Or download a G-meter app, - that works off the accelerometer chip, not GPS.
Place the G-meter near your tach, - when the G-meter drops, you just passed your shift point .
Don't be surprised if the shift point is different in every gear .
Exactly the type of thing I was referring to. But this is not quite right. You need the intersect point of the two gears.
"If you can" you want the curve in RPM, not MPH as the example curve I posted. But you can "diddle" it once again, with gear ratios to figure RPM vs MPH.
