Something different from what I’m normally testing, a BMW part. Inlet pipes for the BMW E92 335i N54 3.0L engine.
For those wondering, at 28″ the higher flowing pipe has approximately 44% more CFM passing through it for the same pressure drop. A good example of how subtle design differences can greatly affect airflow.
Some additional photos comparing the two pipes and their shapes.
Adding a chart with extrapolated pressure drop information out to 350 CFM based off a least squares fit to the measured system data.
And some additional airflow testing of a pair of aftermarket options, one from MMP and the other VTT.