Thoughts on going from 5.4 to 5.0/Eco?
06-09-2014, 11:47 AM
#11
Senior Member
So i had my 5.4 screw on the highway yesterday...and surprisingly there was no wind. So I think to myself, hey this will be a good day to really see how it does on it's own, so I set the cruise at 70 mph and take off on a 200 mile trip on a flatter than a pancake highway.
The biggest thing that had me erked was the tranny..that poor truck shifts in and out of 6th so damn often, i'm afraid I'll shell the tranny out by 50,000 miles. It's clear this 5.4 was not meant to be on a 6 speed tranny, so I'm asking if anybody made the swap and thought it was worth it? Was there any increase in mpg? my lifetime average of granny style driving is 14.1 with 80% of my 31,000 miles highway.
My truck being paid off pays for a lot of gas, but the tranny thing i really can't live with. I rarely tow, i'm looking for something that's just going to run better. I've tried all types of tunes, air pressures, air filters. Oh, the dealer says it's normal and that the 5.4 is just "an old turd".
The biggest thing that had me erked was the tranny..that poor truck shifts in and out of 6th so damn often, i'm afraid I'll shell the tranny out by 50,000 miles. It's clear this 5.4 was not meant to be on a 6 speed tranny, so I'm asking if anybody made the swap and thought it was worth it? Was there any increase in mpg? my lifetime average of granny style driving is 14.1 with 80% of my 31,000 miles highway.
My truck being paid off pays for a lot of gas, but the tranny thing i really can't live with. I rarely tow, i'm looking for something that's just going to run better. I've tried all types of tunes, air pressures, air filters. Oh, the dealer says it's normal and that the 5.4 is just "an old turd".
06-09-2014, 11:58 AM
#12
Retired and loving it!
If you look at the torque curves for the 5.4 and the EB, you will see that the 5.4 is a long stroke V8 with the torque peak at 3,500 rpm. So, when it downshifts, it is just doing what it was designed to do --- get to 3,500 rpm where the power resides. (keep in mind that the 5.0's torque peak is WAY up there at 4,500 rpm!! --- take that for what you think it means, folks)......
Looking at the torque curve of the EB is a wondrous thing compared to the 5.4, and even the 5.0. The EB's curve goes straight up to about 2,100 rpm, then stays flat all the way to 4,500. 90% of the torque is available for that entire rpm range. The 5.4's curve looks like a mountain, the EB's like a high mountain plateau.
Looking at the torque curve of the EB is a wondrous thing compared to the 5.4, and even the 5.0. The EB's curve goes straight up to about 2,100 rpm, then stays flat all the way to 4,500. 90% of the torque is available for that entire rpm range. The 5.4's curve looks like a mountain, the EB's like a high mountain plateau.
06-09-2014, 12:10 PM
#13
Senior Member
Thread Starter
that's with me running custom tunes...5star and php
06-09-2014, 12:28 PM
#14
Senior Member
06-09-2014, 12:33 PM
#15
Senior Member
Thread Starter
lol...it's a 4x4...but i live in the flat as flat can be central kansas. I've always attributed it to wind, but the last few days the wind has been less than normal so that's why i'm shocked the truck was driving like this.
06-09-2014, 12:38 PM
#16
Senior Member
Maybe something is wrong as I run 5 star tunes and can hold 6th with my 4.6 3V.
06-09-2014, 12:40 PM
#17
Senior Member
Have you tried reloading your tune. Kinda like a hard reset.
06-09-2014, 12:46 PM
#18
Senior Member
If you want to see next to no downshifting while driving then the Ecoboost with 3.73 gears is your best choice...
I tow 7500lbs and while towing i lockout 6th gear and she will climb 85% of the hills in 5th with the cruise set between 60-65mph.
Go to your local dealer and take one for a test drive and find some hills to climb.. I'm willing to bet after the test drive you will be ready to sign!
I tow 7500lbs and while towing i lockout 6th gear and she will climb 85% of the hills in 5th with the cruise set between 60-65mph.
Go to your local dealer and take one for a test drive and find some hills to climb.. I'm willing to bet after the test drive you will be ready to sign!
06-09-2014, 12:50 PM
#19
Senior Member
My drive has lots of decent grades. I have had 3 5.4's. 1 03 F250 SC 4X4 3.73, 1 03 F150 Screw 4X4 3.73, and 08 Expedition EB 4X4 3.31. The best "performing" I thought was the F250 surprisingly. I heard they received a looser converter and it actually didn't do too bad. 11-12 mpg. The F150 had 305 70's and returned 11-12 mpg. Both of these would shift to 3rd on any decent hill. The Expedition was a gutless pig with the 3.31's even with the 6 speed auto. My 5.0 would walk off and leave it. Literally the wife and I got on an entrance ramp at the same time. By 70 mph I had put several truck lengths on it. All of my 5.4's were dependable and good towing motors. But, I say this without hesitation, the 5.0 is in a different league. I can look at dyno graphs all day long but the 5.0 has good power on the bottom end and gets a second wind about 3K. I have towed several times with it (including hauling the Expedition on a solid deck car hauler) and it just delivers. Best mpg before the level and mpg sucking Trail Grapplers was 21.9 on a summer trip. And with the stock tires it never hunted out of 6th on my drives on the interstate. Even with the Trails it will go to 5th on the more aggressive hills. The ECO is like a diesel. We have one in an Explorer Sport and it goes to 6th and just stays there. Great driving motor. Makes a vehicle feel "lighter" as throttle input versus vehicle reaction feels 1:1.
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k-stater88 (06-09-2014)
06-09-2014, 02:42 PM
#20
It would be cheaper and cooler imo to just supercharge the 5.4 the added 150 hp and torque should help it staying in 6th and it might actually help you mpgs. Or you could try changing the gearing in it too throw in some 4:10's in it might hurt mpgs though
Last edited by erasmo; 06-09-2014 at 02:47 PM.