG especially with a lift and even moreso towing. A neighbor has a 5.4 SD and his description of trying to tow with it makes it sound like it's something you only want to do in a pinch. On the other hand, I know of a super cherry 2002 5.4 F250 2 wheel drive that tows a trailer with a couple of bikes (custom and an old school Indian I believe it is) and they seem to like it just fine, and are actually selling it because they don't need a F250 for anything else and want to downsize.

 

i have an 06 ford f-250 5.4 l 4x2 gas and its crew short wheel base and 5 spd auto and i usually get 17-18 mpg and i am very satisfied with it

 

I've got the 2006 F250 5.4L 3.73 and I'm currently only getting 9.9-10 MPG.

You can see my gallery for my set up, but I haven't had the speedo recalibrated yet, but I am VERY hopeful that that number will go up.

Bill

 

If this truck is a conversion package, then the speedo and odometer should already be reprogrammed to match the larger tire size. The new 3V 5.4L has been doing better on fuel from the sounds of it than the older 2V models. Basically don't plan on more than 15mpg on a good day, and expect close to 10 or less towing. Due to the extra weight of the SD truck, plus a trailer it just doesn't have the low end grunt to pull without using more fuel.


A friend of mine has an 01 F250 5.4L with a 4" lift and 35s with 4.10 gears. Unloaded he gets around 12mpg with it, pulling a 16' trailer with an Explorer Sport he gets around 9mpg. Granted he does have a little bit of a heavy foot, and likes to tow at 75mph. Though the mileage doesn't go up that much when he slows down. Just remember that the 33s have a higher rolling resistance due to a larger rotating mass to get moving, as well as higher friction with the highway due to the width. The height is killing you as well in wind resistance. You're basically trying to move a 7000lb barn door down the road.

Overall I've been impressed with the 5.4L in my friends truck power wise and it wouldn't bother me to own one. He can keep pace with me for the most part, though throw a trailer on the back and I can walk all over him. Though hes always way out in front when we tow together, but I like towing at 70mph more since I take a big hit in mpgs over 70.