I have heard bad things about the aftermarket filters. Do a search and you should find some information about it. I seem to remember an instance where the filter actually decreased performance. You can never go wrong with OEM.:thumbup:

 

I installed a K&N filter. I did not notice any change when driving. I may have gained a HP at the most.

 

if you just want some extra sound, remove the intake resonator, sounds like half a CAI

 

i have a partially used replacement k&n filter someone can have
doesnt have that many miles on it as it got replaced by my gruppem...i'd sell it for $30 shipped.

 

The problem with aftermarket air filters is that they aren't as good at keeping rogue dirt particles out of your engine. Some say that this is negligible and worth it. While others can't imagine why you would subject your engine to such a thing. Either way you probably won't notice much of a change in performance.

 

do a search, samir did a dyno with a stock 330 with an itg drop in filter. something like a 3hp gain.

 

I bought a K+N air filter a month or so ago and I did notice I got a few miles per hour out of each gear. I love 3rd on the highway and I can get to 98 or 99 MPH where I only got 95 or so before. It was 40 bucks, not to bad.

 

If the BMW has a MAF like my IS300, I would watch out on the K&N style ones. The oil from my TRD filter built up on the MAF meter and threw off the readings, the car started running terrible and eventually would not start. A little bit of research and I found that was the problem, it was as easy as cleaning it with electrical parts cleaner, but I was worried it was a much bigger problem.

Ohh yeah, and I live at a high altitude, and still notice a small gain with the aftermarket filter

 

I have K&N filter and I believe it helps breath better at high RPM. Won't notice a gain but a little gain. I think it will work better with a chip or software upgrade.

 

supposedly, over in germany people don't put intakes as much as in the states due to the belief that its bad for your car at the end of the day.

 

do a search, samir did a dyno with a stock 330 with an itg drop in filter. something like a 3hp gain.

Wow....3hp gain? not bad for just a drop in mod, right? But i wonder if it was really that much of an increase. Most people report only a negligible improvement in hp...maybe 1 or 2hp. You guys think it's worth the risk of damaging my engine or is it pretty safe to use?

To all you guys that have the drop in filters, do you guys notice any dirt or debris around the MAF?:dunno:

 

I bought a K+N air filter a month or so ago and I did notice I got a few miles per hour out of each gear. I love 3rd on the highway and I can get to 98 or 99 MPH where I only got 95 or so before. It was 40 bucks, not to bad.

Changing out your filter will not...in ANY way change your gearing! It might increase your HP meaning you will get to 95mph quicker...but in no way will it change what gear you will be in at 98mph or whatever. You may have just been shifting at a higher RPM...

 

Ah, the almighty dyno.

Beware! That 3 HP air filter gain might be *awfully* close to the margin of error. In other words, if they did another pull with the stock filter, they might've gotten the same reading.

Just be careful of any claims in the low single digits... the dyno, nor it's operatior, ain't foolproof.