New Air Filter, what are my options?

[Jason]

I'm going to replace my air filter and I was wondering if anyone has any experience with the Green filters. Am I wasting my time with this or a K&N vs stock?

[mholbrook]

You should stay with the stock air filter.

The air box can take a little modification however. There is a horn in the bottom that silences the air in the box. It can be removed and I believe about a 4" inside diameter tube will fit on the short plastic flange that remains to direct air from behind the headlight (as in stock but about 2x bigger). You might feel a little more umph in the seat of the pants dyno and it makes for a little bit of throttle noise kind of like a 4-barrel carb kicking in. I'm using a left over Dinan tube on mine but you can make one that is just as good or better with a couple bux worth of Home Depot tubing.

[Jason]

I think im gonna stay away. I'm liking the idea of removing the horn though for a better sound at the very least. Also, can stock filters be cleaned like a K&N or do they have to be replaced?

[Bill R.]

a few years back where Jim Conforti JC chips did some dyno tests and tested it with the air horn in place and without it, and they lost something like 3hp with the airhorn removed... so bmw went to all the time and trouble to design that airhorn for good reason...

I think im gonna stay away. I'm liking the idea of removing the horn though for a better sound at the very least. Also, can stock filters be cleaned like a K&N or do they have to be replaced?

[Unregistered]

I put a Green replacement air filter in my 535ia in November after I purchased it. I talked to Will Turner a few years ago at a short lived American Le Mans Series DC race and he swears by them. I have been using a K&N oil filter in my 2002 since 1982. The motor was replaced in 1985 and it now has over 200k miles on it. I'll take that wear and tear anytime. I also have a K&N cone filter in my 1981 528i and a K&N replacement filter in my 1998 4Runner since it was bought new in 1997.
I just returned from a 1400 mile trip in the the 535i and averaged 23.5 mpg at 80 mph. Everthing else is stock except some 8mm sparkplug wires from BAV Auto. I think the key is to check, clean and reoil these filters on a regular interval. Just because they claim to be million mile filters the need to be maintained. If I'm creating premature wear so be it, I'm having fun at it. Just my 02 cents worth. Not trying to create any controversy.
Will Ollison alias "willobmw"
1990 535i
1981 528i
1975 2002

[Jr ///M5]

Jason,

The great board member Bill R. has done some research on this very subject. Comparing stock filters to others along with the K&N.

The findings were the stock filter had about 30-40% more particle catching material because of the pleats and their size. It wasn't that much more restrictive either, if I remember correctly.

So by sticking with the stock filter, you are protecting your engine the way BMW wanted you to.

You'll soon find that it's hard to improve on BMW's breathability from the air filter down through the head to the end of the tailpipe. The engineers really did an excellent job which is hard to improve upon.

Jr

[David Chen]

The only filter that works as well as the stock one at keeping out dust & grit while allowing better airflow is the ITG filter, available from www.sharkinfested.com, among others.

Cheers,

David

[Speeder 553]

The only filter that works as well as the stock one at keeping out dust & grit while allowing better airflow is the ITG filter, available from www.sharkinfested.com, among others.

Cheers,

David

It looks like the ITG Filters are better than most. Anyone using one? How does it work? Are they worth $68?

[Speeder 553]

It looks like the ITG Filters are better than most. Anyone using one? How does it work? Are they worth $68?

Or I could by four Mann stock air filters for the same $$ and replace them more often for better air filtration.

[ThoreauHD]

The stock Mann filters seem to do a great job for me. My car is whisper quiet and rev's consistently... for a V8.