Why is it that people suggest to go with BMC instead of K&N for the air filter? K&N is half the price, what is so better about the BMC?

thanks.

 

I say OEM paper. No blown MAF's

 

i know that is a old thread but i was wondering if the K&N filter is good and if anybody is using it, thank you !

 

Where is OAK...mad power!

 

Been using a K&N since the car was purchased 18 months ago... My Avatar says it all...

With "ANY" of these "maintain them yourself" filters, you risk over-oiling and blowing a MAF. You've been warned!
Mike

 

I use BMC filter but it has been cleaned prior to use so less oil on it. No problems at all... 6 months in use

 

I just bought a new BMC filter and flushed it freely with the garden hose, let it dry and then installed it. There was a bunch of oil in the runoff so way less chance for contaminating the MAF.

 

I plan to stick with paper for a bit and perhaps go with the "dry" unit at GMG.....perhaps.

For now, my thoughts are this. Say you have 540 or so hp....and the filter gives you 10 more. Can you feel that? Does it matter....and a MAF is 140 bucks now from John D. So, not as bad as it was, but it is still not free.....is that worth the risk...? In theory, the OEM filter gets more junk out of the air to protect the engine.

So, we have huge threads about what oil is best for the engine, and then allow filters into the car we "know" let more dirt into the engine....there is a disconnect here that seems silly to me. Data exist showing all the aftermarket filters let more dirt into the engine. To my naive brain, dirt means wear....oil contamination, etc. So, I have voted to NOT go for 10 more HP now and will just deal. My plan is to change the OEM filter a lot. I found a bunch for 19$ each, so I have about 9 of them left....that should last a while.. :-) I like the look of the dual head units out there, but I am not convinced that at 540HP I'll see anything from them. Tom Kerr, with a bigger engine, has data yet to come to the table that will tell me a lot. Until I see road data, I am sticking. I like the fact that with the OEM unit rain/washing is no issue. I drive in all four season with abandon. Highly recommended!


Now, if I had an 700+ hp car and hp was my main concern for whatever reason, I "might" do the fancy filter...but for my meager skill set, 540 hp seems more than what I can use on a track, let alone the road. I did a four wheel drift at 90 mph on track in the car (on purpose sort of....)....on street tires so tires are likely the next step, but HP is not the issue....that was in 3rd gear....


Back when I had a 3.8L 993 C4 with ti springs.....my Memphis tuner/shop told me about a test they did with an OEM filter on a dyno. They took the unit, covered half up with duct tape ....no change. Then another half up...no change, then another. Only when under 1/16 of the surface was there on a new filter did numbers change. That to me was staggering data (memphismotorwerks if you want to check out my source). Their take home message was that if you change the stock units every 10k, nothing will likely matter (and they were big into not letting the engine walls get scraped up by sand/dirt....which I fully support as I don't have that kind of cash).....just data. They also did test of "washed" K&N's before and after and the after units were never as good as new units "de-oiled"...their theory was that it was hard to get dirt out of the filters....I buy that. Hence, I am a big fan of tossing the oem out.

If I did aftermarket, I'd probably toss them ever 15k to 20k and not even try to wash them....if I was about the HP, I'd just consider them an expensive disposable and not even try to wash them. My way of thinking. ...you have a 50-100k car, and if you need that filter probably closer to 100k....who cares about that 100 dollars tossed.....

If I had a high HP car, I am convinced the way to go is BMC with the oil all but washed off via dish soap....per a lot of internet searches. I'd buy a new one, do that, let it dry out completely and then install it. 15k miles later, I'd put a new one in....my way of thinking if I wanted to optimize my HP. Save that, paper is the way to go in my mind. And, I'd change oil every 2-3k miles as it would be a lot dirtier with the BMC or K&N...and that would be one expensive engine problem.....if not kept clean.




JB

 

I'll add this additionally... Much like "other" parts on my car. If I were buying and installing them, I would have stuck with the paper filter. Mine came with the car, so I'm using the K&N.

Mike

 

frankly they so identical you will struggle to tell the difference, so go K&N

 

I Installed BMC from last year from the box to my car no rinse with water e.t.c No MAF problems at all.

 

I have a BMC in a fabspeed airbox. It's open to the elements. The sound is great, but it sure collects the dirt. Here in Oklahoma the wind is almost always blowing so it's a high maintenance item.

 

Some fun reading....

http://www.exploroz.com/Forum/Topic/..._KN_types.aspx

http://mymiata.paladinmicro.com/K&NComments.htm


Just some thoughts. Do any of you guys actually "feel" the extra 10 hp? I don't come up with this stuff. My favorite argument is this...if the filters were so much better, why wouldn't Porsche use them OEM?

I used to feel K&N's were super cool...food for thought. This stuff is constantly debated. I love the looks of the double snorkel intakes and I am sure sound is neat, but one thing comes to mind:

when I listen for a carotid bruit (sound), I hear sound if things are non-laminar (blocked). If the air flow is absent it means either the flow is superior (smooth) or completely gone. Since my car is running and I don't hear the intake, this logic makes me feel the air flow in is not the issue. IF I heard it, I might like it better, but that would suggest turbulence. Simple fluid dynamics issues (yes, I have a physics PHD).

Jeff

 

I also feel most "performance" air filters trade off filtration for extremely marginal (or no) improvement in engine output.

I feel people just WANT to buy SOMETHING that makes them feel good when they look under the hood. Heck, people will exchange a factory airbox that is designed to suck cooler air from outside the engine compartment for a cone system that sits in the hot air under the hood...these systems loose power compared to stock. But I am getting OT...

Here is a very interesting test:
http://duramax-diesel.com/spicer/index.htm

While K&N claims that are 'within 1%', when you compare say 99.9% to 98.9%, that "1%" can be TEN TIMES more particulates getting past!

For engines that are raced, and rebuilt regularly, who cares? Give me paper filters and I'll just replace them with every other oil change.

 

Wow, that data supports the fact that the foam AND K&N get full of dirt fast and pass dirt fast (about 20x as much in less time...).

Had no idea it was that bad. That is sort of scary. Thanks for the link. I am sticking with paper for now. No GMG or other units any time soon. That is a huge dirt difference......for not enough HP/tq to matter frankly.

JB