Hey guys,
I just purchased a used aFe Intake for my 2006 325i Sedan. After installation the intake sounded amazing however the car did not run right. After assembling and disassembling the intake several times and creating my own gasket for the maf I was about to give up. I compared the stock intake and the aFe to find that the MAF sensor sits alot higher up in the intake tube on the factory box.
Issues: I experienced a huge loss in power between 4000-6000rpm, and very evident engine surging (power for 200 rpms , no power for 200 rpm, power, no power, etc.) throughout the power band at WOT.
Solution: I created a spacer for the MAF out of 1/2 inch MDF board. I also made a gasket out of 1/16 inch thick sheet of rubber to go between the spacer and intake tube. I did not need a gasket for the MAF to spacer since the sensor already has an o-ring, however the hole in the spacer must be perfect for the MAF to stay sealed. Longer bolts (extra 1/2 inch) had to be sourced.
Here is a diagram:
Outcome: The car now runs perfect, cannot feel the slightest stutter, power seems to be good and engine revs smoothly regardless of throttle input.
I am glad I decided to try this instead of giving up, as this is the best sounding intake I have heard for the E90/E92. I hope this can help solve some of the other members issues with this intake since research showed there is quite a bit of you with similar problems.