Hey guys! I just recently purchased me a project car (2003 BMW 330Ci) and I'm going about repairing any damage there might be to the vehicle from useless former owners who don't properly maintain vehicles. So far it needs a new front right shock and new brakes in the front. In the past, I have always stuck K&N Cold Air Intake kits (like the one in the picture provided) on them for the better airflow, supposedly better filtration, and the sexy ass noise they make when the throttle is depressed and the intakes open up.

But recently, I've been doing some reading on the internet and people have been saying that K&Ns don't filter as well as the stock and can damage the engine! Now, I've been running these filters for a while and I haven't had any huge issues like people have been reporting, but most of the cars I stick the CAI's on aren't in my possession for more than 4-5 months and I have no idea about the lasting consequences. I know for a fact that we have some gear heads in the audience and I was wondering if any of you have heard anything about this or have experience enough to comment.

Picture is of a 2002 E46 M3 with the intake installed.

They more than do the job man. I had a K&N cold air intake for my Jeep for 150,000 miles and never had an issue including some very serious offroading. My only concern was water but I don't see you going through any mud puddles anytime soon.

I've turned wrenches since I was old enough to pee straight, and what you've heard is correct, the K&N filters do FLOW very well, but their filtration is marginal to say the least, you actually get better filtration the dirtier it gets. I have a competition grade rockcrawler that my wife and I tow around the country and wheel, and I had a K&N conical filter similar to yours and the intake tube, the throttle body and the intake manifold plenum were always collecting dust ( and not just a little). All my connections were tight and were sealed, the only way the dirt was getting in was through the filter. I still can't believe the amount that was found in the tube of the cold air intake, I binned every K&n Filter I owned after that. I run sometimes in very windy, dusty deserts, so my dirt and sand ratio will be greater than yours but it's still no excuse. I run an Amsoil Nanofiber filter, re-usuable, but you just blow it clean versus oiling, it has flowed very well, and my dust issue is non-existent. Get me the dimensions of your old filter and I can order you one if you decide to go that route. The pricing on the website is MSRP, I get a discount since im a preferred member. Im not a salesman, I just had good luck with that filter.


AMSOIL - Synthetic Oil, Motor and Engine Oil, Lubricants, Air Filters, Oil Filters and Greases

I am a maintenance freak, everything I have gets serviced by my own hand regularly. I use to run K&N filters on quite a few of my vehicles, till I witnessed first hand this filtration issue.I'll dig out the pictures if I can find them, it was that much of a problem. Best of luck man.


Here's a video of my rig out in Moab, Utah (sorry about the one minute line prep, that bad boy was steep haha)

I've run k&n in my dodge 4.7L for 176,000 miles so far. I do wash and re-oil every 3rd oil change or so. Gained about 1.5 to 2 MPG and when i was driving 100 miles a day that added up nicely.

All the K&N does is restricted the air flow less by not having such a tight nit pattern. Witch lets smaller dust particles through. Really what it comes down to is changing your oil more. On our oval track car we don't even run a filter. Well its their but we cut lines in it:) We cheat ;p All in the name of winning!

HANO, do they sell the conical-style filters? I checked their site but was unable to find what I was looking for.

Also, anyone looked at these 'foam' filter kits? Some people say they filter much better and work just as well performance-wise, but others say foam sucks because it clogs up really quickly. The reason I care about this car versus the ones I've sold in the past is that a very good friend of mine is going to be receiving the ride and I don't want it to cost him down the road with engine damage and what not. I'd hate for him to get it, drive it a couple years, and then get fucked over in the end. He's had it really hard and I just want him to have a car he can be proud of for once. He's the oldest of several siblings and basically raised his brothers and sisters because his mom is useless and his dad is STILL in and out of jail. He's going to college this upcoming year and I want him to have the car he deserves. I've already started teaching him how to change the oil on it, maintain the brakes, etc.

For a guy whose website is aptly named Bob is the Oil Guy, its a pretty damn good test. I was actually quite impressed with the level detail. The statements made by K&N, Conforti, etc. leave out of their 'tests' and arguments.

Filtration Testing for Amsoil, K&N, Napa, Jackson Racing, Baldwin, and Mazda air filters on a Miata

HANO - That is fucking sweet dude! I'll forgive you for taking the extra look - danger.

Sweet Rig!

Agreed. Nice rig, HANO.

Thanks for the compliments. Good test on the filters Boon. I only have experience with the newest Amsoil Nanofiber filters, which are a dry-flow filter that does not require water to clean, or oil for filtering. It's essentially a paper filter, just using synthetic materials.....just blow and go. I believe Amsoil stopped using the oiled filters a few years ago, I just wish the new media was in that test, as I would be curious on his findings. Here's the the link for the Ea Nano filters.

AMSOIL Ea Synthetic Nanofiber Air Filter (EaA)

btw if you e-mail them they will give their test findings on a spreadsheet, I did that when I was researching Bypass oil-filtration systems for my cummins equipped tow-rig, to comapre their bypass filters with Wix, donaldson, fleetguard, and Napa Gold bypass capable filters.

I like the idea and the research behind the synthetic fibers, but the real question is do they make a cone that works with a CAI-style kit? I'm not looking for a drop in rectangular filter, I'm looking for a while kit. I can build the tube and what not from K&N or another company's parts, I just want the filter to be the right one for the application.

Oh yeah I use their cone style air-filter on my CAI (the intake tube was orignally part of the FIPK kit by K&N).



Here's the non-drop-in filters with dimensions.
http://www.amsoil.com/products/ea_fi..._and_Specs.pdf



Here's how they measure http://www.amsoil.com/products/ea_fi...U_Features.pdf


Again buy what your comfortable with, Im just throwing out there my personal experience!

And I posted here to get any experience anyone might have. Again, I want to make this car strong, yet reliable. I'd love to see what AMSOIL has to say about the dust that gets through and I might email them to get their results. I know for a fact that BMW lines the cylinders and chambers with a silicon-based sleeve that reduces the damage done by friction and particles, but the real mechanics behind it I don't truly know. All I've found is basically...

More air = More power
More air = More dust
Less air = Less dust
Less air = Less power

So, there's a tradeoff. You can't have both.

Originally Posted by Boondokk

...
More air = More power
More air = More dust
Less air = Less dust
Less air = Less power

So, there's a tradeoff. You can't have both.

Thats true for the most part, you have to give a little to get a little. You can however find a good compromise. best of luck