Here is the rundown. I have a 2002 5.4, 3.31's, 285/75/16, Superchips. I just put the tires and the tuner on the truck about a month ago. I have been monitoring my fuel mleage closely to see how much the tires and tuner affected me. I am wondering what everyone thinks about the results.....

Stock I was getting 13.5 to 14 MPG.

When driving the truck easy. No jumpin from lights and no hammering the gas to pass people, I get 14.9 MPG. I don't think that is too bad, especially having the 3.31's. That was 3 full tanks taking it right down until the low fuel light comes on.

Now here is the kicker. When driving the truck hard. Coming off lights hard and getting on it to pass, I am getting 14.8 MPG. Again 3 full tanks right down to the low fuel light.

Not sure if I will bother with a gear change now. I guess I will have to do some more research to figure out how 3.73's will affect the MPG. Does anyone have any suggestions on how I could possibly get some rough numbers before actually changing the gears?

 

Acceleration is NOT the primary factor in fuel mileage, in fact, it can be MORE EFFICIENT to get on the gas hard, in certian situations. The PRIMARY FACTOR, is how fast you drive. THAT ALONE affects fuel mileage more than any other factor. Slow down 10 mph, and see what that does to your 14.8mpg.

 

as I had posted in another thread:
First tank, I drove my normal way...= 16.04 MPG
Next tank, I lightened up my foot, didn't go over 1700 RPMs (@ 65MPH) on the highway = 17.76 MPG

An easier right foot is the BEST mileage mod

 

Investing all the time and money to go from 3.31's to 3.73's would not be worth it in my opinion.

 

i went from 13-14mpg highway to now 22.. i changed back to platinum plugs. and put my 75mm BBK throttle body on and got my speedo closer to where it should be. im going to have to put it on a dyno to be sure. but i think its closer now. and im gettin 18 in dallas traffic and 21-22 highway doing 70-75mph

 

That's just it, my gears are hurting my light foot driving!!!! If you sit down and think about it...... If I can gain 2 MPG by going to 3.73's, the gears would pay for themselves in a years time. That's 50 extra miles per tank. Figure it out from there. If I won't gain 2 MPG by changing gears...then it won't be worth it. I am just trying to get a ballpark idea of what I would gain. There are just so many variables, that I won't figure it out until I change gears.

There are not many people with 3.31's so it won't be easy for me to figure it out. Going from 3.55 to 4.10 is no where near the same as going from 3.31 to 3.73.

See what you did....Now i'm rambling....

 

If you have a 4x2, I would sugggest going with the 3.73's, depending on how tall your tires are, do a search on 4.10's, I can't find it now, but there was a really informative thread from 1999 about the mileage and performance gains.

 

I have a 4X4 with 33's. I will look for that thread. Thank you.

 

I dont think you are right on that chester. When you floor it, the computer demands more fuel in the mix, ergo you are burning more gas............

Drive by the tachometer if you want to get good gas mileage