Thread: Air flow meters

A couple more references.

3rd° Tech Tips~MAF Screen Removal
That is a good one.
[ame=http://forums.audiworld.com/showthread.php't=2165605]G70 Mass Air Flow (MAF) sensor and MAF screen function - AudiWorld Forums[/ame]

Regards Philip A

PhillipA and others are 100% correct. R&D people call the "mesh" a "laminarisation screen". It makes the flow nice and uniform.

A general rule of thumb is that if you have a straight section of duct 7x the duct diameter long upstream then you will still have a uniform velocity profile. However the screen will still flatten out the velocity profile more than no screen.

Many engines will have intake ducting which will operate in the laminar regime at low revs, then become turbulent as revs increase.

MAF or AFMs are made to a price point, so they are not completely accurate. Removing the Mesh would likely make very little difference at WOT, but a fair bit of difference to the mixture and emissions at low revs (whether you can notice it or not without an EGT and emissions measurement gear is another matter)