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Discussion Starter · #1 ·
Hey all..i'm a new E39 M5 owner and that's my real first post after getting me The Beast..i have found that this forum has a lot of info and really went through a lot here on the forum before i finally decided to buy an M5 so clearly one of the reasons i bought this car is this forum and the members and i'm happy to be a member too..so thank you guys..all of you.

I bought the car 2 days back..and it was parked for almost 5 years as the previous owner immigrated to Canada and he left The Beast parked in his garage doing nothing..took it for a full service..changed mostly every thing..oils..fuel filter..plugs..etc..and the car started breathing again..took it for a run..wasn't that fast or strong..but considering how it was before the service..i'm happy for what i have for the moment.

So here comes the part i'm shocked from..i decided to put 2 AFE sports filter "Big Ones" i left the lower part of the stock air box and i just pulled out the stock filter and installed the AFE ones..since in all the Bimmers i owned..a sport air filter made the car more smooth and sounded awesome..but with this car..i felt lag of power..a real big power lose..the car hardly goes to 6000RPM and i feel like it has a 3.5 V8 engine !! Did any one around here experienced that issue before..did i do the right thing or what i did was a big fail from my side..i feel the engine is more smooth..but i don't need that..i need power..should i put back the stock air filters..or can i use the K&N "The Squared ones that fits inside the stock air box"..guys what should i do..am i imagining all that..or its true ??????..Thank you all for your help in advance :biggrin:
 

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I don't recall this type of conditions immediately after someone replaced their air filters. I suggest you replace them with stock ones, and keep them there. No benefit to replacing them with any other kinds. Stick with OEM.

IF the issues still occur with the OEM filters, then it might be something else.
 

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Check everything over from your install. MAF unplugged? Bad connection or cracks in the intake tubing causing a leak after the MAF? Five years is a long time to leave rubber unused. When the car was in for service, were any vacuum lines replaced? It's probably something easy that was overlooked.

good luck

dj
 

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Discussion Starter · #4 ·
djazz..nothing..i've checked all the tubes..nothing is wrong with them..i felt that after installing the air filters !
 

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You've probably thought of these too, but I'll still ask to be sure it's covered:

Did the lines running under the plemun get checked since you bought the car?

Have you checked for any codes?

Are the AFE filters oiled? (I don't use them so I'm not sure.) Excess oil could foul up your MAFs (And some say any oil on the filter is too much.), but I believe it would take a while to cause a problem.

I'm trying to hit the "big picture" problems also, since you indicate it was low on power from the beginning. I imagine your problem is one of two things. Either an existing problem has crossed a threshold due to use or made worse somehow with the filter change, or the filter change itself caused the problem.

dj
 

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Get a set of new original filters and see what happens....

There is no drop in filters for the stock air filter boxes that have better air flow than the paper filters.

But still the car should not be noticeable down on power with the aftermarket filters....
 

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Discussion Starter · #7 ·
Vantaam..r u sure? cuz i heard that the E60 has the same issue when you change the OEM filters..i guess i'll try again with the stock filters and see..cuz honestly...my car won't take a 320i !!
 

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What about the MAF's themselves? If its always been down on power maybe they need to be replaced/cleaned?
 

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Vantaam..r u sure? cuz i heard that the E60 has the same issue when you change the OEM filters..i guess i'll try again with the stock filters and see..cuz honestly...my car won't take a 320i !!

e60 m5 uses a different type of MAFS, if i'm not mistaken. The MAFS on the E60 requires a laminar airflow over the sensor element - changing to a cold-air intake or other intake can eliminate BMW's efforts to maintain laminar airflow over said element.


I would venture a guess that your MAFS are to blame, NOT the filters.
 
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