BMW M5 Forum and M6 Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
4,246 Posts
Robert:

This is a common topic on here. Many members have found that the K&N cause MAFS fault codes and have since removed them while others have ahd no issues. I would say skip them and do not deal with the hassles they cause for the minimum if any power increase you will get. Hope this helps.
 

·
Registered
Joined
·
5,353 Posts
Don't. Over time, the oil from the gauze will contaminate the MAFS. It's really insidious, because sometimes the power only goes away gradually and won't throw off fault codes until they're really bad. The M5 has so much power that if it goes down gradually you can fail to notice quite a bit of HP until it's suddenly restored with new or cleaned up MAFS.
 

·
Banned
Joined
·
300 Posts
So even warned, I still installed K&N filters.....just recently with 2k miles of driving I developed hesitation after driving the car on a cold engine.......so I decided to clean the MAF sensors with "Formula 409" using previously posted instructions........and now the car feels new again with a smooth acceleration on all gears....
http://www.walgreens.com/store/product.jhtml?CATID=100468&id=prod372197
 

·
Banned
Joined
·
300 Posts

·
Registered
Joined
·
310 Posts
Here goes my opinion on K&N:
They do allow more air through the filter when new, becuase they dont filter as good as paper! Its real simple, they filter less that your OEM filter, allowing particles to enter your cylinders.
Then when they get dirty, they allow LESS air to pass than a paper filter with the same mileage.

Any K&N users, look at the inside of your intake tubes when you take a dirty K&N off. Look at all the silt stuck to the side of your intake tubes, thats the stuff getting by the filter.
 

·
Registered
Joined
·
837 Posts
I thought I was going crazy, I didnt realize there was 2 concurrent Threads titled the same, AAhhhh!, Josh
 

·
Registered
Joined
·
3,176 Posts
PilotMike said:
Here goes my opinion on K&N:
They do allow more air through the filter when new, becuase they dont filter as good as paper! Its real simple, they filter less that your OEM filter, allowing particles to enter your cylinders.
Then when they get dirty, they allow LESS air to pass than a paper filter with the same mileage.

Any K&N users, look at the inside of your intake tubes when you take a dirty K&N off. Look at all the silt stuck to the side of your intake tubes, thats the stuff getting by the filter.
After 15K miles with the K&N filters, I decided it was time to clean them. First thing I looked for was any signs of "oil contamination" on the ducting after the filter towards the MAFS. Wiped with a cotton cloth and no signs of oil residue. Cleaned the filters per K&N instructions and reinstalled. So far so good.
 

·
Registered
Joined
·
400 Posts
I had K&N's in my car and the MAF"s got fouled. BMW tech tries to clean them and that did not help. Had to get new MAF's . Needless to say, the BMW filters are in the car now and I noticed no difference in performance.

It would be interesting to note if the dual air intake system of the M5 and its factory paper filters is so marginal that it cannot supply adequate air to the engine as needed. I find that rather difficult to believe. I would think pressure drop numbers across the filters would answer that. If its just a few of inches of water, then who really cares.
 

·
Registered
Joined
·
321 Posts
Re: Jetex / K&N Filters

put jetex oil filters in :M5thumbs:

mafs fouled in 1000 miles :sad1:

mafs replaced :M5thumbs:

tried agiain same result :sad1:

back to stock a/ok :M5thumbs:

replacing stock filters of no benefit :grrrrr:

worthless mod :byee55amg

welsh willo
 

·
Registered
Joined
·
1,553 Posts
Here's what K&N have to say about this issue...take it for what it's worth and thanks to Daniel (Beastpower) for this statment:

"At this time, K&N is unaware of any evidence that K&N air filter oil from a K&N air filter can damage or cause the malfunction of a MAF sensor, regardless of the make of the vehicle involved. K&N takes seriously any claim that one of its products is incompatible with its designated application or can damage or cause the malfunction of any automotive component. Such claims are thoroughly investigated and, when appropriate, testing is undertaken to determine their merit. In the case of MAF sensors, ongoing tests have shown that contamination from K&N air filter oil has not caused any failures or malfunctions of the MAF sensors in the test vehicles. K&N is aware that MAF sensors can become contaminated for a variety of reasons, unrelated to a K&N air filter (such as backfiring, blowby, leaking airbox or leaking intake duct) and that various methods have been used by some service departments and repair shops to clean a dirty or contaminated MAF sensor, such as spraying with an appropriate cleaner. K&N has not completed any tests as to the efficacy of such a process and, therefore, does not officially endorse or recommend any cleaning process. However, if given the choice of either replacing a MAF sensor or cleaning it, K&N recommends that the consumer ask his or her automotive dealer to attempt cleaning, before replacement. It should be noted that the presence of contamination does not mean the contamination was the cause of the MAF sensor failure. Sensors can fail for electrical or mechanical reasons, unrelated to any visible contamination."

:cheers:
 
1 - 14 of 14 Posts
Top