[Black Dog]

The question is about dual cone intake and any other intake that improves air flow. It's obvious that these filters offer higher performance figures, but it's also obvious that there's more dust particles that get inside engine and in the long run can cause major problems with turbos and engine itself.

I decided to raise that issue after 2 dealerships in my country mentioned that what is good for motorsports is not always good for daily driving.
I know that any owner of DCI(or any other filter that increases air flow) should clean it every 10k miles, but is it enough?
Has anybody had any issues with decreased air filtration?
Maybe somebody could shed some more light on the issue?

[tscdennab]

There are some ISO filtration standards that the filters must pass in order to be sold. Both K&N and S&B filters pass those standards. There is some detailed info on S&B web site.

[Black Dog]

Thanks for the info.
K&N and S&B(never heard about them) filters must be popular in Europe, but what about BMS and AFE? Although I hardly doubt that BMS and AFE filters have different production standarts.
Do these standarts prove me wrong with my filtration worries?
Does anybody know how different are filtration figures between DCI and stock airbox?

http://www.jlevistreetwerks.com/3-Se...duct_info.html

According to the link AFE Pro Dry S filter has 99.2% filtartion and AFE Pro 5 R (oiled) has 98.6% filtration, does the stock box have 99.9% filtration?

[Ilma]

BMS sells the S&B filters as part of their kit......they don't actually manufacture them...lol

[fluidkaos]

There is no more dust or grit getting past the filters with an aftermarket filter than with the stock filter. In fact depending on what you get, it is very likely cleaner air with an aftermarket filter. The performance increase is due to an increased filter surface area which has a lower restriction to airflow, thereby allowing more air through.

[BMW1986]

One of things that I found that helped reduce dust/dirt from the engine bay was to remove the cowling that connects to the stock airbox and replace it with this..

http://www.shop.stettperformance.com...3&categoryId=2

Also looks a lot cleaner (no pun intended), meaner, and open.

[cstmx_ryder]

^ ya, but for those of us that have DCI, the first part of the snorkel (the one that's being replaced on Stett's website) helps direct air towards the filter themselves. Yes, it looks unfinished, strange, but doesn't that still kind of serve a purpose?

[Jeff@TopGearSolutions]

Aftermarket scoops show more air flow into the engine bay. Stock opening is mediocre at best.

Closing it off would only be recommended for those with a true CAI.

[BMW1986]

I am running a DCI....

[Black Dog]

Can anybody say anything about filtration issue?
What do the guys at the dealer shops know that I don't or maybe what should I know that they don't?

[JunkStory]

There was a comprehensive test done showing that paper air filter (like the OEM ones) filter out more particles than the K&N and other aftermarket/reusable ones.

[Black Dog]

Thanks for that, I'll try to google it.