Hey guys, I don't post here much but I have been lurking around for while.

First off, I know these trucks don't get anywhere near good MPG, I bought it for towing, but I feel like I might be able to do better than 8....

I'm running an 8in lift with 38/15.5/16.5 Swamper TSL's. The truck was regeared for the bigger tires by Ford. The truck also has a throttle body spacer (it was bought with it). I'm currently getting 8.1MPG and want to try and bump it up even a little bit. Double digits would be very nice.

Any recommendation on bumping it up? I konw smaller tires will help, but how much smaller. Just going to a 37/13.5, will that be enough? Also I know there is a 5 star group buy right now, will that programmer help a little?

Thanks guys

 

Need more info:

What year is your truck?

Are you talkin 8mpg in town? Highway? Towing?
I would think 8mpg in town with 38's is probably pretty darn good. You should consider yourself fortunate.

You mentioned that you bought the truck for towing. What gears are you running in your truck and how much weight are towing? You gotta be severely limiting the towing capabilities of your truck with those tires.

FYI - I got about 9-10mpg in town with an all stock 3v V10 F350. I get about 11 now with the 5 Star tuner.

 

Get rid of the tires and lift and you will get the increase your looking for. Lift and tires look cool but your paying the price. I get 12-14 combined city/hwy driving mine like I stole it and 8-10 towing with 285/75/16's. I keep mine smaller for when I eventually get me a nice gooseneck trailer and to retain something decent for mileage.

 

2001

I get 8mpg both in the city and on the highway

Gears are 4.56's in the rear

 

Should be at least 4.88s with those tires. To me though 8 mpg around town isn't too bad with your setup. If your geared properly you should be able to pull 12 on a flat highway. A good tune would help the truck out but I don't know how much of a mpg increase you'll get with your setup. Any increase you get will probably be from premium fuel and strictly highway.

 

go down to a 37"s tire with a more street biased tread pattern...

as stated ur gearing still isnt tall enuf to get u in the sweet spot, the tires are to big...

p.s. i like ur pics gives me a good idea of what my truck's rear end will look like when i finaly get my 08 tailgate project done..

 

hi, have you had the comp. reprogarmed for the size tire you have ?? your odometer maybe off . also you have to pay to play ,cool truck, barry

 

Get that lumber out the back and you should pick up a few mpg's!! LOL, just kidding, get a tuner from 5-Star first.

 

Very good point I forgot about that. If you have a decent GPS you can tell fairly accuratly how close your odometer and speedo is.

 

You can also do it the old fashioned way. Drive down the interstate from one mile post to the next. Divide the number of seconds it takes into 3600 and the result is your speed in mph. For instance, if it takes exactly 60 seconds, the result is 60 mph.

So if you maintain what your speedometer says is 60 mph, you'll see how far off you are.....

 

I know since it has gotten cold this year my v10 has become a pig in the summer it was good

 

A lot of great replies so far.
A Ford Superduty truck has the air flow dynamics of a cinder block.....your would be cinder blocks that have been stacked a few high.
The increased diameter of the tires and the tread width greatly increases your tires rolling resistance.
The rear end ratio could be a little deeper to off set the tire size.
And as noted if the speedometer and odometer have not been recalabrated to the new tire diameter there would be a large percentage of variation in the figures needed to do a little calculations.
The colder weather will also hurt the mileage, but I assume the mileage figures you gave are pretty much a standard you have been getting, not just seasonal?
If the truck is of the 2V vintage engine there are a few mods that could help with the power performance, including exhaust, programmer from 5 Star and a few more that others can mention.
So the only other item I can see to recommend is push your tow/haul side view mirrors in towards the truck, rather than the extended position. Maybe it will cut down on side wind resistance...or not.
Great looking truck!!
Happy Holidays