I have a Bully Dog power module that is several years old. It does not address my over size tires / wheels.

Looking for a chip / module that will let my engine know what my 24.5" rims and wheels are doing.

I just found the iTSX and watched a couple of videos. Is it just a gadget for my iPhone, or is it a good instrument for my truck?

My next module, I want it to help my transmission and engine with my over size wheels.

 

Because the iTSX plugs into the OBDII port, I would think that it could display speed. Probably even has the capability to recalculate for taller tires and/or gears. It's not the wheel size that matters, its the OD of the tire, or revolutions per mile. Which tire rotates more, a 42 inch tire on a 24.5 inch wheel, or a 42 inch tire on an 18 inch wheel? Neither, they have the same revs per mile.

It looks pretty cool, I'd be curious to see real world results.

 

None of the SCT products are going to change your speedo for your oversize tires, but what it will do is change the shift points based on revs per mile and tune the transmission accordingly.

In order to change the speedo you're going to need to do it with AutoEnginuity, or a superlift truspeed. Ford garage can also do it with IDS.

There are many more reasons why upgrading is a good idea. The bullydog is one of those generic "programmers" which means your timing is erratic (spraying fuel way outside the bowl of the piston) which jacks cylinder pressures through the roof (cause 6.0's need more reasons to blow headgaskets right?), they also do not tune the transmission what so ever (other than jacking line pressure). A custom tuned SCT will run cicrles around a bullydog truck and will be safer for your engine and trans in doing so.

 

SCT Flash Tuner Programmer 6.0 Ford Powerstroke Diesel | eBay

How about this product?

Is this a better product than the one that uses my iPhone, the iTSX?

 

It's up to you... The TSX was notorious for issues with the screens not working and such. The X3 is just a handheld programmer, no gauge setup. Both will hold the same tunes, so as far as tuning is concerned, either is fine.