5.4 triton mileage improvement?

dumprat

Adventurer
Has anybody had any luck improving the mileage on a 5.4 in an F20 orF350? I had an 04 extra cab and it did ok. 16 or better. Most claim this is impossible. I am looking at an F350 crew cab short box and would like to get the best mileage I can out of it.

No I will not buy a diesel. Too many problems with fuel availablity and cold temps in the places I like to go.

Thanks
 

toylandcruiser

Expedition Leader
Has anybody had any luck improving the mileage on a 5.4 in an F20 orF350? I had an 04 extra cab and it did ok. 16 or better. Most claim this is impossible. I am looking at an F350 crew cab short box and would like to get the best mileage I can out of it.

No I will not buy a diesel. Too many problems with fuel availablity and cold temps in the places I like to go.

Thanks
I wonder how Russians get away with running so many diesel powered vehicles in the winter?


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thethePete

Explorer
Yeah, I can't picture a lot of places where you can get gas but not diesel, and that aside, cold temps aren't an actual issue unless you're leaving it shut off for more than 24h in -40*, and even then, glow plugs and a strong starting system will still get it running.

But that aside, you may be better looking at the v10 if you're looking at going F350. Mileage will be similar and it'll handle the loads a little better. Double digit mileage while loaded with a gasser engine is optimistic at best.
 

Buliwyf

Viking with a Hammer
Gas is $2.35 a gallon. Get your truck and enjoy it. Hauling my bike from Mid Ohio to Deals Gap costs: $87.48 at the worst.

Call us back when it's $4.90. Most of my cross country trips, fuel is a negligible cost. Less than food. Less than decent charter tours even. If you use your truck for local use, nothing will give good mileage. On the freeway is the only place where I spend money on fuel and can save a little on fuel. And it's pretty weak. Not the major issue Expo makes it out to be.

But with the 5.4L:
-don't fear the gear. 4.30's or better. RPM helps as much as it hurts.
-skinny small tires, don't you dare go over 34". (295/70 r17 for example)
-avoid mud terrains if you live where there is no mud.
-stay low. No lifts.
-stay light. Avoid the poser winch bumpers.
-aero. Do not remove the front lower plastic air dam thing. Let it drag on rocks, beat on it, use it as a feeler. If it drags, so will your axle. No lights over the cab.
-keep the engine fresh.
-lube your hubs and service your axles and xfer case often.
-stay off the gas pedal on flat accel, but don't let the 5.4 lug up hills. The 5.4L burns more fuel if you baby it up hills. Stomp on it! Get up to speed and keep her there. The 5.4 likes steady speeds and higher RPM's. No soccer mom driving.
-replace your brakes with loaded rebuilt Ford Raybestos calipers. Fords are known for dragging brakes around 100k. (often seen in other fullsizes though) Replace the pins as well. Even if you think your calipers are fine. I use loaded calipers for every brake job I do on Superdutys. Has been working really well. No more pad rotor slaps. Easy, easy, way to make a truck feel new again.
-fill the tires up. Yeah, I know it's stiff.
-check your ball joints and tie rods. Floppy steering hurts mileage. Toe out is the debil.
-crew cab long box. Because potato.
 
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camper357

Observer
What year are you looking at? 2005 and up f250 and f350 have the 3v 5.4, a 5 speed automatic, and a coil over up front. I had a 2 valve 5.4 and a 3 valve 5.4 , both f150's, and found the 3v was slightly better on gas. I don't have experience with the 5 speed auto, but I think it would be a step in the right direction.
 

Buliwyf

Viking with a Hammer
The older 2v 5.4L is superior IMO, but the 3v is more powerful. The 3v has a retarded cam phaser setup. Sounds like a disgraceful blown topend all the time. But the newer 2005+ truck is better everywhere else. The 5r110 transmission is good to go.
 

thethePete

Explorer
^ If it sounds like a blown top end, it needs phasers. Phasers/tensioners/solenoids as well as the original multi-piece spark plugs are the weakpoints on the 3v. As long as the oil changes have been kept up you should be alright for the timing chain issues, but they all fail eventually. And when you're in there, do all 3. I've seen people only do phasers or solenoids and they always end up going back in to do the other two. If the plugs haven't been done yet, replace them with the updated 1 piece plugs. Get the engine hot, do one bank, run the piss out of it for a minute or two to get it hot again and do the other bank. That's your best chance for not breaking a plug off in the cylinder. And if you do, it's not a god-awful job to remove the rest of the plug, but you will need the special tool.

5R110 is one of the strongest trannies on the market. It isn't as robust as the Allison, but it'll hold more power.
 

SportsmanJake

Adventurer
-stay off the gas pedal on flat accel, but don't let the 5.4 lug up hills. The 5.4L burns more fuel if you baby it up hills. Stomp on it! Get up to speed and keep her there. The 5.4 likes steady speeds and higher RPM's. No soccer mom driving.
You seem to know a good deal about the 5.4. Can you go into depth a bit more about the RPM in relation to fuel efficiency?
When driving on the interstate, I try to keep it around 65, which is around 1800 RPM. When in hilly terrain, should I try to keep the RPMs down? I always just assumed a lower RPM = less gasoline consumption. Mine is a 2v with a 3.7 gear ratio and 285/75r16 tires by the way.



-lube your hubs and service your axles and xfer case often.
I don't think I have ever lubed anything on my truck. Where should I start?

Thanks
 

advkid

New member
Quote Originally Posted by Buliwyf View Post

-stay off the gas pedal on flat accel, but don't let the 5.4 lug up hills. The 5.4L burns more fuel if you baby it up hills. Stomp on it! Get up to speed and keep her there. The 5.4 likes steady speeds and higher RPM's. No soccer mom driving.


I have found this to be true also any long grades I drop it out of OD in my 05 f150 5.4 and it helps a lot they hate to "lug"
 

dumprat

Adventurer
We took my fathers new to him 08 super duty out yesterday. 16L/100kms or 17.6 MPG.

Not bad by any stretch but it is absolutely stock. My thoughts are one could improve mileage with better quality tires, deeper rear end gears, delete of the catalytic converter, and larger air filter.

I was also thinking headers may help and eliminate the broken exhaust stud problem I had on my 04.
 

BushHead

Adventurer
I did notice a slight increase in gas mileage in my 5.4 when I installed a aftermarket exhaust, but I hear some do some don't.
 

402xjeeper

Observer
I had good luck with a hypertext max energy programmer on my 5.4s, and my v-10 excursion. On an f-350 a v-and a 5.4 are similar as far as mpg, both like to spin more rpms than you would think, match your ratio to planned tire size .
 

Buliwyf

Viking with a Hammer
We took my fathers new to him 08 super duty out yesterday. 16L/100kms or 17.6 MPG.

Not bad by any stretch but it is absolutely stock. My thoughts are one could improve mileage with better quality tires, deeper rear end gears, delete of the catalytic converter, and larger air filter.

I was also thinking headers may help and eliminate the broken exhaust stud problem I had on my 04.
I dumped my exhaust out in front of the right rear tire with a shorter Thrush muffler and a 45 turn. A hanger is added to a hole on the rear spring front mount.

No more hitting the exhaust on the ground when backing into a ditch to load bikes and wheelers. That's one of the things that breaks the manifolds. Weird that the force can travel up a flexy exhaust that far.
 
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