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Hello guys,
I see a few of you sporting K&N air filters and I wanted to share some information I’ve learned in my years of collecting exotics and some not so exotics. I presently own three Porsches (all vintage wasserpumpers), two Volvos, a TVR, and an Italian exotic investment grade automobile.
After purchasing two K&N air filters I eventually ran into a friend on a forum who had a car just like mine. It happened to be a 1983 928S 5-speed. I recommended a K&N air filter to him, and I received a surprising response from a Mr. Wally Plumley, former NASA Engineer, holder of two speed records at Bonneville Salt Flats, and presently associated with the reputable firm of 928 Specialists. http://www.928gt.com/928GT.htm
Wally advised me that they won’t sell the K&N air filter (any more) for three reasons: too much dirt gets through them, they don’t add any power to a 928, and they got way too many calls regarding drivability problems stemming from the oil on a K&N getting into the MAF system.
Upon hearing the news from a complete stranger at the time, I naturally question his information. He was polite, but firm. I checked independently, and found he was right. I am therefore sharing this information with this particular forum, along with a couple of links for your reading enjoyment.
In the end, I burned my K&N filters ceremoniously, and I took photos, ha ha. Since I have a variety of my cars published, some with engine shots sporting a K&N air filter, I’m trying to get the “word” out, that these filters will do damage to your fine machinery, and anyone (such as me) is a victim of the K&N marketing program if you bought one. I consider myself a “sucker” for having bought one, but now I know better, and I’m running “premium” paper filters that I buy from “reputable” firms such as 928 Specialists. I’m not in the automotive business, I’m just an enthusiast. I have no reason for posting this information, other than to spread what I believe is good information. Pay particular attention to the link where the racing team experienced premature leakdown problems. Then if you care to still debate, you should get in contact with the gentleman who races a FE Ford (427) who also runs a fleet truck line. He decided to try the K&N air filters to see if he could get better gas milage. The results were no additional gas milage, and increased silica (the equivalent to fine sand) in his oil analysis program. He stopped using the K&N filters and the silica readings on his oil analysis dropped.
I question the use of a K&N air filter on street machinery for several reasons. One, they are often used in a “cone” assembly, and all this does is place the air intake behind the radiator where it will suck hot air, and this is bad for performance. Two, why would I want to get zero to nil performance gain, as documented by many a dyno test, and then subject my fine machinery to additional dust ingestion?
I also have to question the motives of people who sell these filters to people who are going to use them on street driven vehicles. Certainly the motivation has to be profit. However, in the instance of 928 Specialists, they put profit aside due to what they believe is “better information” and what I call integrity.
Street driven vehicles normally have air boxes and filters sized far in excess of what the engine needs for cfm in the first place, and this is the reason we see zero horsepower difference from a dyno most of the time. For performance applications, where a 944 Porsche, for instance, has been tweaked for GTU competition, then yes, you will need something that flows better, lets more dirt and small bugs in, lets the motor develop that 600-hp for the duration of the race, and then needs to be torn down for new rings, valves, and bearings.
Submitted in good faith, for your reading enjoyment
Mr. P
http://forums1.roadfly.org/porsche/forums/924-944-968/4959457-1.html
http://forums1.roadfly.org/porsche/forums/cayenne/5147399-1.html
http://www.mcagraphix.com/filter/test.htm
http://www.performanceoiltechnology.com/k&nbitesthedust.htm
This is a test by AMSOIL, and I use their oil but not their filter. It is interesting that this test shows the paper air filter flowing better than the K&N and filtering out more dirt. I view this as just one more piece of evidence in which to make a decision.
--
2004 XC90 2.5T AWD, 1990 944 S2 Cabriolet, 1989 740 GL 16v, 1984 944, 1983 928S 5-speed, 1974 TVR 2500M
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Thanks for the interesting article.
I checked into those at one time and actually found that it would take an enormous amount of time(filter cleanings) before any kind of payback would result from using these filters.
For the money one would save...my time to install a stock filter(1 minute)is worth more than having to launder a filter and reoil it.
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posted by
someone claiming to be Sam
on
Thu Jul 8 23:53 CST 2004 [ RELATED]
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I also use K&N filters but as you've mentioned, they do not ADD HP. That notion assumes that a stock air filter restricts air flow thus potential HP. A dirty stock air filter does restrict air flow. Another myth is the notion that some brands of spark plugs somehow ADD HP, also not possible.
As for engine wear, unless one drives behind other cars on dusty roads often I wouldn't worry about whatever might slip past a clean, oiled K&N filter despite any claimed test results. I tend to think that whatever is that fine and makes it into the combustion chamber is more likely to simply pass through w/o realistically wearing out cylinder walls and piston rings. Also realize that most engines that are maintained by frequent oil changes (not neglected) usually last longer that the time, mileage that most people ever keep their cars.
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posted by
someone claiming to be DG
on
Thu Jul 8 07:35 CST 2004 [ RELATED]
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This is not new information. It has been suggested in many forums that K&N filter use can lead to increased engine wear. I have not seen hard evidence of this. I myself just had an oil test on my 1995 Subaru Impreza with 185000 miles on it and 4350 on the oil. It showed a silicon level of 10 (normal is 9) and the report from blackstone lab suggested, "Silicon was okay at 10 ppm, though you might be able to bring this number down by changing the air filter."
BTW, engine wear parameters were fine otherwise!
It is also well know that the MAF sensor can be harmed if too much oil is applied on the filter and gets "blown" off into the intake. This is associated with cleaning and reoiling, not from use out of the factory packaging.
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it may not be "new" to you, but it's new to those who haven't seen it yet, and I suspect there are many.
If your oil analysis showed a silicon content that received the comment "you might be able to bring this number down by changing the air filter" I would consider that a smoking gun.
Silicon that gets to the oil, obviously has passed by the rings, or somehow up into the (intake) valve guides. None of that sounds like "the best" care to me if your oil analysis people are even mentioning the air filter to you.
I suspect the info I posted will gain a negative reply from some people like me. Personally, I was rather disgusted with myself after I found out I had been "screwed" so to speak, by the fact that I was using a filter that admitted more dirt (and did nothing in the way of performance).
As for the reuse economics, I can't argue with that. I do know the re-oiling is a source of MAF failures and problems, because apparently people tend to over oil thinking "more is better".
In the end, it's our car, our money, and our choice to use the available information to choose the product that works best for our own situation. If you maintain a K&N properly it will provide good service and perhaps save some replacement dollars. The dirt issue is what bothers me though, and what bothers me even more, are the firms who sell these things under the guise of "increased performance", often with fancy cone filter assemblies located "behind the radiator" (LOL) for sometimes as much as $400 or more. Those people, in my opinion, are unethical, based on my simplistic view of the universe.
I appreciate your comments.
Hey, all the best to you
Mr. P
--
2004 XC90 2.5T AWD, 1990 944 S2 Cabriolet, 1989 740 GL 16v, 1984 944, 1983 928S 5-speed, 1974 TVR 2500M
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Most folks who know better agree that installing a K&N Filter will not improve performance, increase HP, or make your car run better. What folks who know better do agree on however, is that the ability to re-use a filter time and time again using their method of cleaning and oiling does indeed save you money over time. That's why I will continue to use K&N filters. Your comment on the effect of MAF sensors does intrique me however!
Thanks for the info.
--
'82 240DL Stock / Masters Class, '94 850 Fully Loaded / Daily Driver, CVC / VCOA Member http://www.capcan.com/tonyg.htm
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I see who I suspect are mostly kids, buying expensive cone filters and billet aluminum housings to rebuild a perfectly good airbox (usually with a K&N filter as part of the kit) under the guise of "increased performance". These are normally located behind the radiator where they will suck in hot air (LOL).
In addition to probably producing "less" power, these good people are actually installing a filter that has been fairly well proven to admit more dirt. Now having spent all that money, that really doesn't appear to be such a good deal. As for the money saved over the cost of a paper filter, one has to make a descision if the re-oiling kit cost + the initial filter + the additional dirt is = or better than the convenience of the paper filter with equal over-the-road performance, superior filtering of dirt, and perhaps some small measure of additiional cost.
When I make this evaluation for the machinery I'm running, I don't mind the small addl cost of the paper filter, as I'm not interested in saving a few bucks on a car that cost $50,000 in 1983, or one that is now valued close to the same value as a North American Rockwell Saberliner on the used jet market. "Any dirt" on those cars is too much dirt.
I appreciate your comments, each of us must make a decision regarding what is best for our own situation. In the end it's our car, our money, and our choice. I offer this info to assist in making that choice. I do know for a fact that the recharging of the K&N has lead to a lot of grief for people who think "more is better" and end up with too much oil on the foam. Also, once that foam gets caked with dry dust, it no longer filters "anything", so it's important to constantly monitor and assure your K&N has an oil film.
Sincerely,
Mr. P
--
2004 XC90 2.5T AWD, 1990 944 S2 Cabriolet, 1989 740 GL 16v, 1984 944, 1983 928S 5-speed, 1974 TVR 2500M
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Well...that was a damm fine read!! Thing is i have just ordered a K&N air filter for my 2002 V70.I think my first job in the morning is to cancel that order.I was a bit sceptical,but thought that i would give it a try....well no more,i will stick with my volvo service paper filter and like you say,i have paid quite a few thousand pouds for my motor and a few quid at the service is well worth it!! I will stick with the paper one!!I think that volvo invest millions in thier car designs etc..etc so if K&N were that good wouldnt volvo put them in as standard? Thanks for the push in the direction of sensibility!! Now what else can i spend £40 on?????
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changing your oil more often...i had a peugeot 405 that did 300k miles on that formula...mantra change your oil, change your oil, change your oil
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changing your oil more often...i had a peugeot 405 that did 300k miles on that formula...mantra change your oil, change your oil, change your oil
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