2006, 4.6, 3.55, scab, 4x4 w towing package. Went from factory 17's and 31's to a much wider larger 33" tire and 20" rim. Now the truck doesnt want to hold overdrive on any of the hills it was able to before. Will a tuner be enough to make it as it was before or do I have to suck it up and get gears?

 

My suggestion is to get a VMP Tuned Xcal2 and than if thats not enough get the gears. The tuner will come in handy anyways when you make gear changes as well as to correct your speedometer.

www.VMPTUNING.com

 

that seems very weird. going up only 2" shouldn't have made that big of an effect.

with your motor, it would be most likely a 4.10 gearset for you. you'd get some nice performance and keep the highway RPM's down

 

Wheel weight went up too - significantly increasing rotational inertia

 

I agree, that sounds pretty harsh for a small increase in tire like that.

 

He's got a very sensitive assmeter, it can pick up very slight changes in performance.

Seriously though, he's got a 4.6L and 3.55s. It's not a good combination for a bigger wheel/tire package.

 

^^^ Not what I'd call an over-abundance of low-end torque to begin with.

Further degrade that with a combo of a 0.70 OD ratio +2" + add mass at wheel circumfernce = what he's experiencing.

 

True, I feel a v-8 truck should not have to come out of lockup in OD just to get over a mild hill. Very annoying for me to hear the motor keep coming in and out of OD when before I could make the same trip without going out of OD once. I wanted 3.73 but the dealer couldnt locate one with the other options I wanted, so I settled for 3.55's. Does the VTP tunes drasticially help low end TQ? I feel if I could just gain 20 FT/LB's or so I could keep it locked up

 

lets see the pics of the new setup

 

Working on getting the pics loaded tomorrow at work

 

You need gears, 4.30s and a tuner will make a big difference.

 

Since you have an 8.8 rear, a 4.30 gear is an option. IMHO thats a good gear for a 33 inch tire. Now I am only going by the math, not the actual experience. I am too cheap to buy the tires and gears up to this point.

 

Get a tuner, the 4.6l 2v has a lot of mid range torque missing.

 

I switched to 33's "285/70/17" recently and have the same thing going on. I wanted 3.55 and 4.6 for better hwy mpg. When I purchsed I had no intentions of running anything over a 265/70/17, but that has now changed. Killed my performance and lost 3mpg from the crappy stockers.

I am not shocked in the least. Hind site is I should have just gotten the 5.4, but I had my head in a hole when I bought this one.

If ford could ever get my ride issues straightened out, I planned on paying them to re-calibrate the computer. Have heard this could help a little,bit but is no replacement for torque.

Good luck.

On a side note, a guy I work with just turned 300k on his 4.6 and auto tranny. Makes me happy to hear. The best part is he does little to no maint.