Opinion/Reviews Wanted! K&N Air Filter
 

Hello again my friends! Since I’ve been stuck at home I’ve just been trying to do as much maintenance and upgrades as possible on the 3.0. While I have considered getting a Cold Air / Ram intake, I am not currently able to fork the cash nor the time needed to set everything up. K&N makes a high flow air filter for the stock air box that I am looking at getting for the slight power improvement and the longevity of the filter itself, since they can be washed and reused. Although I’m a bit worried because my mechanic says to be weary of K&N filters because he has seen them destroy MAF’s day in and day out. I assume he’s talking about the oiled ones which means I just should get a dry one.

Any thoughts on this? Experiences of your own? Advice or warnings? Anything to help me make an educated purchase would be appreciated!


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Drop in replacement, Works as designed. More air flow with oil coated screen.

All the issues are from users "re-oiling" the filter, just buy a new one.

I have used them for 30 years and they work as intended. On BMWs I do not recommend them as there has been one too many posting of MASS Air Flow Sensors' heated wire getting contaminated causing codes. User over oiling? Who knows..

Brands: MANN C29105, WIX 49907, HENGST E409L
Source: www.Rockauto.com


Replace your CABIN air filter as well
MANN CUK5366 Carbon Filter; With Activated Charcoal

The issue with the K&N oiled filter is that they lose their efficiency really quickly...so you will have to wash and re-oil them often if you want their "free-er" flowing advantages. For a big lump as the X5 paired with the little M54, I would just skip it. Heck, I'm too lazy to even clean a dry aFE drop-in filter every year. I would just rather replace an OE filter ever 2 years rather than having mess with cleaning it.

I have been using K&N Filters (Drop-in Replacements) literally for decades, and YES, they flow better than paper, and YES, they can be cleaned and re-oiled. Check YouTuber "Engineering Explained" for his evaluation; search <Performance Air Filters>. Further, the cause of MAS wire contamination is residual combustion chamber gases condensing on the "cold" wire surface after engine shut-down, sneaking past the "closed" throttle plate. It happens with EVERY type of filter. Want proof? Switch back to your (removed) factory-paper after using the K&N for a while, and see. Good luck...

I’m not wanting to get into a argument over what is best.
This is a link to a very good, non-preferential testing. People can then make their own conclusions. YMMV
https://youtu.be/sJ3L-E-ufYo

Great video. Very informative. I wish he had tested a Mann filter.

So, just one brief question then. The last set of testing which was about the ability to filter contaminants, the K&N did significantly worse. Should that be concerning or does that have to do with the way it was oiled, etc? While I want more performance, I don't want all kinds of crap being sucked in. If you guys think the difference is negligible, then I'll probably just ignore it. \

Second, so no matter what kind of filter you use, the damage to the wires from getting gunked up is probably only worse if you over-oil the K&N, correct?

In my understanding of the video, the K&N had the best performance but the worst at keeping from contaminates from entering the engine. The test showed a out of the box filter with a lot of oil from the factory.

For me, since I am never racing my SUV, the K&N would be the last choice for my X5.

I'm trying to find one that
1) Sounds good (like engine noise coming out through the intake) which i think is more of the airbox than the filter but, its whatever.
2) Improve performance
3) (Ultimately) Save money with a re-useable filter
4) Not affect the longevity or maintenance of the engine in any negative way.

Anything that flows more will filter less.. (generally speaking).