Well since I put the 35s on, I am getting 10.5 mpg consistently no matter how I drive... I have a 4.6l 2wd 2003. I just dropped a fully rebuilt 4.6 in and it didn't change the mpg at all... But it needed to be done because my valve seals were leaking, had a rod knock, and many other little issues. But it is to the point of possibly having to park the truck and get a car.... .... I've been trying to think of what I can do to bring up the mpg without getting smaller tires and then I saw something about gearing and it hit me... I forgot to regear!!! Now, I was considering 4.56s since I have 35s, but since I would like to get 38s later on I am leaning towards 4.88s. Honestly, do you think it is possible that I can get 13-14 mpg if I regear? Or should I do 4.56s and get 33s? (I have a spare set of used 33s at home)
For best mpgs... 31s...3.55-3.73 33s...4.10s 35s...4.56s 37s+...4.88s That's for mostly city and some hwy driving and if you tow. If you do more hwy driving, then bump the gears down one. Since you are 2wd you only have to do the rear axle (you don't have a front axle). So price wise you are looking at like 600-700 bucks max with parts. I have 4.56s with 35s and I'm getting 13 at best with a 5.4. Last question... how are you gonna fit 38s on a 2wd?
Thank you for the input! 4.56s it is! Eventually I want to straight axle it and actually convert it to 4wd. If I don't go that route then I'll do a 7.5" fabtech with a 3" body lift, but that wont be for a while.
Buy jarretts lift, 7.5" fabtech with 2 spacers and shackles I believe. But you'll have to wait another 2.5 years for him to put his. Mid travel on Sent from my iPad using Tapatalk - now Free
Gears will definitely help with your mpgs. Like said, I think with the 35s 4.56 will be yout best choice. I would do those first if its really going to be a good while before you get to 38s. Idk, what you're running for a lift, but you should go ahead and through a fabtech 7.5'' lift on there and see if you even want to go higher. Also I found this vid a while back where this guy is supposedly getting 25 mps in a 98 4.6. Same gen f150. Granted yours is lifted so it might be as great an increase, but it might be worth trying a few of these things. Mods are in the description. Just some ideas. PART 1 ,F150 Gets 25 mpg highway - YouTube
you need to Taylor, I got 4.11s with 35s and Ive got good power, mileage...well...its suffered some but worth it haha 4.56s would have put my highway rpms too high for my liking and left me with really bad mpgs, however the 3.55s I had previously still got me bad mpgs due to it downshifting all the time just to keep my power up on the highway. but was sooooooo slow when aceelerating. also, while your at it....add a locker.
I would love to buy his lift haha but I have seen that video before and have been meaning to look it up. Now I'm getting a lot of mixed opinions between 4.56s and 4.11s... Is there really that much of a difference between the two? I don't do a lot of highway driving, but I do drive some, so I am worried that if I go 4.56s that I will get terrible mpgs there, but 4.11s almost sound to be too little of an increase for me to really see a difference. I average between 40-50 mph daily driving, currently at 50 mph my rpms rest at about 1,200. I have heard that the "optimal" rpms that burn the fuel most efficiently is at about 2000 when at 60-65 mph and right now I am hitting 1,500 at 65. This is something my grandfather has been telling me for years, it seems to make sense to me. With that being said, I am kind of still leaning towards 4.11s for now, I was leaning towards 4.56s because I want to go with 38s down the road, but may wait for that. I have been doing a fair amount of research, but lately have been side tracked as my girlfriend just bought her first TJ so I have been researching those like there's no tomorrow!
4.56s at the least. I honestly wish I had got 4.88s in my old green truck back when I had it. 4.56s for sure Sent from my SCH-L710 using Tapatalk 2
A little background info on myself, I work as a general service tech at a Ford dealership so I thought I'd ask a couple of the lead techs here their opinion about regearing. I guess I should have been a little more specific with you guys, but I am looking to get better mpg out of regearing and not performance. Each one of these guys said that I need to go with a LOWER gear ratio, like 3.08s as opposed to a higher ratio like 4.10s or 4.56s, so that my rpms will stay lower across the board, in return burning less fuel=better mpg. I understand that my low end power would suffer, but I baby my truck anyways and haven't had it off road in a long time. Their logic made sense to me that a higher gear ratio would put my rpms at say 60 mph up to around 2800-3000... I am going to try and basically start building my truck for better gas mileage as I am traveling for school more so this semester than previous. Any other input on this information is greatly appreciated! Thank you guys for your help so far!
Lower gears you'll have absolutely no low end power and it's gonna be far worse on mpg cause your truck is gonna have to jump rpms to make the power it needs to do anything to move with low gears like that. What those techs aren't thinking about is your big tires. That changes everything.
