I had the same problem. I emailed the developers and this was the reply which works just fine for me:
Hello,
Thanks for the logs.
This is some kind of standard issue for Mustang - PCM tune. FORScan recognizes vehicles using information stored in PCM's VID block, but majorioty of tunes...
Absolutely correct. HOWEVER, the Roush TVS 670hp tune may still be managing torque/power through timing or other methods than just the "nannies."
My 1/8 ET, MPH & 60' times are better across the board on 285/35/20 (27.9" diameter) street tires than on the 315/35/17 (25.9") drag radial tires...
It's impossible to compare back and forth my speedometer reading to GPS speed reading during a pass at the dragstrip.
My main goal is to have the the correct diameter value so the electronic controls do not think the rear wheels are spinning and start to limit torque and/or power when...
I want to change my as-built tire diameter hex data value for my Mickey Thompson ET Street S/S 315/35/17 drag radials. When I am at the drag strip I lower the tire pressure to 17psi. I wonder how much additional "squishing" factor there might be over the 96.7% circumference figure Ford is using...
Ahhh, now we are getting somewhere. The Whipple flare tool is $275, that's certainly better than $400.
Thank you for the contributions.
BTW, what does "BCM" stand for?
I called Roush (I have the Roush TVS) yesterday and spoke with their technical department and they recommended I get a tuner from American Muscle or CJs, but it looks like they are all @ $400.
I don't really want to spend that much just to be able to change the tire diameter parameters at...
How can I cheaply change the tire diameter / revolutions per mile parameters in the ECU/tune for tires that are different in size that stock?
I have a rear set of drag radials and I would like to easily change the Parameters as I will be swapping them at least monthly.