Hi guys,
Has anyone swapped out the car's stock air filter and replaced it with a free flow air filter, K & N or similar type of filter.
If yes, was it worth doing? My opinion is, it's not worth putting an oiled filter as it might mess up the MAF. Am I wrong?
Last, is there a dry non oiled high performance air filter on the market, better than the OEM filter.
Thanks

 

There are a couple of threads on here about this. Mixed views.

My view for what it's worth it that the Oil may well mess up sensors and it is very unlikely to make any measurable difference. Others disagree.

 

+1. And the power increase of "free-flow" filter media has been debunked. The design of the intake tubing and flow through the filter housing (maintaining laminar flow) has a far greater impact on power production.

 

K&N is snake oil at best, plus you have to maintain them.

 

Back when I had my supercharged DINAN S3 M5, the air filter was a dry version of the K & N sir filter, plus a DINAN sock over the filter.
Is there a dry version high performance filter for our cars.

 

I'm with the others......no K&N's for me. I've had in depth discussions on this topic on several motorcycle forums as well as the turbodiesel registry and the short version is I won't use them, and I'd especially avoid them on engines used in dirty environments or forced induction engines.

Dave

 

Friends don't let friends buy K+N filters....

 

The theory on the dry vs oiled is that the oil traps more dust particles. The oil isn't really an extremely wet type so no it won't go through the intake system and clog up the MAF. They do need to be "recharged", but not that often. And no they won't provide any real additional power; it just comes down to the filtration performance.

 

Filtration tests have shown the ineffectiveness of the K&N filters:

https://www.bobistheoilguy.com/airfilter/airtest1.htm
https://www.bobistheoilguy.com/airfilter/airtest3.htm

 

I'm aware of the theory, I've used oiled foam filters on my racing bikes for decades....but as far as K&N's go, they don't filter well and the oil often gets everywhere, particularly on boosted engines. MAP sensor contamination using oiled gauze filters is very common.

Dave

 

Thanks for the replies guys.

 

I can pull up filtration tests that show the opposite. There are many across the web and this has been debated for over 15 years.

 

I hear you, but even K&N admits their filters screen only 99% of what the OEM filters can do.

 

Over 45 years actually, as these filters first appeared in 1969. There's no more substantiation today for any of their claims than there was back then.

 

I've tried them and have seen the evidence visually and with oil analysis results......run whatever you like in your car but I won't use them.

Dave

 

Yes, there is always a trade off (i.e. more air, more power... more air, less filtration). I'm not suggesting to run them, but I am saying they do not clog MAF's.

I haven't followed K&N specifically, but I spent a lot of time in the import modification realm during the 90's when that was "the thing". I've seen all the tests for an against (whether it's filtration or dyno) for various intake manufacturers over the years (using various filter types). However, I've yet to see an engine failure directly related to any specific filter type.