Originally Posted by ByThaBay

I wouldn’t necessarily say that your tuner is wrong with respect to maf readings. It is true that under SOME conditions the air will be more turbulent with an aftermarket air intake than with the factory intake. The factory goes through great lengths to ensure the airflow has as little turbulence as possible and the result can be observed in the relatively smooth maf signals present in most stock applications.

With that said, an intake that produces more flow will in fact produce more power since the air mass consumed is larger and a larger amount of fuel will need to be added to hit the desired fuel targets. A good measurement without a dyno can be approximated by logging g/s of air consumed by the engine under identical conditions for comparison.

Ultimately a lower turbulence maf signal will produce a more accurate load calculation and that will produce a smoother ignition timing curve and the car will drive smoother than a high turbulence system. Each implementation has its drawbacks/benefits.