K&N Filters and MAFs

I have k&n filters in my 355 and M5. the key is to set the filters out in the sun for an hour or two before installation to let the excess oil evaporate. I have had zero problems in my 355 or M5.

 

Did you see/feel a difference using the K&Ns in your 355? Any other issues or benefits?

Thanks much

 

20k mi with no issues. Better sounds, maybe a few horsepower.

 

Cool - good to know - Thanks. I have been considering it - good to know on the tip to let the oils dry though. Thanks all

 

I have used K&N filters on my carb 308 and later on a 328GTS. Also on various other makes and models. Other than a bit more intake noise, there seemed to be little performance benefit. I just use stock filters now.

 

Or in this heat, 5 or 10 minutes

 

Also used them in my 348 and currently in my 355 had no problems so far

I actually got the filters at a lower cost than a pair of standard Ferrari air filters so that helped with the decision .

 

It does take some effort to properly clean and oil them but they do work better than a paper filter. The oil on the cloth does a much better job of attracting dirt than a sheet of paper.

 

I have had them in my 1999 F355 for at least 4 years. No issues. After oiling lay them down on some newspaper and use a hair dryer. Doing each side. Let sit for at least an hour. Good to go.

 

After oiling i left the filters on some kitchen cloth, on the house radiator for à night..
Works great in the cold area's.

Regards Ben

 

No issues here. Been running a K&N filter on my 348 for the past year and a half.

 

not to push my blog, but this is my take on the whole deal . . .

http://sandiegobmw.wordpress.com/2008/06/23/bmw-air-filters-things-to-know-about-performance-filters/

 

I just don't like the oil situation. Oil belongs in the sump, not the intake.

 

Not universal by any means. BMWs after about 1995 have low quality MAFs made by siemens (most of the time). they are extremely prone to failure and rather delicate. I have changed more MAFs on cars fitted with oil saturation filters by almost ten fold. They are so bad that if you try to clean them with MAF cleaner you can pretty much kiss it goodbye. Again, not all the time. The early MAFs, such as the one on my '95 F355, are much heartier and you can clean them, etc. BMW stopped using those in about '93.

Largely my problem with these filters is that they really are nothing more than a product of great marketing and have nothing much to do with technology. The reason the ping pong ball floats higher is because that filter is filtering less. These filters, like F1 transmissions, and SMG on BMWs, are yet another example of "it's on the race cars!" marketing. What people fail to realize is that race teams do this stuff to gain that little extra and most of those engines will only see a short period of time in use before a complete tear-down. The average consumer does not have that luxury.

Basically, the harm these filters cause are not outweighed by their benefits. Stick to stock.

 

I tried K&N filters on my F355 for the possible HP gains. Then after seeing the same air boxes/filters on the 12 cylinder 550 .... I figured the paper filters should suffice on our smaller 8 cylinder engines. Also during some dyno tests for other reasons ...... I swapped the between paper and K&N filters, with absolutely no effect on HP. I am sure there are benefits to K&Ns on other cars or intake configurations ...... just not on a stock 355 .....

 

I think the fact that they're cheaper is a benefit

 

I ran my K&Ns strictly for increased filtration in the extremely dry, sandy Texas climate.
I had two sets and would alternate between changes. After oiling the replacement set, I would let them sit overnight on several layers of that heavy brown absorbent paper. I would also always remove the MAF sensor and use an entire can of CRC MAF sensor cleaner - spraying from both directions (be very careful with the MAF internal sensor area, do NOT blast it with compressed air to speed drying).

However, Brian Crall then posted that the OEM paper filters were actually more efficient at filtering fine particulate matter and clogged less than the K&Ns. So, I think I'm going to go back to paper OEM filters at my next change. BTW, I still plan to clean my MAF at every filter change, even if I'm not using K&N filters (cheap insurance).

 

Good post. My previous logic was that the oil film on the K&N filter gauze would be more efficient at attracting particulate matter (e.g., sand, dust, etc.) in the dry Texas environment than the OEM paper. However, after doing some research and remembering Brian Crall's post (see above), I think it actually is LESS efficient.

I also agree on the potential of oil contamination of the MAF sensor. It doesn't take much to screw one of those up and the 94/95 F355s have two ($$$$).

 

What is everyone here using to clean their KN filters?