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K&N Observations from SCCA F500 (very long) Posted by TonyJ [Email]  (#407)  [Profile/Gallery]
(more from TonyJ) on Sat, 11 Feb 2006 20:25:02
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I found the K&N discussions interesting, so I posted a link on an automotive mailing list (Formula 500 SCCA- 2-stroke snowmobile drive train race cars) that I belong to. I use K&N on my race car and my Acura RS-X TypeS, but not on our 2 Saab 9000s. Following are some responses:
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Can't say anything about the "no power increase" or "let's too much dirt
through" remarks, but I can say with a fact that the filter oil does get on the
MAF sensors. About 2 years ago, while I worked at a Pontiac dealership there
was a rash of Check engine lights on, and catalytic converters failures on
trans am's and firebirds.
About a month later GM released a service bulletin stating that we were not
to warranty any converters from cars with ken or cotton type filters
installed. It seems the oil was getting on the MAF sensors and distorting the
readings causing the ECM to go full rich and overheating the converters. I now
work for Volvo, and understand they also have had the problem, But not on the
same scale GM has had with there "muscle cars."
Neal
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I run one in everything I own!!! I have a 99 Ford E250 and a 91 CRXSi, all my bikes, and the karts too.... I know you have to make sure they are oiled properly...
Chris R.
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've heard this also. A former internet acquaintence went tot he trouble to study the issue doing before and after oil analysis and found that the oil was indeed dirtier after using the KN. It wasn't whole worlds different if I recall correctly. I would probably be concerned but on my street car (my toy) I rarely get into a dirty environment, and a blown engine would give me an excuse to build a stronger one.
In light of this the question to answer is: would I use them on my daily driver?
No.
You can probably find lots of info on the topic by searching a place called
http://www.bobistheoilguy.com
JV
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Hmmm, interesting to read. At this point in time I SWEAR by K&N filters on our cars and won't use anything else, despite the cost. Since we are 2-strokes I don't think we will have similar problems but more dirt is always bad obviously. Too much filter oil is not a problem for a 2-stroke, but if it does let by more dirt, which I doubt, then it is a problem. All I know is that I pull our filters and clean and re-oil them every weekend. I figure that should cover all problems.
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K&N Sucks.
http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
I have also seen another similar test that produced similar poor results for K&N, but I can't find the link right now. K&N is a triumph of marketing over fact
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Ot here in ths mining state of AZ, studies have been done on dirt
contamination of stationary as well a vehicle motors and olied K&N's
do terribly.
Chuck
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OK, now that we know that K&N filters are not great. A serious question is
what is better?
Thanks ... Jay Novak
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One BMW tuner that did actual testing found one of the performance foam filter to perform very well, itg I believe:
http://www.itgairfilters.com/
Of course, it depends on how long you expect your engine to last. From popular opinion, I'd expect K&N would be perfectly acceptable on an AMW :)
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Better?
A very large area paper filter that filters smaller particle sizes for
one. :->
Less or comparable restriction and better filtering.
Probably quieter too.
I never run K&N's on street cars anymore. Interestingly, there are
also big differences among paper filters. I've seen some paper
replacement filters that that just had a fraction of the number of
pleats that the factory filter had.
Chuck
-------------------
Some filter media is better than others. I work at a company that builds
over the road refrigeration units. We have done some study on different
filters. While I can believe that some fine particles will get through the
K&N's, some will also get through paper filters. Turns out that the old oil
bath filter works the best in dusty and wet conditions. But nobody wants to
use oil-bath anymore. (to old fashion) On some of our units that mount under
the truck body, (close to the wheel spray) we still use the oil-bath but we
are in the process of changing them out for a cyclonic paper filter. The
paper filter has more air pressure drop across it than the oil-bath so we
will lose a little HP, but we are putting in a bigger engine so it should
come out it the wash - so to speak. We are not sure how the paper filter
will hold up in the wet conditions. Time will tell.
So I guess if you want to race, use a race filter. If you want to drive on
the highway, use the filter that came with your vehicle.
Richard
P.S. A few years ago (well maybe many years ago) I was at a pro-bike race
and was looking at some of the two-stroke bikes. I noticed one that had the
carbs facing forward right behind the front wheel and he had no screen or
filters. I ask him if he has trouble with small stones picked up by the
front wheel. He said that was not a problem as the just go right through the
engine and get spit out the exhaust.
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Subject: RE: [F500] Negative Observations on K&N Filters from Saabnet
We have tested New K&N filters that were used on a motorcycle in our labs a few years ago for performance. We tested a new paper filter as well as a new K&N. In short, the K&N was better than paper filter only at the upper end of the range of CFM. We assessed that the higher pressure drop of the paper filter was due to the plys of paper collapsing together at higher CFM demands. That being said, The K&N performance was (as I recall) 6to 8% better than paper. They clamed that it would give 10 to 15 % gain. We contacted K&N on how they came up with there results and said we would like to compare test data..they didnt have anyone that could talk to us. We re-tested the K&N later that year under the same conditions as it came off the bike, aprox. 3000 miles and found it preformed 2% worse than the new paper filter. After cleaning the filter in gas (yes I know the manufacturer says not to do this) the filter was allowed to dry and re tested. It came out at about equal to !
the paper filter. The pressure drop was mostly linier through the CFM range. We didnt test what effect oil would have on the filters ability to allow air to flow. From similar experience the oil will slightly decrease airflow but will trap more dirt.
In a nutshell, for racing, I can see where K&N filters can be of help. For every day driving in your own car, I will be staying with the replicable paper filters.
I calculated the HP value that is required for a 500 CC motor to ingest air at 7500 CFM. I came up with aprox. 0.32 HP. Adding a clean air filter increased power consumption to .38 HP.
Chris
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Interesting Chris!
I think that the reason so many of us use K&N is that they are
compact.
Gasoline cleaning is the way the local 2-stroke pipe and
engine builder cleans all filters. And he is as anal and detail
oriented as they get. A real enginer's engineer.
NOW I wonder if putting a big non-honkin paper filter (or a pair of
them) on a 2-stroke would quiet the intake down some more also.
Chuck
, Sat, 11 Feb 2006 20:25:02 <-- Viewing This Message
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