Bumper? Not talking about the CSL bumper hole intake, I am talking about the headlight intake you posted vs our tiny oem intake.
The e46 CSL bumper intake, is pretty much on par with our oem intake hole. Oh and even the CSL bumper hole intake doesn't do the 90 degree corner flow.
Not sure what your looking at, but it's not chalk and cheese, the holes were talking about are about 30 percent compared to the headlight hole intake that you posted, that's what I was and have been referring to all along. Nothing to do with the CSL placement of the iat sensor, thats a completely different subject.
Please post up a picture of the size of your snorkel where it connects up to the OEM Z4 intake hole. I think I made a reference to that when I posted up the" how to" install the CSL intake on the Z4. Flow dynamics? Nfi, but just looking at the restrictions the OEM intake hole gives, doesn't look to me that it flows that nicely.
Please take a look at any of the race prepped z4m motor sport cars, and have a look at how they have the air intakes set.
They pretty much cover the WHOLE frontal area.
.jpg)