[1GrayBulldog]

I had a moment to check back into the forums after being away a while, and thought I'd pass along a (hopefully) helpful tip for those who are running the AFE sealed/cold air intake for the F30 328i. FYI my ride is a 2013 (8/12-build) F30 328i with the electronic solenoid. Tranny is the sport-option 8AT. My AFE CAI has the oiled filter and I also run the AFE vent scoops. Other go-fast mods installed before the AFE are the BMS Stage 1 tune (+3psi setting but running on 93 octane), which was followed by the full Magnaflow cat-back exhaust system.

First off, unfortunately my ride was in a heavy aquaplaning accident 2 weeks ago so I won't be able to send pics of this until I get my car back late next month. However, for those of you running the AFE who check into this, what I'm referring to should be fairly self-explanatory without visual aids...

After installing the BMS Stage 1 and the Magnaflow (highly recommend both btw) I wasn't sold on spending the money for the AFE CAI because of the long-standing debate on how much bang for your buck an intake provides us with newer-generation bimmers. However, I was able to snatch up a used AFE from a fellow community member for a pretty good price. After installing the intake, there's no doubt the butt dyno registered an increase in performance; The performance impact from the intake wasn't as noticeable as when I installed the tune or the cat-back, but it was noticeable nonetheless. The intake seems to benefit top-end the most, especially in highway driving conditions. I used to sense the N20 showed it was a 2.0 4cyl past 4.5k rpm or so; almost as if the engine ran out of breath after passing through the bulk of the torque curve. With the intake installed there's less drop-off after the torque-pull we all know and love.

Since my AFE was used I decided to give the filter a nice re-charge cleaning and oiling a couple weeks after it first went on the car. After re-installing the filter I did a quick double-check of all the intake connections and fasteners, and that's when I noticed how poor the "connection" is between the intake itself and the tube/channel that runs to the intake from the air intake duct behind the front grill. The problem is that even when I re-positioned everything to perfectly line up the intake inlet to the duct outlet, there was nothing to seat the two together so a gap would always develop. In the end I used a decent amount of duck tape all around the connection point to seal the intake to the duct. Once you get into the engine and examine for yourself you'll see what I'm referring to.

With the intake sealed up like this I felt the positive effects of the intake were definitely increased from before sealing the connection, again with the greatest difference being felt on top-end power. Sealing the connection made the intake even sound different than before (mostly the timing and volume of the off-throttle hisses), and I calculated out an average 1.9 mpg increase over the fuel-economy test I run in highway cruise on my commute (5x round trips).

I'm interested to see if someone else tries this relatively simple mod to their AFE and finds the same positive effects result...