Quote Originally Posted by mossaidis View Post
AFR will vary based on where you are taking the sample from. ratio can change just be moving your sampling location by a few feet.
It certainly shouldn't. If it does you have issues. Assuming all cylinders are running at the same AFR (they never do) you should be able to measure the same AFR at the exhaust port as you do at the collector or at the tail pipe. If you aren't then you most likely have an exhaust leak at some point in the stream.

Ignoring how real world airflow at speed on the track might affect the engine there should be minimal difference between the tune you see on the dyno and what you see on the track. Tuning is what dynos are used for... If they didn't provide repeatable results no one would use them. One of the most basic rules of tuning is to give the engine what it wants which means sometimes you have to step outside of the box to optimize a tune. Now that may mean that something is wrong with the engine package and you're compensating for it. But the dyno and test equipment, when properly calibrated and used, does not lie.