It's time to replace the air filter on my MR2.
The previous owner replaced the OEM air filter with a K&N knock-off that's in pretty bad shape - clogged, rusting, etc. I would go for the K&N but I've also heard that the increased air flow = increased engine wear (it lets in more dust and dirt particles). Truth or fiction?
EDIT: Another issue I've heard is that the oil impregnated in the K&N can come off and damage the MAF.
I have K&N filters in my bike and Z28. I don't know if they make more power or cause more engine wear,but all the power junkies I know swear by them. I like the fact that I can wash and reuse them (they have a million mile warranty) as long as I own the vehicle.
I've never had any oil problems with mine.
I think most things said about K & N's is a myth, except that they'll last forever if you take care of them. I bet they would give enough power to notice if the old air filter was reeeaaallllyyy clogged, or if you replaced the stock filter with a bigger K & N. I actually have foam filters on the MG.
Improperly maintaining the K&N will damage an MAF.
The other thing to keep in mind is why they use oil as part of the filtration system. Think about it.
at worst (well given correct usage) the maf becomes dirty and can be cleaned in 5 seconds with some electrical cleaning spray. The use oil because it allows them to get similar filtration with less resistance....
Quote from: gotta-qik-z28 on May 04, 2009, 10:28:46 PM
I've never had any oil problems with mine.
You don't have any sensors to contaminate.
Quote from: Speed_Racer on May 04, 2009, 10:10:57 PM
It's time to replace the air filter on my MR2.
The previous owner replaced the OEM air filter with a K&N knock-off that's in pretty bad shape - clogged, rusting, etc. I would go for the K&N but I've also heard that the increased air flow = increased engine wear (it lets in more dust and dirt particles). Truth or fiction?
EDIT: Another issue I've heard is that the oil impregnated in the K&N can come off and damage the MAF.
I would put a paper filter in there. I use paper filters in everything, including the WRX. Not enough of a difference can be felt in the butt dyno to use them, IMHO. The paper filters keep out more dirt, flow more or less the same, and you don't have to worry about it effecting sensors. That said, I still recommend periodically cleaning off the MAF with a plastic-friendly cleaner like CRC's MAF Cleaner.
Quote from: Speed_Racer on May 04, 2009, 10:10:57 PM
It's time to replace the air filter on my MR2.
The previous owner replaced the OEM air filter with a K&N knock-off that's in pretty bad shape - clogged, rusting, etc. I would go for the K&N but I've also heard that the increased air flow = increased engine wear (it lets in more dust and dirt particles). Truth or fiction?
EDIT: Another issue I've heard is that the oil impregnated in the K&N can come off and damage the MAF.
K&N filters are a waste of money, pure and simple. The let in more dirt don't add much if anything to HP, and if they do it's generally near the redline (how often do you drive at that RPM).
http://www.nicoclub.com/articles.php?id=180100
See: http://www.bobistheoilguy.com/airfilter/airtest1.htm
http://www.metrompg.com/posts/air-filter-part-1.htm No, or virtually no mpg gains.
http://www.autoblog.com/2005/09/07/how-well-do-k-n-air-filters-work/ Might save you a few bucks after a quarter of a million miles but how much is an engine rebuild?
K&N filters have only one benefit: intake roar. They do not add power or increase MPG, despite their claims.
No automaker is going to spend $25MM+ developing an engine only to hamstring it with an overly restrictive air filter.
And as we have seen, and true to aftermarket part performance, they are neither as reliable nor as robust as the factory stuff.
Quote from: GoCougs on May 05, 2009, 08:46:58 AM
K&N filters have only one benefit: intake roar. They do not add power or increase MPG, despite their claims.
No automaker is going to spend $25MM+ developing an engine only to hamstring it with an overly restrictive air filter.
And as we have seen, and true to aftermarket part performance, they are neither as reliable nor as robust as the factory stuff.
Unfortunately for you, Ayn Rand doesn't know jack shit about cars. Try reading some automotive literature, perhaps.
Quote from: NACar on May 05, 2009, 08:53:50 AM
Unfortunately for you, Ayn Rand doesn't know jack shit about cars. Try reading some automotive literature, perhaps.
What was the point of this post? He's absolutely right, you know.
Quote from: R-inge on May 05, 2009, 08:58:49 AM
What was the point of this post? He's absolutely right, you know.
He is not right right at all, and is obviously talking straight out of his ass, as usual. Are you trying to tell me that every single test that shows improved performance with a K&N filter was a phony? I've seen so many of tests from so many different sources, that I do not think it is possible for K&N to be paying off all of them. Actually, all of those links that Byteme just posted (except for the first one) prove that a K&N is less restrictive and improves performance over paper filters.
Quote from: R-inge on May 05, 2009, 08:58:49 AM
What was the point of this post? He's absolutely right, you know.
Yeah, I'm not sure if he was joking, or serious, trying to make a funny, or just trundling in out of boredom...
What I have read about the subject is that automakers spend quite a bit of money on intake filter/box/tract design, to take advantage of the pulsing effect of the intake charge WRT to the firing of the cylinders. This advantage is along the lines of throttle response, and otherwise maximizing performance.
The specifics are well beyond my knowledge, but it's enough for me to say I think that yeah, a team of dozens, scores, maybe hundreds of power train engineers, who are are spending tens or hundreds of millions of $$$ developing an engine, aren't going to botch the whole process with an overly restrictive air cleaner.
K&N are for intake noise, and one risks contamination and other hassles.
Quote from: GoCougs on May 05, 2009, 09:09:00 AM
Yeah, I'm not sure if he was joking, or serious, or trying to make a funny...
What I have read about the subject is that automakers spend quite a bit of money on intake filter/box/tract design, to take advantage of the pulsing effect of the intake charge WRT to the firing of the cylinders. This advantage is along the lines of throttle response, and otherwise maximizing performance.
The specifics are well beyond my knowledge, but it's enough for me to say I think that yeah, a team of dozens, scores, maybe hundreds of power train engineers, who are are spending tens or hundreds of millions of $$$ developing an engine, aren't going to botch the whole process with an overly restrictive air cleaner.
K&N are for intake noise, and one risks contamination and other hassles.
You are denying the results of thousands of tests because of a subject that you admit is "well beyond my knowledge".
Your "pulsing" effect of intake flow takes place most importantly in the intake ports and the manifold, and is almost irrelevant by the time it gets upstream of the throttle body. We're talking about air filters, not intake design. Any restriction in the intake path that is not designed to increase velocity or induce swirl is going to decrease the volumetric efficiency of the engine. K&N's flow better than paper. Period.
Wow, this is an exact cross-section of what I've read on other parts of the internet.
Quote from: NACar on May 05, 2009, 09:05:09 AM
He is not right right at all, and is obviously talking straight out of his ass, as usual. Are you trying to tell me that every single test that shows improved performance with a K&N filter was a phony? I've seen so many of tests from so many different sources, that I do not think it is possible for K&N to be paying off all of them. Actually, all of those links that Byteme just posted (except for the first one) prove that a K&N is less restrictive and improves performance over paper filters.
We've gone over this a million times. A huge engine or one with forced induction may see an increase in performance, but the butt dyno isn't going to register it in most cases, and neither will your pocket book. This is particularly the case in cars with normally anemic engines. You are allowing largely unfiltered air to enter your engine, contaminating intake sensors on its way, for the sake of a very minor increase in HP. Most cars are limited by the size of the throttle body and the tuning of the engine. Changing something that far away from the real action simply doesn't have that much of an effect, and I am not willing to risk damage to my engine for the hell of it.
I noticed Z28 chimed in about his motorcycle; on a vehicle weighing 400lbs you are probably going to notice even minor changes to the power curve, but in a 3000lbs vehicle not so much.
Quote from: GoCougs on May 05, 2009, 09:09:00 AM
Yeah, I'm not sure if he was joking, or serious, trying to make a funny, or just trundling in out of boredom...
What I have read about the subject is that automakers spend quite a bit of money on intake filter/box/tract design, to take advantage of the pulsing effect of the intake charge WRT to the firing of the cylinders. This advantage is along the lines of throttle response, and otherwise maximizing performance.
The specifics are well beyond my knowledge, but it's enough for me to say I think that yeah, a team of dozens, scores, maybe hundreds of power train engineers, who are are spending tens or hundreds of millions of $$$ developing an engine, aren't going to botch the whole process with an overly restrictive air cleaner.
K&N are for intake noise, and one risks contamination and other hassles.
To counter your thoughts, many OEM's have their performance branches that are selling intakes that come with higher flowing K&N style filters. Mazdaspeed for instance uses AEM intakes and their filters.
Quote from: r0tor on May 05, 2009, 09:35:36 AM
To counter your thoughts, many OEM's have their performance branches that are selling intakes that come with higher flowing K&N style filters.
Probably because people like to buy them anyway.
Look, case in point. I drive GTOs on a regular basis here. Many have stock airboxes, many have K&N or equivalent air boxes. I can never feel the difference between them. I get lots of vehicles of all types with K&N panel filters. Guess what, same deal. I''ve never thought to myself, "Oh my, this one clearly makes more HP than the one I drove in a few minutes ago."
Did you ever have to fix one because the engine died from sucking in too much dirt?
FWIW I bought a K&N for the RX-8 because it wwas cheaper then a OEM paper filter -shrug-
Quote from: R-inge on May 05, 2009, 09:32:26 AM
We've gone over this a million times. A huge engine or one with forced induction may see an increase in performance, but the butt dyno isn't going to register it in most cases, and neither will your pocket book. This is particularly the case in cars with normally anemic engines. You are allowing largely unfiltered air to enter your engine, contaminating intake sensors on its way, for the sake of a very minor increase in HP. Most cars are limited by the size of the throttle body and the tuning of the engine. Changing something that far away from the real action simply doesn't have that much of an effect, and I am not willing to risk damage to my engine for the hell of it.
I noticed Z28 chimed in about his motorcycle; on a vehicle weighing 400lbs you are probably going to notice even minor changes to the power curve, but in a 3000lbs vehicle not so much.
I never said the butt dyno would notice, but a real dyno does. As far as the effectiveness of the filters, they are also proven less effective than paper under dry conditions, but like r0t0r said, Mazda and others seem to think they're good enough to still honor the warranty. The bottom line is, paper filters better and is cheaper than K&N, and that is why they are used on factory vehicles. If they can save $20/vehicle x a few hundered thousand, that's a lot of money, all for a filter that will cost them more to "maintain", rather than passing the expense onto the consumer to just replace it.
An OEM mazda filter costs the customer $50. They probably buy them from Fram or Puralator for $5 a piece. They then require you to change it once a year. Its rather obvious why OEMs will never go away from paper filters...
Frankly this is one of those arguments, like oil, that is more emotional than anything else. Some people "feel" better having a paper filter and a couple fewer HP, other people "feel" better having a couple more HP at a calculated risk to their engine. Do what feels best I guess, but go into it with a very low expectation. That is all I can say really.
Quote from: NACar on May 05, 2009, 09:15:01 AM
You are denying the results of thousands of tests because of a subject that you admit is "well beyond my knowledge".
Your "pulsing" effect of intake flow takes place most importantly in the intake ports and the manifold, and is almost irrelevant by the time it gets upstream of the throttle body. We're talking about air filters, not intake design. Any restriction in the intake path that is not designed to increase velocity or induce swirl is going to decrease the volumetric efficiency of the engine. K&N's flow better than paper. Period.
Interesting.
I just looked at K&N's web site. They have buried the HP gains in the information on specific filters.
I looked at 2002 Mustangs. Average about 7-8 HP at about 5,000 RPM. Big whoop, you think you will notice that? And who drives at that RPM anyway and for how long. Also note that is for their intake and filter, not just the filter.
Next I tried a 2004 RX8. They make no claims about additional HP from using their filter.
I do see that Mazda does sell intakes for about $400. There are no claims regarding HP increases and at least one for the MazdaSpeed 3 isn't legal in california. Also, no guarantee the filters perform the same as the K&N filters.
I have also yet to see a test in which K&N outfilters the OEM filters. One would think if such a test existed K&N would proudly display the outcome on it's website.
Lastly we come to the testamonials on the K&N site. I saw none where the claims were backup up with hard data. Just "wow, I bought a K&N filter and just having the filter in the trunk on the way home reduced my 0-60 times and doubled my gas mileage".
Then there is the old argument that racers use K&N filters. You bet many of them do. Most race teams worry a lot less about engine wear than winning. They want to filter out large foreign objects like birds and beer cans, not 1 micron dust. And the sponsorship money doesn't hurt the team's bottom line either.
Quote from: NACar on May 05, 2009, 09:15:01 AM
You are denying the results of thousands of tests because of a subject that you admit is "well beyond my knowledge".
Your "pulsing" effect of intake flow takes place most importantly in the intake ports and the manifold, and is almost irrelevant by the time it gets upstream of the throttle body. We're talking about air filters, not intake design. Any restriction in the intake path that is not designed to increase velocity or induce swirl is going to decrease the volumetric efficiency of the engine. K&N's flow better than paper. Period.
"Results", "tests" and volumetric efficiency however are within my area of basic knowledge.
From K&N's website (http://www.knfilters.com/powertesting.htm): "Our horsepower/torque testing is performed on wheel-based dynamometers, which measure actual brake horsepower and torque at the wheel(s) receiving power from the drive train. This is different and we believe more reliable than horsepower/torque testing done at the flywheel of an engine."
This alone invalidates all of K&N's claims, and clearly shows that they don't know what they are doing, or do know what they are doing, but are hucksters. An engine dyno provides far more reliable testing results simply because not only are the atmospheric conditions controlled, virtually all variables that affect power on a chassis dyno are eliminated - from transmission and differential oil temp (viscosity) to tire pressure to other goodies. K&N uses a chassis dyno because it is cheap and quick, and also easier to manipulate the results. Think an automaker spending $300MM to develop a new engine uses a chassis dyno? Not on your life.
And then look at this ditty: "We attempt to hold all other variables constant to generate a reliable measurement of changes in horsepower and torque on a vehicle before and after a K&N product is installed." Uh, I'm sure they do attempt to, but on a chassis dyno it's next to impossible. Atmospheric conditions? Temperature of drive train fluids? Sorry, I don't buy it. "Attempt" is a legal out because they know that they can't with a chassis dyno.
Here's another blatant error: "These plots show the median run of a specific vehicle, which had three runs with the original stock intake system and three runs with the K&N intake kit installed." With so many variables, only three runs? Anyone with basic manufacturing engineering experience would fail this test methodology in a heartbeat.
And here is Final Indictment to K&N's testing process: "The vehicles our R&D department uses for testing are loaned to us by consumers residing near our test facilities." wat?
As to volumetric efficiency, it's an extremely basic equation to determine the maximum air flow of an engine; VE% * CID displacement * RPM / 3456, and use 100% VE. A team of power train engineers aren't going to duff this. Sure, the K&N filters may flow more, but it
simply doesn't matter. A 600 cfm filter on an engine that will only ever flow 500 cfm is wasted effort in terms of power and MPG.
Take a visit to their site and you'll see they are now pimping environmental benefits (as in, throwing away fewer filters). That IMO is an indication of the dubious value proposition. I think they and others of their ilk are snake oil hucksters along the lines of grounding kits, 3000 mile oil changes, and myriad other automotive myths.
You don't think 7-8 hp + saving money on replacement filters is a good thing? I think you have entirely the wrong attitude - and that's all you have, an attitude.
Quote from: NACar on May 05, 2009, 11:23:14 AM
You don't think 7-8 hp + saving money on replacement filters is a good thing? I think you have entirely the wrong attitude - and that's all you have, an attitude.
No that's all YOU have dude.
I think you should sort out whatever it is that's putting you in a bad mood today, and then come back when you can deal with the arguments in this thread.
Quote from: GoCougs on May 05, 2009, 11:21:43 AM
As to volumetric efficiency, it's an extremely basic equation to determine the maximum air flow of an engine; VE% * CID displacement * RPM / 3456, and use 100% VE. A team of power train engineers aren't going to duff this. Sure, the K&N filters may flow more, but it simply doesn't matter. A 600 cfm filter on an engine that will only ever flow 500 cfm is wasted effort in terms of power and MPG.
Yes, thank you.
Quote from: Byteme on May 05, 2009, 11:09:06 AM
Interesting.
I just looked at K&N's web site. They have buried the HP gains in the information on specific filters.
I looked at 2002 Mustangs. Average about 7-8 HP at about 5,000 RPM. Big whoop, you think you will notice that? And who drives at that RPM anyway and for how long. Also note that is for their intake and filter, not just the filter.
Next I tried a 2004 RX8. They make no claims about additional HP from using their filter.
I do see that Mazda does sell intakes for about $400. There are no claims regarding HP increases and at least one for the MazdaSpeed 3 isn't legal in california. Also, no guarantee the filters perform the same as the K&N filters.
I have also yet to see a test in which K&N outfilters the OEM filters. One would think if such a test existed K&N would proudly display the outcome on it's website.
Lastly we come to the testamonials on the K&N site. I saw none where the claims were backup up with hard data. Just "wow, I bought a K&N filter and just having the filter in the trunk on the way home reduced my 0-60 times and doubled my gas mileage".
Then there is the old argument that racers use K&N filters. You bet many of them do. Most race teams worry a lot less about engine wear than winning. They want to filter out large foreign objects like birds and beer cans, not 1 micron dust. And the sponsorship money doesn't hurt the team's bottom line either.
So let's say with the stock filter and a cold car they do a dyno pull. Now let's say they do a dyno pull with a K&N filter but with a warm car (i.e., warm drive train fluids). There's easily 7-8 hp difference right there.
After learning of the chassis dyno test methodology to pick up variances of 1-10 hp I have no choice but to suspect that they manipulate test parameters for their own means.
Quote from: R-inge on May 05, 2009, 11:27:14 AM
No that's all YOU have dude.
I think you should sort out whatever it is that's putting you in a bad mood today, and then come back when you can deal with the arguments in this thread.
Hey, I'm not the one who declared the holy war against K&N. I call just bullshit when I see it, and your snake oil hunt is based on nothing but opinions, backed up bt contradictory evidence. For fuck's sake, it's just a damn air filter.
Quote from: NACar on May 05, 2009, 11:23:14 AM
You don't think 7-8 hp + saving money on replacement filters is a good thing? I think you have entirely the wrong attitude - and that's all you have, an attitude.
The last engine I rebuilt was the Jaguar's and the cost was about $6,000 in parts and machine work and labour. The engine develops 265 HP so 8 HP at 5,000 doesn't mean much at all; new plugs would probably give me that kind of gain. Neither does saving a couple of hundred dollars when compared with the cost of a rebuild. I'll just suffer along with an unoptimized engine while replacing the air filter annually,
knowing, not just hoping, my engine is getting properly filtered air.
Quote from: Byteme on May 05, 2009, 11:42:25 AM
The last engine I rebuilt was the Jaguar's and the cost was about $6,000 in parts and machine work and labour. The engine develops 265 HP so 8 HP at 5,000 doesn't mean much at all; new plugs would probably give me that kind of gain. Neither does saving a couple of hundred dollars when compared with the cost of a rebuild. I'll just suffer along with an unoptimized engine while replacing the air filter annually, knowing, not just hoping, my engine is getting properly filtered air.
Show me proof that K&N filters kill engines. If all you care about is keeping your engine clean, you should seal it shut and never run it. You don't KNOW anything.
Quote from: NACar on May 05, 2009, 11:48:24 AM
Show me proof that K&N filters kill engines. If all you care about is keeping your engine clean, you should seal it shut and never run it. You don't KNOW anything.
When I sent out an oil sample for analysis the lab asked me if I had a dirty or aftermarket air filter. Why did they ask? Because of elevated silicone in the OIL. If dirt from the intake can get into the lubrication system that means that there is very much an impact from poor filtration. Someone (tongue in cheek I think) mentioned that engines don't fail from being crammed with dirt. True, but grit in your oil takes out hard parts over time. Again, not worth a minor gain in performance.
If you know so much about these topics why don't you do a little more to prove your point? At this point you're a tech student lube tech. John has the actual skills to rebuild a motor to spec. Tell me which one knows more about cars now?
If you're talking about knowledge of this specific topic, at least three people have demonstrated more knowledge in this thread, you have some catching up to do.
Quote from: NACar on May 05, 2009, 11:48:24 AM
Show me proof that K&N filters kill engines. If all you care about is keeping your engine clean, you should seal it shut and never run it. You don't KNOW anything.
No probably not. :rolleyes:
I've only been doing most of my own car maintenance for 42+ years. and only have something like 1,000,000 driving miles under my belt. But I do know a fool when I see one and I do know how to critically evalaute advertising claims and real world data.
Quote from: R-inge on May 05, 2009, 11:51:37 AM
When I sent out an oil sample for analysis the lab asked me if I had a dirty or aftermarket air filter. Why did they ask? Because of elevated silicone in the OIL. If dirt from the intake can get into the lubrication system that means that there is very much an impact from poor filtration. Someone (tongue in cheek I think) mentioned that engines don't fail from being crammed with dirt. True, but grit in your oil takes out hard parts over time. Again, not worth a minor gain in performance.
If you know so much about these topics why don't you do a little more to prove your point? At this point you're a tech student lube tech. John has the actual skills to rebuild a motor to spec. Tell me which one knows more about cars now?
If you're talking about knowledge of this specific topic, at least three people have demonstrated more knowledge in this thread, you have some catching up to do.
Do we have to go there? Of course, I didn't just rebuild an engine that runs perfectly, and no, I didn't get the highest grades in the entire engine class, or any other auto classes. Obviously, I'm a complete idiot because I have a part time job at a shitty tire and lube place.
This whole argument is so typical. Once again, NONE of you guys have demonstrated any knowledge or logic to contradict anything that I've said. All you do is tear apart K&N's marketing and say that it's snake oil, and that paper must be better since OEM's use it.
What are you guys trying to argue about anymore? I already said that K&N's don't filter as well as paper. Why are you still trying to argue with me like I didn't know that? They are also less restrictive to airflow, another point that nobody here is denying. So what's the damn problem here?
Quote from: Byteme on May 05, 2009, 12:09:40 PM
No probably not. :rolleyes:
I've only been doing most of my own car maintenance for 42+ years. and only have something like 1,000,000 driving miles under my belt. But I do know a fool when I see one and I do know how to critically evalaute advertising claims and real world data.
There are a lot of people who have been doing their own maintenance for their entire lives, and they still don't know jack shit. You are trying so hard not to be a fool, but you are the fool.
Quote from: NACar on May 05, 2009, 12:37:33 PM
Do we have to go there? Of course, I didn't just rebuild an engine that runs perfectly, and no, I didn't get the highest grades in the entire engine class, or any other auto classes. Obviously, I'm a complete idiot because I have a part time job at a shitty tire and lube place.
No you're not a complete idiot, but waltzing in here and throwing around your superior automotive knowledge isn't a good call when you are outweighed in that department in the first place. I was in your place once too; some knowledge, some experience. I am still not quite where I would like to be someday (who is?) but what I am trying to say is not to make the mistake I made in assuming that tech school provides you with all the answers.
QuoteThis whole argument is so typical. Once again, NONE of you guys have demonstrated any knowledge or logic to contradict anything that I've said. All you do is tear apart K&N's marketing and say that it's snake oil, and that paper must be better since OEM's use it.
What are you guys trying to argue about anymore? I already said that K&N's don't filter as well as paper. Why are you still trying to argue with me like I didn't know that? They are also less restrictive to airflow, another point that nobody here is denying. So what's the damn problem here?
What about where you said, "Show me proof that K&N kills engines?" I answered that one already. Grit from the induction system gets on the oil on the cylinder walls, gets scrapped into the lubrication system where it can do damage before it gets filtered out.
You base your claims to higher horsepower on dubious testing techniques, as Cougs demonstrated.
Basically all your "arguments" are flotsam, but you keep coming back for more.
NACar's tirade here reminds me of the conversation I have with the local oil change shop just about every oil change - and I had one just last week.
I like a regular guy follow my car's oil life monitor. It turns on at 6500 - 7000 miles. Without fail the lube tech goes on a jihad about the 3000 mile interval, and that I'm harming my engine, and blah, blah, blah.
I usually reply, yeah, but Honda says the interval is 7500 miles. Then I get a retort along the lines of that everyone does "severe" driving according to the API so you should only go 3000 miles. I then simply reply, "but API doesn't design, build and warranty Honda's engines." Neither is it K&N's business to design and build engines.
Just reading their test methodology and their caveat language ("attempt to hold all other variables constant" or "your results will vary" or "designed to provide") plus having just a bit of basic knowledge about VE plus a bit of hand-on knowledge and experience, I feel comfortable stating that K&N's power and mpg claims are bunk.
Quote from: R-inge on May 05, 2009, 12:46:37 PM
No you're not a complete idiot, but waltzing in here and throwing around your superior automotive knowledge isn't a good call when you are outweighed in that department in the first place. I was in your place once too; some knowledge, some experience. I am still not quite where I would like to be someday (who is?) but what I am trying to say is not to make the mistake I made in assuming that tech school provides you with all the answers.
What about where you said, "Show me proof that K&N kills engines?" I answered that one already. Grit from the induction system gets on the oil on the cylinder walls, gets scrapped into the lubrication system where it can do damage before it gets filtered out.
You base your claims to higher horsepower on dubious testing techniques, as Cougs demonstrated.
Basically all your "arguments" are flotsam, but you keep coming back for more.
You don't get it. You want superior automotive knowledge? You got it. I have no problem saying that as far as I can tell, I'm the smartest person here in that department. There. I sound like a cocky asshole, but at least I tell the truth.
YOU DO NOT HAVE ANY PROOF that a K&N filter is going to cause your engine to fail or wear out prematurely. Neither of us know what amount of contaminants that a K&N lets in, or to what degree it harms or shortens the life of a given engine. Can you tell me if a paper filter will allow your engine to go an extra 200,000 miles, or just another 1,000? No. I'd like to see a test in that respect, but until then, cut the crap.
Quote from: GoCougs on May 05, 2009, 01:01:14 PM
NACar's tirade here reminds me of the conversation I have with the local oil change shop just about every oil change - and I had one just last week.
I like a regular guy follow my car's oil life monitor. It turns on at 6500 - 7000 miles. Without fail the lube tech goes on a jihad about the 3000 mile interval, and that I'm harming my engine, and blah, blah, blah.
I usually reply, yeah, but Honda says the interval is 7500 miles. Then I get a retort along the lines of that everyone does "severe" driving according to the API so you should only go 3000 miles. I then simply reply, "but API doesn't design, build and warranty Honda's engines." Neither is it K&N's business to design and build engines.
Just reading their test methodology and their caveat language ("attempt to hold all other variables constant" or "your results will vary" or "designed to provide") plus having just a bit of basic knowledge about VE plus a bit of hand-on knowledge and experience, I feel comfortable stating that K&N's power and mpg claims are bunk.
You can't even compare me to some brain washed grease monkey. Those are the types of people that I clash with on a daily basis.
Quote from: NACar on May 05, 2009, 12:37:33 PM
There are a lot of people who have been doing their own maintenance for their entire lives, and they still don't know jack shit. You are trying so hard not to be a fool, but you are the fool.
You know, this is just an internet forum and I try not to take it so seriously but having said that I'm getting tired of the petty personal insults you throw out when you run out of decent counter arguments.
Let me offer this simple suggestion. Why don't you open your eyes and read the material with an open mind. Anyone would think you are a K&N stockholder.
Quote from: NACar on May 05, 2009, 01:03:23 PM
You don't get it. You want superior automotive knowledge? You got it. I have no problem saying that as far as I can tell, I'm the smartest person here in that department. There. I sound like a cocky asshole, but at least I tell the truth.
And you base that claim on what?
Quote from: NACar on May 05, 2009, 01:03:23 PM
You don't get it. You want superior automotive knowledge? You got it. I have no problem saying that as far as I can tell, I'm the smartest person here in that department. There. I sound like a cocky asshole, but at least I tell the truth.
OK Big Guy, you officially have the longest Epeen. Happy? I hope it doesn't hurt to bad when it gets chopped off.
QuoteYOU DO NOT HAVE ANY PROOF that a K&N filter is going to cause your engine to fail or wear out prematurely. Neither of us know what amount of contaminants that a K&N lets in, or to what degree it harms or shortens the life of a given engine. Can you tell me if a paper filter will allow your engine to go an extra 200,000 miles, or just another 1,000? No. I'd like to see a test in that respect, but until then, cut the crap.
I'm sorry but in my world 2+2=4 all of the time. Dirt + metal parts = wear, 100% of the time. I doubt any such study occurs, but if I find one I'll let you know, but I'm not going to scour the internet trying to deal with your feeble arguments. I don't really care at this point to continue to argue with you, it's pointless.
Quote from: NACar on May 05, 2009, 01:05:27 PM
You can't even compare me to some brain washed grease monkey. Those are the types of people that I clash with on a daily basis.
I'm not comparing you to that guy, I'm comparing K&N - K&N is using its available means to delve into an area which isn't their expertise because they have a financial stake in doing so.
Quote from: Byteme on May 05, 2009, 01:11:23 PM
And you base that claim on what?
I base it on every single conversation that I've ever had with anybody about cars. Of course, you're old, so you think you're smarter than any younger folk. I don't like talking to people like you.
Quote from: R-inge on May 05, 2009, 01:13:45 PM
OK Big Guy, you officially have the longest Epeen. Happy? I hope it doesn't hurt to bad when it gets chopped off.
I'm sorry but in my world 2+2=4 all of the time. Dirt + metal parts = wear, 100% of the time. I doubt any such study occurs, but if I find one I'll let you know, but I'm not going to scour the internet trying to deal with your feeble arguments. I don't really care at this point to continue to argue with you, it's pointless.
Fuck your epeen. Epeen has nothing to do with anything. Go ahead and keep throwing your insults at me, I've heard it all before. I've had enough with this jackasserey.
Quote from: NACar on May 05, 2009, 01:23:12 PM
I base it on every single conversation that I've ever had with anybody about cars. Of course, you're old, so you think you're smarter than any younger folk. I don't like talking to people like you.
Fuck your epeen. Epeen has nothing to do with anything. Go ahead and keep throwing your insults at me, I've heard it all before. I've had enough with this jackasserey.
God it would be fun to sit in and watch you in your first real job as a tech. Watching you struggle because you alienate all the other guys in the shop to who have a clue with your bad attitude would be good entertainment.
The TRD airbox I got for my Elise uses green foam filters. And it was dynoed to gain about 3-5 hp, but that can be a variation with temperature, and other conditions. And most of that gain was most likely due to airbox design and not filter itself.
However, I do think most manufacturers uses paper filter rather than any type of foam cloth filters due to cost, maintainence, and liability/warranty reasons. If you have something that's cheap and easily replaced, why swap it for something where someone has to clean and could mess up doing so where the manufacturer would have to end up footing the bill for maintainence? I wouldn't.
Simple.
Go back to post five in this thread and think about the "other thing". Why oil is used as a filtration supplement.
A good tech always ask why and how something affects a vehicle. You just don't throw parts at it and assume it works.
R/C nitro and gas cars use foam filters. :praise:
That's about all I know on the subject. :huh: :lol:
Quote from: NACar on May 05, 2009, 01:23:12 PM
I base it on every single conversation that I've ever had with anybody about cars. Of course, you're old, so you think you're smarter than any younger folk. I don't like talking to people like you.
Oh, well in that case fuck off sport.
Edit:
I ask you a reasonable question about where you acquired your automotive knowledge and I get a load of crap in return. You've got a bright career ahead of you in any position where you have to deal with other people. :rolleyes:
Quote from: Byteme on May 05, 2009, 11:42:25 AM
The last engine I rebuilt was the Jaguar's and the cost was about $6,000 in parts and machine work and labour. The engine develops 265 HP so 8 HP at 5,000 doesn't mean much at all; new plugs would probably give me that kind of gain. Neither does saving a couple of hundred dollars when compared with the cost of a rebuild. I'll just suffer along with an unoptimized engine while replacing the air filter annually, knowing, not just hoping, my engine is getting properly filtered air.
$6k with your own labor?? :mask:
Damn that's expensive.
Quote from: thecarnut on May 05, 2009, 01:48:58 PM
$6k with your own labor?? :mask:
Damn that's expensive.
Parts are not cheap for that engine. Plus, only about 1/2 the labour was mine. About 50% was professional.
Machining and head work was well over a grand. New pistons, we overbored .030, were about $130 each. All the nickel dime stuff one has to buy just adds up (well over $150 in gaskets).
I find the filtration arguement halarious at best. The amount of dirt filtered between the best and worst filters are within 2%. Over the life of a engine, if it injects 20 pounds of dirt with a paper filter, I hardly think its going to care about 20.4 pound of dirt with a K&N.
However the tests posted previous do show a 1-2 inHG differential in pressure drop. In some engines thats like closing the throttle 5%.
Quote from: r0tor on May 05, 2009, 01:59:23 PM
I find the filtration arguement halarious at best. The amount of dirt filtered between the best and worst filters are within 2%. Over the life of a engine, if it injects 20 pounds of dirt with a paper filter, I hardly think its going to care about 20.4 pound of dirt with a K&N.
However the tests posted previous do show a 1-2 inHG differential in pressure drop. In some engines thats like closing the throttle 5%.
I still don't buy that coating my intake in oil that is blown off a filter is a good idea. The throttle body ultimately controls airflow to the cylinders, not the filter.
But I'll take your word for it on the filtration thing, since you seem to know something about it.
:popcorn:
Quote from: R-inge on May 05, 2009, 09:32:26 AM
I noticed Z28 chimed in about his motorcycle; on a vehicle weighing 400lbs you are probably going to notice even minor changes to the power curve, but in a 3000lbs vehicle not so much.
Honestly I can't feel any differance on either vehicle. I know on my last bike The Power Commander had a setting for K&N and exhaust set ups. I'm not sure if the filters cause that much of a change (the bikes are ram air) or not. :huh:
Quote from: R-inge on May 05, 2009, 02:03:33 PM
I still don't buy that coating my intake in oil that is blown off a filter is a good idea. The throttle body ultimately controls airflow to the cylinders, not the filter.
But I'll take your word for it on the filtration thing, since you seem to know something about it.
i had 2 cups of motor oil in my intake before i put a catch can on -sigh-
Damn, this has been an entertaining thread to read today...when I could. I couldn't reply in any detail because for once we actually got busy.
To rehash some comments here...indeed, it only take a few minutes to clean the MAF sensor. Logically though, you should ask why you constantly have to clean it with K&N, not that it is easy so it isn't a big deal. The reason for oil with K&N is to stop dirt from going any further than the filter. Ask yourself, why you do not need to do this with a paper filter.
If an air cleaner system claims less restriction (air flow) it logically can only achieve this one way...by opening up the pores to allow more air through.
Then there is the oil bath itself. Since it has been determined that the MAF will need to be cleaned, the next question is how soon? If you install a freshly cleaned and oiled filter and oil comes off the filter and contacts the MAF sensor after driving the vehicle your performance will suffer. If nothing else that small amount of oil is collecting on the platinum grid/wire and allow dirt to collect that much sooner and that much thicker which would insulate the sensor and change its readings to the PCM.
As I hinted, it isn't enough to take a manufacturer for their word. If they claim something always ask why and how. Forget bias as to why. Ask instead why and how does the filter allow more air flow and how does that affect components downstream.
Quote from: r0tor on May 05, 2009, 03:56:16 PM
i had 2 cups of motor oil in my intake before i put a catch can on -sigh-
And is your MAF before or after the PCV inlet?
Wow, that was epic.
Quote from: Psilos on May 05, 2009, 10:01:45 PM
Wow, that was epic.
I agree. Who knew?
I'm afraid of posting my decision when I go to the autoparts store tomorrow for fear of starting it again.
I've seen K&N debates before, but none where everyone was so pissy. It's another one of those things where there's not enough information available to make one side obviously right, and there's also a lot of misinformation out there. Like the oil change/type/etc. debate.
Quote from: Psilos on May 06, 2009, 12:50:21 AM
I've seen K&N debates before, but none where everyone was so pissy. It's another one of those things where there's not enough information available to make one side obviously right, and there's also a lot of misinformation out there. Like the oil change/type/etc. debate.
It would have been a fine debate if Nick didn't have to be such a troll about it.
Like I said on page one, it's an emotional decision more than anything.
Well, this is enough for me to consider putting the paper filter back in. I just liked the sound the K&N made. I don't really feel any increase in the car. I really don't like the idea of any of that oil making it in any further than staying on the filter itself. Kind of defeats the purpose of having a filter to begin with. Me and my foolish spending.. :(
Quote from: Psilos on May 06, 2009, 12:50:21 AM
I've seen K&N debates before, but none where everyone was so pissy. It's another one of those things where there's not enough information available to make one side obviously right, and there's also a lot of misinformation out there. Like the oil change/type/etc. debate.
There's plenty of info to make it a black and white issue (as all issues are): works for looks/sound, doesn't work for power/mpg...
Quote from: Northlands on May 06, 2009, 09:05:59 AM
Well, this is enough for me to consider putting the paper filter back in. I just liked the sound the K&N made. I don't really feel any increase in the car. I really don't like the idea of any of that oil making it in any further than staying on the filter itself. Kind of defeats the purpose of having a filter to begin with. Me and my foolish spending.. :(
If you want a cool sound, cut a (larger) hole in your air intake box and use a paper filter. Better effect, and free.
:rockon:
Quote from: R-inge on May 06, 2009, 07:21:39 AM
It would have been a fine debate if Nick didn't have to be such a troll about it.
Like I said on page one, it's an emotional decision more than anything.
You guys were all dicks. ;)
Quote from: Psilos on May 06, 2009, 11:39:11 PM
You guys were all dicks. ;)
Yeah you're right, I should have let him walk all over me with his incredibly strong argument. :rolleyes:
If all someone can say is "Ju dun know anyting! I R smartest!" as they throw a fit over something as trivial as an air filter then they are going to get pounced on.
Seriously, Nick, do you have K&N stock or something? I still can't wrap my head around how you would take such a vested interest in defending them.
Quote from: JWC on May 05, 2009, 04:02:42 PM
Damn, this has been an entertaining thread to read today...when I could. I couldn't reply in any detail because for once we actually got busy.
To rehash some comments here...indeed, it only take a few minutes to clean the MAF sensor. Logically though, you should ask why you constantly have to clean it with K&N, not that it is easy so it isn't a big deal. The reason for oil with K&N is to stop dirt from going any further than the filter. Ask yourself, why you do not need to do this with a paper filter.
If an air cleaner system claims less restriction (air flow) it logically can only achieve this one way...by opening up the pores to allow more air through.
Then there is the oil bath itself. Since it has been determined that the MAF will need to be cleaned, the next question is how soon? If you install a freshly cleaned and oiled filter and oil comes off the filter and contacts the MAF sensor after driving the vehicle your performance will suffer. If nothing else that small amount of oil is collecting on the platinum grid/wire and allow dirt to collect that much sooner and that much thicker which would insulate the sensor and change its readings to the PCM.
As I hinted, it isn't enough to take a manufacturer for their word. If they claim something always ask why and how. Forget bias as to why. Ask instead why and how does the filter allow more air flow and how does that affect components downstream.
Couple points here...
- MAFs should be cleaned once every year or two regardless as no matter what filter you have on, it still gets dirty no matter what.
- I clean my K&N once a year... and also take the 2 minutes to clean the maf
- Proper "recharging" of a K&N filter should utilize the absolute least amount of oil you can spray on while getting full coverage. If the filter is soaked you did it wrong. If you put a piece of newspaper behind the filter, blow some shop air through the filter, and oil gets on the newspaper - you also did it wrong.
Pressure drop across a filter is also not proportional to the ability to to filter either. A really awesome filter can have a low dp and also a high level of filtration if it is designed correctly. You can achieve this by proper material selection, careful attention to the pleat design and density of the filter, and also how it manages airflow entering and exiting the filter (in a cone type filter).
Quote from: R-inge on May 05, 2009, 04:32:59 PM
And is your MAF before or after the PCV inlet?
Mazda doesn't actually use a PCV valve in the rotary - just basically a vent from the crankcase. In my year RX8 its located near the throttle body. Enough oil collected (or was also burped) into it that oil coated and overflowed the accordion style rubber air inlet tube and oil was laying in my intake box... no real bad effect occurred except a slimy filter and intake
I made it clear that a K&N should be properly maintained. While I've read recommendations to clean an MAF sensor with every filter change, I've also have cars out that that pass MAF tests with over 150,000 and the MAF has never been cleaned.
I've also seen demos of air filters at auto shows and it is eye opening how much dirt gets pass a K&N.
Quote from: r0tor on May 07, 2009, 04:58:20 PM
Couple points here...
- MAFs should be cleaned once every year or two regardless as no matter what filter you have on, it still gets dirty no matter what.
- I clean my K&N once a year... and also take the 2 minutes to clean the maf
- Proper "recharging" of a K&N filter should utilize the absolute least amount of oil you can spray on while getting full coverage. If the filter is soaked you did it wrong. If you put a piece of newspaper behind the filter, blow some shop air through the filter, and oil gets on the newspaper - you also did it wrong.
Pressure drop across a filter is also not proportional to the ability to to filter either. A really awesome filter can have a low dp and also a high level of filtration if it is designed correctly. You can achieve this by proper material selection, careful attention to the pleat design and density of the filter, and also how it manages airflow entering and exiting the filter (in a cone type filter).
I agree that the MAF should be maintained, as long as the manufacturer is OK with you spraying it with chemicals. I also agree with correct filter service being hugely important. However, I still reject the idea of using something that can contaminate the MAF sensor in the first place. Paper filters simply do not run that risk, and as JWC pointed out most vehicles go their entire lives without a MAF cleaning, with zero driveability concerns. Additionally, more dirt let through outweighs even a small gain in power, no matter how small the amount of dirt or how big the power gain (realizing here that an air filter alone won't give you huge results).
Quote from: r0tor on May 07, 2009, 05:01:57 PM
Mazda doesn't actually use a PCV valve in the rotary - just basically a vent from the crankcase. In my year RX8 its located near the throttle body. Enough oil collected (or was also burped) into it that oil coated and overflowed the accordion style rubber air inlet tube and oil was laying in my intake box... no real bad effect occurred except a slimy filter and intake
That's odd that the Mazda allows oil to drip into the air box. But my point is not that I am concerned about oil entering my intake; clearly the PCV system takes care of that for me. My concern is instead that oil should enter the airstream upstream of the MAF sensor. But the MAF sensor is not in line with that oil source normally, hence is never contaminated on most vehicles.
MAF sensors can also be contaminated by poorly fitted paper filters, torn filters, filters eaten by rodents, or those that are clogged and end up deforming due to vacuum and allowing dirt through. There is no perfect solution, but the best is a properly fitted paper filter as far as I can tell. When someone comes up with a filter and works as well, is dry, and also flows better I will give it a shot. I hear Amsoil came up with just such a design.
AEM has a "dry Flow" filter for a few years now. For the record, when I replaced my stock airfilter with the K&N after a year of use, my MAF was jut a dirty -shrug-
All the tests linked on page 1 show the filtering efficiency being 96-97% vs 98-99%. The amount of dirt passed is only significant if you scale a graph creatively.
Quote from: r0tor on May 08, 2009, 05:58:17 AM
AEM has a "dry Flow" filter for a few years now. For the record, when I replaced my stock airfilter with the K&N after a year of use, my MAF was jut a dirty -shrug-
All the tests linked on page 1 show the filtering efficiency being 96-97% vs 98-99%. The amount of dirt passed is only significant if you scale a graph creatively.
Then it boils down to do you want a filter that allows double the dirt to pass to the engine, oils the MAF sensor, and requires periodic maintenance involving time and additional expense for a gain of half a dozen HP at or near the redline. Or do you want the convenience of a disposable filter and double the filter effectiveness at the expense of half a dozen HP at or near the redline.
As has been pointed out it's largly a personal choice. I'll opt for the paper filter.
I think what R-inge and others, including myself, have been pointing out is the K&N's are not the wonder filter that does everything well. They are a trade off, like just about every thing else in life. Hence the challenge to their claims which only point out the virtures.
Quote from: Byteme on May 08, 2009, 06:26:07 AM
Then it boils down to do you want a filter that allows double the dirt to pass to the engine,
Again a reality check.... "double" is creative math and double of next to nothing is still next to nothing. Its like telling your child who got a 96% on their math test that they did "twice as bad" as a classmate who got a 98% on the test because they got 2 questions wrong on a 50 question test while the other person got 1 question wrong. In reality, they came within 2% of each other in getting things right.
In the real world with changing your paper filer once a year, your lucky to have .5 pounds of dirt caught in the worst case (think about the weight of a dirty filter vs a new one...). That means it had to filer .505 pounds of dirt, it caught 99% or .5 pounds, and left through 1% or .005 pounds. If you had a K&N filter, it would have caught .49 pounds of stuff and let through .015 pound.
The real difference is a hundredth of a pound of dirt!
Quote from: r0tor on May 08, 2009, 08:35:22 AM
Again a reality check.... "double" is creative math and double of next to nothing is still next to nothing. Its like telling your child who got a 96% on their math test that they did "twice as bad" as a classmate who got a 98% on the test because they got 2 questions wrong on a 50 question test while the other person got 1 question wrong. In reality, they came within 2% of each other in getting things right.
In the real world with changing your paper filer once a year, your lucky to have .5 pounds of dirt caught in the worst case (think about the weight of a dirty filter vs a new one...). That means it had to filer .505 pounds of dirt, it caught 99% or .5 pounds, and left through 1% or .005 pounds. If you had a K&N filter, it would have caught .49 pounds of stuff and let through .015 pound.
The real difference is a hundredth of a pound of dirt!
Well, a considering how hot the rotary runs, how much of that dirt would be burned off anyways. As long as the big particles are not going through, I don't see it being an issue especially with the oil change requirements with the Wankels.
Screw it, stick with ram pipes.
Quote from: Psilos on May 08, 2009, 09:33:41 PM
Screw it, stick with ram pipes.
Velocity stacks? Yeah, I'm ok with that. :lol:
Quote from: r0tor on May 08, 2009, 05:58:17 AM
AEM has a "dry Flow" filter for a few years now.
That's what I'm going to be getting. I don't have the original air filter box (previous owner discarded it I guess), so it has to be a drop-in filter of some sort. I've read really good things about the DryFlow, it's no more expensive than a K&N, reusable, dry, and avoids the K&N conflict. Haha.
The K&N filter oil is really, really sticky. I was re-oiling mine in a stainless steel kitchen sink, and I had to use some of the cleaner fluid to get it to come off of the metal. It's not like cooking oil that would come flying off in half a mile.
Quote from: GoCougs on May 05, 2009, 09:09:00 AM
What I have read about the subject is that automakers spend quite a bit of money on intake filter/box/tract design, to take advantage of the pulsing effect of the intake charge WRT to the firing of the cylinders. This advantage is along the lines of throttle response, and otherwise maximizing performance.
I havne't read teh entire thread, but here's my take on this statment.
If this was true, and they spent gobs of money maximizing performance of the air intake, then why do they NEVER maximize performance in any other part? If your statement was true, then how much power a stock engine makes is the total amount of power it can EVER make, and no one ever ported and polished their way to improved hp. Because those factory engineers spent way more money and are way more educated than any hot rodder.
No, manufacturers maximise the compromise of cost, NVH, and waranteeability.
Quote from: ChrisV on May 14, 2009, 11:03:19 AM
I havne't read teh entire thread, but here's my take on this statment.
If this was true, and they spent gobs of money maximizing performance of the air intake, then why do they NEVER maximize performance in any other part? If your statement was true, then how much power a stock engine makes is the total amount of power it can EVER make, and no one ever ported and polished their way to improved hp. Because those factory engineers spent way more money and are way more educated than any hot rodder.
No, manufacturers maximise the compromise of cost, NVH, and waranteeability.
But the the impetus still falls on K&N and its defenders to explain the "compromise" behind the design/specification of an air filter that would rob and engine of power and MPG.
Quote from: ChrisV on May 14, 2009, 11:03:19 AM
No, manufacturers maximise the compromise of cost, NVH, and waranteeability.
+1
Or tuners wouldn't exist and aftermarket or performance parts wouldn't exist.
(But I will probably never even try "cleanable" filters..)
I used K&N on a number of my carburated cars, especially when the rest of the engine is built up, as they do flow more air for longer periods of time. I've known people that have had problems on MAF equipped cars with oil contamination, and others that have never had MAF contamination with K&Ns, so it may be a case of proper vs improper oiling of them. Personally, on a MAF equipped street car, I'd rather replace paper filters more often than take the chance that I put a little too much oil on one time and mess up the MAF.
As an aside, I've used a similar filtration system on paint booths before, where the exhaust air is blown across a water trough, and the paint particls stick to the water surface while teh air itself bounces off and continues. It's more effective than just a filter. Supposedly, the K&N works similarly. The air doesn't go straight through, it tends to bounce off the oil coated fibers, where the particulate sticks and the air continues on. Unlike paper filters, where the size of the hole is what traps the particulate, so the voids have to be smaller and slightly more restrictive, the oil in the K&N does the trapping, so the voids in the filter can be larger and less restrictive to the air without having to worry about larger particulate getting through.
Quote from: ChrisV on May 15, 2009, 07:55:44 AM
I used K&N on a number of my carburated cars, especially when the rest of the engine is built up, as they do flow more air for longer periods of time. I've known people that have had problems on MAF equipped cars with oil contamination, and others that have never had MAF contamination with K&Ns, so it may be a case of proper vs improper oiling of them. Personally, on a MAF equipped street car, I'd rather replace paper filters more often than take the chance that I put a little too much oil on one time and mess up the MAF.
As an aside, I've used a similar filtration system on paint booths before, where the exhaust air is blown across a water trough, and the paint particls stick to the water surface while teh air itself bounces off and continues. It's more effective than just a filter. Supposedly, the K&N works similarly. The air doesn't go straight through, it tends to bounce off the oil coated fibers, where the particulate sticks and the air continues on. Unlike paper filters, where the size of the hole is what traps the particulate, so the voids have to be smaller and slightly more restrictive, the oil in the K&N does the trapping, so the voids in the filter can be larger and less restrictive to the air without having to worry about larger particulate getting through.
So in conclusion, the K&N filters should work theoretically without causing additional harm to the engine but only if it is used properly. And the reason why manufacturers don't use them is because they have to base their warranty of proper usage of the item which is too big of a risk to them. Cheaper and safer with paper.
Quote from: NomisR on May 15, 2009, 11:30:33 AM
So in conclusion, the K&N filters should work theoretically without causing additional harm to the engine but only if it is used properly. And the reason why manufacturers don't use them is because they have to base their warranty of proper usage of the item which is too big of a risk to them. Cheaper and safer with paper.
Certainly a plausible summary.
I tend to agree with ChrisV that using them on a carbeurated car probably isn't a problem at all.
How difficult is it to properly inspect and clean my MAF sensor? Do I have to take it apart?
Quote from: Laconian on May 15, 2009, 12:20:35 PM
How difficult is it to properly inspect and clean my MAF sensor? Do I have to take it apart?
Kind of. Some cars it's easy to get the sensor out, and some cars you can do it after just taking the airbox and tube off...
(http://www.crcindustries.com/catalog/images/Cleaners%20and%20Degreasers/05110.jpg)
Here's the hard way: http://www.louv.tv/cars/m5/MAF/
Here's the easy way: http://www.bimmerboard.com/forums/posts/343329
mines just in with 2 phillips head screws... disconnect the plug, unscrew the 2 screws, and out it pops
Quote from: Laconian on May 15, 2009, 12:20:35 PM
How difficult is it to properly inspect and clean my MAF sensor? Do I have to take it apart?
On our cars, you just unplug it and remove it from the elbow and the crossover tube. There's kind of a "bullet" shape in the center; on the side that faces towards the front of the car you can see the MAF wires.