Man did I goof it up...diameter is 27"..lack of sleep will do that, but Mike I did read tonight to double check and the U7140 did state the calculation to be 20168..is this a misprint as I have not DL the new updates yet. Thanks Tom

Mike the instruction that came with my manual shows in two different places 20168

I have a U7140 Preditor and I did a parameter change on the Tire Revs for proper Speedometer range for a set of 18" Tires. I did as follows: took the 20168 and devided it by the tire diameter of 18" and came up with 1120 and entered that into the tune. I have since driven the car and I think its not ...

like you said just restore the oem tune back to the original car and put the tune back into the Preditor. When your ready to load to your car just run the tune again to your car

10 to 1 the Preditor is still in performance mode on the ecu and you can check by going into custom tune from the 93 octain tune your running. 2nd the .1 is correct meaning 10%. You could always go to a 91 octain and its not much difference.