I did some searching and still have not got any real concrete answers. I have gone from an A4 to M6 and my MPH is off. I know about the taking measurements by doing roll-out. Question is I have a 98 Camaro and its not even an option to put in a tire size and gear ratio. Do I have to manually do it everytime through chaning the VSS per mile?
Here is a screen shot of what I am talking about. Thanks