2007 Sport Trac V8 - MPG

[AJdude]

I have a 2007 Sport Trac with a 4.6L V8.

Currently have oversized tires (185/60/18)(nitto dune grappler)

I am currently getting about 13MPG city

How can I increase this? Maybe a chip?

Thanks!!!

 

[GSU4x4]

That size can't be right, is it? That seems very small maybe 285 not 185 cause I have 265/70r16 General Grabber AT2's on mine. Anyways the bigger tires are going to kill your mileage, I have the same truck, 07 V8 4x4 and when I baby it around I get about 14-15 city. I'm looking into getting a programmer for mine to see if I can increase the mileage, I've done some searching on this forum and it seems like Hypertech has helped some people and didn't help others. I'm planning on getting a Hypertech when I get the Truxxx lift kit and slightly bigger tires to help with the mileage.

 

[calahan#2211]

A 285/60/18 has a running diameter of 31.5" as opposed to the original designed diameter of 30". That is about a 5% change in gearing and multiplication of the torque. You have two things working against you, the taller gearing and mostly the added weight. About the only thing you can do is correct the gearing multiplication or maybe go even a bit shorter. Trying to get a heavy vehicle ( mine is a 2wd and weighs 4,800 lbs ) and a heavier tire ( with less torque multiplication ) takes more fuel than carrying it down the road at a constant speed. I'm thinking you may want to go to at least a 3.73 gear ratio in the diffs. Actually a change to 3.90's ( 10% ) would probably work best. The problem is the you may not have a vast array of choices for the front diff. You'll have to do a little research to see what's available. A k/n drop in air cleaner may help a bit. I know it doesn't sound like the simple solution, but is most likely the only thing that will make a real difference. With the shorter gearing you might notice a slight change in highway mileage but would be pretty negligible.

 

[AJdude]

That size can't be right, is it? That seems very small maybe 285 not 185 cause I have 265/70r16 General Grabber AT2's on mine. Anyways the bigger tires are going to kill your mileage, I have the same truck, 07 V8 4x4 and when I baby it around I get about 14-15 city. I'm looking into getting a programmer for mine to see if I can increase the mileage, I've done some searching on this forum and it seems like Hypertech has helped some people and didn't help others. I'm planning on getting a Hypertech when I get the Truxxx lift kit and slightly bigger tires to help with the mileage.

Ya that was a typo! haha 285 is correct!!!!

Im also considering getting a lift for it, Im gonna look at the Truxxx one. Thanks!