K & N

[donDavide]

World Impex

Maybe keeping things in perspective will help. Look at this way: the service manual says air filters should be changed at 40K miles. Just because the filter "looks" dirty doesn't mean it's time to change it at 5k. And those monkeys at Jiffy Lube shouldn't even touch it, but that's another story.

Anyways, at around 40K you pick up a brand-new OEM filter for a whopping $13, which is good for another 40K. So if your engine lasts you 250,000 miles and you don't crash the car or sell it in this time, you'll have spent $82 on just air filters.

Using the K&N filter, you have to figure in the cost of at LEAST one bad MAF caused by the oil. Sure, you could have the MAF go out using the stock paper one as well. But how much more at risk is the MAF with more dust and dirt particles slamming into it? More air flow means less resistance, i.e. filtration.

So you pay the $45 for the K&N, and you buy the $12 recharge kit which is good for about 2-3 uses, tops. Except that to keep the filtration at the best level it can be for the K&N, it needs to be cleaned and reoiled more often than 40K miles. Otherwise you're just letting in all kinds of debris into your engine and turbo, which is like sand in private parts, as DB wittily pointed out.

Not only does the K&N filter not seal perfectly well, unlike the OEM filters which are meant for one-time crush foam seal, but you also spend more on cleaning and recharging, not considering the down-time while you wash it, dry it, oil it and replace it. Add to that poorer filtration at the cost of more flow, which your turbo more than compensates for btw, and you've got an expensive oily mess that will only cause problems sooner or later.

Why chance it? For the 1hp it adds or 5 lbs/ft of torque you just swear you can feel? Turbos are anywhere from $500 and up, MAFs from $120 and up. Why spend $45+$12= $57 for an extra factor to worry about?

Run OEM, change every 40K unless you live in AZ, keep your money for other things. My 2 pennies' worth, anyway.

World Impex has Mann for $6.52,Mahle for $8.52, and OEM VW for $16. of course there is frieght (mine is giving a 6 pack to a coworker to p/u 4 me) but the more more you buy the less expensive it is per unit, signifigantly). I am ditching my K&N filters for Mann. Even Pat Goss of Motorweek, Goss's garage, On Maryland Public Television (MPT) and on Speed Channel says the the aren.t worth using because the engine will get the air it was meant to have.

 

[WB9K]

I started a really long response, but here are my major beefs with your post.

1. I can say that I found a study that the moon is made of cheese...that doesn't mean that it really is. See #4.

2. With regards to the abstract (not even the whole paper ), you missed my point; filters HAVE to be evaluated seperately from intake systems in order to isolate the parameters in question. You don't even know exactly what the experiement did because there is no procedure section available so that someone like me could duplicate it. Please post full papers or nothing as this link is essentially useless to me (nothing I didn't know already). I would be willing to bet a large amount of money that one type of filter media was used in the entire experiement (the tip-off is in the first sentence, no less).

3. Also, whether or not a test uses the latest technology or not doesn't matter as long as the math works and the measurements are taken with enough accuracy and consistency to minimize error in the results. Laser Doppler anemometers are cool, but you don't need them to find out if one type of air filter out performs another.

4. I read your other links; one measured horespower increase and filtering ability, the other just filtering ability. NOT ONE of the links you posted had the k&n come out on top, in flow or in filtering performance. Thank you for making my point (well, our point) valid with your links, and for shooting holes in your argument. I didn't even have to work at it.

I use glorified leaf blowers all the time to measure things like airfoil performance and pressure drop through ducting; they work just fine for pulling air.

Dale: dittos on what ruking said. Way to step up.

Response to each point:

1) You're exactly right. This has been one of the main points I have been trying to make all along. The only good approach to all the data out there is to read as much of it as possible and try to weigh the credibility of each test and go with the stuff most relevant to your own particular needs.

2) All I said was that the abstract states quite clearly that even without looking at filters, intake system geometry can have a profound impact on airflow. I was also disappointed that more info was not available on the details of the experiment, but I felt that the brief summary was worth consideration given that most of the tests cited so far were not performed in TDIs, the vehicle of interest here. So what if they did use only one filter? Who knows what kind of impact the addition of that variable will have? I don't, do you? You say the link is useless. I disagree.

3) Surely you're not suggesting that a test measuring the fairly small differences in air pressure we're talking about is just as credible from hardware store equipment as it is from NIST-certified calibrated high-precision equipment. What in the leaf-blower link makes you so sure that the accuracy and consistency was indeed good enough?

4) I read the results just like you did and I know what they say, thank you. One of them didn't use a paper filter at all, and since our discussion is primarily one of paper-vs-K&N, I don't see how that makes your point at all. I cited those reports for a couple of reasons: A) Both showed VERY clearly (IMO) that oiled foam filters A LOT worse than oiled guaze. So much for the validity of the "daylight test" so many here have touted. B) We all agree that oiled gauze does not filter as well as paper. However, the "500 mile" study shows that it does filter ALMOST as well. My question then is--how good is good enough? It's certainly NOT true that paper stops everything and oiled gauze passes everything. I assumed most here would be smart enough to figure all that out, but maybe I was wrong.

I stand by my assertion that the VAG-com measurements are probably the best possible way to resolve or render moot this whole debate wrt TDI's. Do you disagree?

It appears you have edited your post so that you are no longer asking me to present my credentials or accusing me of spreading misinformation--something I vehemently assert I have not done. If you really do want my credentials, I'll be happy to give you the long version--and it is long. I have a bachelor's degree in an unrelated field, but I have worked with some of the leading lights in a couple of different disciplines. The lone fact that you're working on a technical degree means very little to me. I couldn't even tell you how many BSEE's and MSEE's I've encountered who couldn't even read a schematic. It's scary. IME, degrees are very overrated. There isn't much you can learn in school that you can't learn on your own. There is a WHOLE LOT to be learned in the real world that can never be learned in school. That's been my experience, anyway.

Cheers,
dh

 

[ruking]

..."There is a WHOLE LOT to be learned in the real world that can never be learned in school. That's been my experience, anyway. "...

Funny how difficult it was for one to convey the learning from the orignial "REAL LIFE" example of a "K&N filter gone BAD".

I got to tell you, that your discourse was NOT a good marketing effort, that would entice (me) a consumer to try an oil media product, especially in a TDI. Did it convince YOU?

 

[ymz]

Well, my take on all this...

It's a great example of how someone new to this site is trying hard to get on people's "ignore' list...

Y.

 

[greengeeker]

Well, my take on all this...

Gee, I wish I had a 30" monitor so I could read this thread.

 

[WB9K]

..."There is a WHOLE LOT to be learned in the real world that can never be learned in school. That's been my experience, anyway. "...

Funny how difficult it was for one to convey the learning from the orignial "REAL LIFE" example of a "K&N filter gone BAD".

I got to tell you, that your discourse was NOT a good marketing effort, that would entice (me) a consumer to try an oil media product, especially in a TDI. Did it convince YOU?

Nothing I've said here has been a marketing effort for anybody. How that isn't obvious is beyond me. I'm just trying to get good solid info on which to base a simple decision.

As for the "real life example" at the beginning of this thread, several here with far more hands-on experience with cars than me have also chimed in to say what I thought was very obvious--there was a lot more wrong with that picture than an air filter element. So much more in fact that the "example" doesn't really mean anything at all in the context of this discussion. Attempt to ridicule me over that if you feel you must. It hasn't worked yet, and it isn't going to.

dh

 

[andreigbs]

What more can be said against using K&N air filters than already has been said countless times? It isn't worth the added expense and work involved with cleaning and reoiling, not worth the risk of early MAF failures and possible dirt ingestion into the turbine, no significant improvement over stock setup.

If it flows more air it means it's filtering less. You can't have better filtering with more airflow, unless you upgrade the turbo.

Simply put, K&N may help anemic domestic (and some import) gassers get a little extra more airflow and noise, which to the driver means power, all the while filtering less efficiently. No such filter is recommended or acceptable in finely-tuned and engineered TDI, or any turbocharged car with MAF sensors, IMO.

Why are we even debating with the man? He's the one who wants evidence and facts, let him go find them himself. Most everyone here already knows and accepts what DB and others have said and shown regarding K&N. There are those people who will always swim upstream.

*Edit: Even worse, this discussion keeps his posting count climbing, and i hate to think he'll be a "veteran" any sooner.

 

[ruking]

Nothing I've said here has been a marketing effort for anybody. How that isn't obvious is beyond me. I'm just trying to get good solid info on which to base a simple decision.

As for the "real life example" at the beginning of this thread, several here with far more hands-on experience with cars than me have also chimed in to say what I thought was very obvious--there was a lot more wrong with that picture than an air filter element. So much more in fact that the "example" doesn't really mean anything at all in the context of this discussion. Attempt to ridicule me over that if you feel you must. It hasn't worked yet, and it isn't going to.

dh

It is more than obvious that it is hard for you to make a simple decision. It was also obvious a lot more was wrong with the (car) whose pic was taken with the oil filtered media air filter. Matter of fact, DBW went on to say what they were.

No attempt to ridicule you, at all. You do that all too well by yourself! Again, I would not use an oil filtered media. Would you? Or will you continue to ignore the question?

 

[otbBlaine]

WB9K,

You're right; I edited my post calling you out for your credentials because I read more of your posts and decided that you must have an technical education in some field. It was late last night when I arrived home from work and after re-reading my post this morning, I sounded quite arrogant. Suffice to say, I work with this material every day; I'm quite familiar with it and know it well. I'm simply going to answer your questions and move on.

First, I don't like your Vag-Com test because a side effect of using an oiled cotton filter element seems to lead to the destruction of the very sensor you want to use to measure filter performance.

Second: if you don't understand why the abstract you linked doesn't apply to this discussion, then I don't know what else to say. It's also only part of a much larger technical paper and I simply cannot accept it as a source.

Third: as long as an experimental apparatus is well designed, you can get very credible results from it. We put people on the moon with slide-rules and caffeine, not pentium computers and CFD. I feel that the leaf-blower test in question was well designed and well conducted, so I put faith in it.

Go run your test, I think we'd all like to see your results.

 

[Drivbiwire]

Of course what he will find is that the turbo and ECU compensate for flow thru the filter and the readings will be nearly identical.

The only meaningful test is to measure the actual airbox pressure in which case I have already provided it for the different versions of the TDI airbox and cold climate filters.

Make a manomter and knock yourself out, frankly it does not matter where the filter gets different pressure gradients. Also having different areas of the filter with more flow than another aid in particle seperation as the filter accumulates dust and dirt by vitrue of the air having to travel further accross the box allowing for gravity draw heavier particles to the bottom of the filters box.

Getting back to reading the "detected" airflow, this simply tells you what the ECU is seeing not what is actually occuring in the airbox in which case I refer you to manometer readings from the clean side of the filter. This is the root of the MAF sensor issues in that as MAF sensors develop greater amounts of "error" by virtue of sensor surface damage your "IQ" ie Injection Quantity drops reducing actual engine power output.

DB

 

[WB9K]

WB9K,

You're right; I edited my post calling you out for your credentials because I read more of your posts and decided that you must have an technical education in some field. It was late last night when I arrived home from work and after re-reading my post this morning, I sounded quite arrogant. Suffice to say, I work with this material every day; I'm quite familiar with it and know it well. I'm simply going to answer your questions and move on.

First, I don't like your Vag-Com test because a side effect of using an oiled cotton filter element seems to lead to the destruction of the very sensor you want to use to measure filter performance.

Second: if you don't understand why the abstract you linked doesn't apply to this discussion, then I don't know what else to say. It's also only part of a much larger technical paper and I simply cannot accept it as a source.

Third: as long as an experimental apparatus is well designed, you can get very credible results from it. We put people on the moon with slide-rules and caffeine, not pentium computers and CFD. I feel that the leaf-blower test in question was well designed and well conducted, so I put faith in it.

Go run your test, I think we'd all like to see your results.

OTB,
Thanks for the clarification and explanation of your edit. I've posted things on the web and regretted it later, I know how it goes. It's cool, no harm, no foul. Yours is a reasonable position, and sometimes reasonable people disagree as I'm sure you have found. I may well be off base in some of my assumptions. If I thought I already knew it all, I wouldn't be here asking questions. I have learned a few things in this thread in between the barbs and insults. In the end, I expect to find that the question of greater flow will be moot because the TDI engine appears to already have more air available to it than it needs. The VAG-com should make that easy to prove beyond a reasonable doubt. I'll have to get a Mann filter and of course do that part of the test last so the one time seal will still be good when the test is over. If nobody knows a good local source in the NW Detroit burbs, I'll check out the mail-order source listed up the thread. The results will be posted in the best format I can muster, no matter what the results show.

With that, I hope to find that I have nothing left to say in this thread.

Take care,
dh

 

[Dale Seiler]

I think that DBW and others providing research data proves to me that the use of a K&N filters in the TDI provides no real benefit to the engine and the information is a major reason I will not run the filter in a TDI.
1. I have seen the replacement K&N filter at the auto parts store, they had one in stock. The filter is only about one inch thick and will plug sooner and have to be cleaned more often.
2. I believe the filter to be almost adequate in it's ability to filter. I noticed there are small holes you can see with the naked eye when held up to the light. Those holes would fill up after passing some dirt to the engine.
3. I think the biggest problem with the K&N filter to be the re-charge process. Too much oil added by the service person doing the re-charge process. This oil as pointed out by DBW will migrate to the MAF. He has also pointed out how delicate this sensor is.
4. I have run the K&N filter in other vehicles with no real problems but none of them have the MAF sensor. My truck has a manifold pressure sensor that reads off the waste gate tubing and is not effected.
I believe that the people who have chosen to run the K&N run the risk of damaging the MAF if they over oil the filter. I believe the use of a stock filter to be the best choice in this vehicle application. I believe I would rather run a stock filter with a filter-minder to tell me when I need to change then out then cleaning a K&N every 10,000 miles. Yes the K&N in my truck went only 10,000 before it needed a good cleaning.
Thanks to all for posting info on this thread.
It has sure changed my mind about some filter applications

A question?
Is there a published micron size for the stock filter and is there a published micron size for the K&N?