I multiply my odometer and speedometer readings by 1.031 to compensate for the increase in tire circumference going from 195/60/R15 to 225/45/R17.
Go here to calculate the difference, its so useful, and quick.
http://www.miata.net/garage/tirecalc.html
I did a 5 spd. swap, but the final drive ratio should be identical to a manual car. 5th is a bit shorter than O/D on the auto, I’m doing 3350rpms at 120km/h. Seems a bit too high to me, that’s halfway to redline, cruising on the highway…
I wanna scan my ECU, I have to save up some money to pay off debts and then buy that consult cable and software. Debts are obviously car related lol.