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post #16 of (permalink) Old 07-30-2019 Thread Starter
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Originally Posted by JBert View Post
yep, size is the most important but the revs/mile does vary a little by brand, so to get the exact right number you can look up the exact tires . . . but it's probably within the tolerance of the settings available in the tuner anyway

my only other guess on the speedometer issue is that maybe the adjusted parameters aren't actually loaded correctly into the ECU -- on my tuner you have to adjust the parameters and then download the tune, if you only adjust the parameters it doesn't actually do anything (until you download the tune with the adjusted parameters)
Yeah that's how I have to do it. Reflash every time I change a setting. Previous owner didn't know why the speedo was off. The RPM matched what I found online, but it was still off with 4.10 selected, so since it was the same deal with my 01, I tried it with 4.30 and it was spot on.

2007 Mustang GT - 5-Speed, Airaid CAI, 4.10s
2001 Mustang GT "Mock 1" - 5-Speed, 03 Mach 1 Swap, 98 Cobra Intake Cam Swap, BBK CAI & Longtube Headers w/ H-Pipe, 4.10s 302 rwhp / 310 ft-lbs
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