I bought an 03 F150 a few months ago and absolutely love it. Performance wise, its a stock 4.6 4 wheel drive and single cab. Body wise, it has the black step bars and black wheels wrapped with bfg mud terrains (equivalent to 31s in size). They suck for daily driving and thats what I bought the truck for. I love the size of the tires, but I'm sure they're making gas mileage bad. The only time it sees more than 2300 rpms is climbing a hill or something. Is there anything I can do to increase the gas mileage? I've heard those programmers are good for this, but I have no experience with anything like that.


Also, I want to run true duals with dynomax bullets straight out the back, or a single in with a y pipe splitting it. No turn downs as I think it looks bad and is too loud in the cab. Anyone have videos of this? Any help is appreciated. I'll have pictures up asap also.

 

Welcome! Something to consider, if your tires are taller than the stock tires and if the speedometer was not recalibrated, your mileage is off.

 

I just thought about that. It wasn't recalibrated. Actually got pulled over a while back. Speedo said 70, the trooper said he clocked me at 79. He believed me and didn't write me a ticket. So do you mean that I'm actually getting better gas mileage than I think just because my speedo is off?

 

Yes you're traveling faster than you think and a larger tire covers more mileage. So therefore, you would get "better" to the naked eye, you need to figure out the difference in tire size from what stock was, to what you're running and always do 5% or whatever it is before doing any kind of calculations. Tuners are very good, I'm fond of Xcal 3 from VMPtuning.com. They do good work though, tuners are well worth the money, they help you're computer know whats going on, take full advantage of mods and what not. What are you looking to get out of your exhaust? Any gains or just looks?

 

bigger tires = worse gas mileage because its more weight to hall, i dont see how at all it could help.

The true duals will help with your economy though, my '04 5.4 does 16.2mpg average with its duals.

 

Not true, if the computer isn't tuned it will think it's factory ratio. So you personally will think you're getting better gsa mileage.

That's cause you drive like a grandma.

 

You cannot re-program different revolution mass of a larger tire, Wheels and tires are non programmable... therefore gas mileage will not be that great if the revolution mass is increased.

 

Yes you can, when you get a tuner.

 

All that does is calibrate your speedometer to give an accurate MPH reading. That does not help your economy, it just tells you your accurate speed.

 

Exactly, but it can possibly give you better gas mileage.

 

A bigger, heavier than stock tire helping mileage?

 

More horsepower and torque=easier to push that bigger, heavier than stock tire...

 

So you're saying that with a tune that you will get more mileage with a bigger, heavier tire vs. a tune with a smaller, lighter tire?

I have a VMP custom tuned XCal3 with a stock 17", 30.7" tall and when I switched to a smaller 29.7" tall on a 20" rim, I felt a noticeable power increase. As for mileage, I can't be sure because I usually drive it like I stole it.

 

Dude, no it wont. You cannot program for a wheels weight mass, and rotational per mile numbers. You can get some performance out of custom tuning, and calibrate your speedo for the larger tires, but the fact of the matter is, bigger wheels & tires will not rotate as quick as stock tires will, therefore, minor economy decrease.

 

. No I never said that.