Shouldn't makle any difference. K&N's don't filter as well as paper elements. Really no reason to use them

 

Do You Sell Paper Filters for a Living?

Shouldn't makle [sic] any difference. K&N's don't filter as well as paper elements. Really no reason to use them

:N_poke:

I have used K&N filters for well over thirty years. For both cars, and motorcycles of mine, family and friends, SCCA racing, they have worked as advertised.

Better filtration, lower restriction, better performance and (usually) better gas mileage. :bananapartyhat:

The one caveat I have is that some n/a engines don't like lowered intake restriction without a corresponding decrease in exhaust back pressure to keep the engine's breathing balanced.

 

You made two changes about the same time so it will be difficult to determine which is the culprit. You will have various folks try to convince you your K&N (or any aftermarket filter) is garbage. I have multiple Blackstone used oil analysis (including my latest last month at 76,000 miles) to indicate it filters as well as or better than the factory filter-but THAT is another thread. :icon_wink:
When you said you went with larger wheels-how were they larger? More weight per wheel? Larger diameter wheels? Wider width? Any of these can affect your gas mileage.

 

Sorry I should have specified, new wheels are 18x8 with a 9.5 wide tire. They had been on for around 3 weeks prior to the air filter change however. I just swapped it out for the stock one during my lunch break to see if it goes back up to what I was averaging. Thanks for the relies, just wanted to check to see if there was some known effect I wasn't aware of.

 

How many miles/ tanks are you comparing consumption over? Any more A/C used?

And if it doesn't come back up after putting the OE filter back in there's always a chance the K&N has trashed your expensive airflow meter...

 

In theory it could -- if you are letting more air in, ECU could see it and add fuel to compensate.

Stan

 

Just hit 1600 miles. The add fuel for the extra airflow makes sense, hopefully it adjusts back to how it was with the stock filter back in. Thanks for the replies guys, I will update in a few days.

 

K&N's can be over-oiled and coat the MAF sensor wire, messing up fuel metering. This rarely happens when new from the factory, but it's easy to over-oil them when you clean or prep them. Cure for this is blowing some carb cleaner right onto the wire, assuming you can see it! Obviously you shouldn't physically touch it.

I would also guess it might be possible that the increased air flow is confusing the CPU, which I believe uses a pressure sensor before the throttle body, as well as after. My understanding of this engine is that it will be very sensitive to airflow and fuel changes, as with a 10.5 Compression Ratio and 17 pounds of boost it is really pushing the envelope of detonation.

If you could access the OBD port with a tester you might be able to see some data about fuel trims.

Looking forward to hearing the results of your experiment.

 

I think you'll find after you drive some more miles your economy will "settle" out. I installed my K&N at about 10K on my '09 XT (as soon as K&N had come out with a part number) and still averaged the same as it did prior to the swap.
One not of caution is that if you have not owned a K&N before, when you get ready to service it, clean it properly, allow it to dry completely, and then add the oil in several light layers so that you do not over coat with the filter oil. I have seen instances where the filter was soaked and should not have been used. :shake:
I also think you'll find that switching from the stock wheels/tires to ones that are probably heavier and at least 2.5 inches wider is going to play a significant part in this mystery.

 

Not wanting to be argued with, reprimanded by management, nor banned from SF.org, I'll refrain from posting my opinions on K&N "filters" and those who use them... in street driven daily drivers.

:shake: uke: :crazy:

 

LOL
Its funny how we all can get along unless brands of oil and brands of air or oil filters are mentions-then it's "Katy bar the door!" :mob::chair: :starwars: :crazy:
Let us know if your mileage changes back up after a few more miles.
-tom

 

LOL
Its funny how we all can get along unless brands of oil and brands of air or oil filters are mentions-then it's "Katy bar the door!" :mob::chair: :starwars: :crazy:

Yea its like Zaino of car detailing forums.

 

^ Keep in mind that I did not mention any air filter tests by "Bob", but linked a specific uoa showing elevated dirt ingestion over several uoa's. True, tdi-rick didn't provide any data but I didn't comment on that either.

If that person's uoa's start trending downward in Si in the same driving conditions (and on the same oil) after ditching the K&N, I think it's a safe bet that it's due to the K&N. That's just the latest example but you will find many other WRX uoa's there with elevated Si running a K&N (maybe more so with a CAI than a panel filter?).

I'm not saying that everyone will have high silicon running a K&N. I have a K&N panel filter sitting in my garage that was used in my wife's Outback that had very low levels of Si in uoa's. I think those cases are fewer though which is why I would recommend a K&N user to do their own uoa.

And I don't buy the argument that it's better for the environment. How do you clean a K&N and what do you do with the oily water?

-Dennis


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K&N, Cracks, and the Environment

^Glad to see we can have a civil discussion. This is drifting off topic so I apologize to our OP.

^ Keep in mind that I did not mention any air filter tests by "Bob", but linked a specific uoa showing elevated dirt ingestion over several uoa's. True, tdi-rick didn't provide any data but I didn't comment on that either.

Fair enough. My post was intended to encompass the previous comments by ADC as well as yours. Sorry I wasn't clear.

If that person's uoa's start trending downward in Si in the same driving conditions (and on the same oil) after ditching the K&N, I think it's a safe bet that it's due to the K&N. That's just the latest example but you will find many other WRX uoa's there with elevated Si running a K&N (maybe more so with a CAI than a panel filter?).

I agree with you except to remind that there are other potential sources of Si in engines; primarily coolants but also leak sealers and other products. Particularly in older or highly stressed engines micro-cracks and gasket defects can come and go. The Silicates usually seal these as they are intended to do, but perhaps not before some tiny amount of Si gets into the oil.

However, since it is difficult to separate these causes and effects it is better to take the careful approach. I would be especially careful if I still lived in the interior of Alaska where there is a great deal of extremely fine Si02 in the form of glacial dust blowing in the air and probably wouldn't run a K&N up there.

And I don't buy the argument that it's better for the environment. How do you clean a K&N and what do you do with the oily water?

-Dennis

That is an excellent question One that sent me scurrying to K&N's web site to read their MSDS. I confess- I wondered about that every time I washed a K&N but was too lazy to find out until you challenged me. Here is what I found:

The filter oil appears to be paraffin based mineral oil with trace amounts of coloring and preservatives (wouldn't want it to go rancid because then it would taste bad on our kitchen cutting boards I guess).

The Power Kleen appears to be an activated form of sodium silicate. (there's that silicon again- who knew:huh

My bet is the sodium silicate binds awfully tight to the mineral oil and to much of the gunk which was trapped by the filter, forming rather large and relatively inert molecules. The resulting sludge should present very little loading effect to my community's sewage treatment plant. They flocculate and filter everything and it eventually ends up in a landfill. In fact, if I use more Power Kleen than necessary it just means, on that day the town needs to add a tiny bit less of their own particular formula of flocculent (some use sodium silicates)- not that they could ever tell the difference.

So which do you feel is worse in the landfill?
A tablespoon of relatively inert oily sludge once a year?
A paper filter complete with sludge?
The fry pan of bacon grease my wife washes straight down the drain most Saturday mornings? :icon_razz:

Thanks for making me think about this! It only hurt a little :catfight:

 

IMO, this is all on topic since it has to do with considerations in running a K&N. And I would prefer it if your wife dumped the bacon grease in the trash so I don't have to swim, surf, and fish in it! :icon_razz:

So it sounds like we agree that cleaning a K&N is similar to dumping some Castrol GTX down the drain.

This product is classified as a HAZARDOUS SUBSTANCE and as DANGEROUS GOODS according to the classification criteria of NOHSC:1088 (2004) and ADG Code (Australia). Extremely flammable aerosol. Vapor Harmful. Excessive inhalation of vapors may cause dizziness, nausea, and headache, loss of consciousness or even death if exposure is prolonged. May be harmful or fatal if swallowed. Repeated exposure may present additional hazards.

DISTILLATES (PETROLEUM), HYDROTREATED HEAVY PARAFFINIC
DECENE, HOMOPOLYMER, HYDROGENATED
C.I. SOLVENT RED 164 (DYE)
PETROLEUM GASES, LIQUIFIED SWEETENED (great for frying bacon!)

http://www.knfilters.com/msds/99-0504.pdf

K&N should go green with their oil and team up with Renewable Lubricants Inc.
http://renewablelube.com/

-Dennis


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How About Using Bacon Grease on my K&N?

IMO, this is all on topic since it has to do with considerations in running a K&N. And I would prefer it if your wife dumped the bacon grease in the trash so I don't have to swim, surf, and fish in it! :icon_razz:

Hi Dennis. LOL:icon_razz: You can relax, I was only trying to make an analogy. Sorry if you missed it.:icon_surprised: We hardly ever eat bacon these days and when we do it is precooked strips that we nuke. The only place bacon fat goes is in us, and not much of that.:icon_frown:

The point I was trying to make is, I am connected to a modern municipal sewer system so it all ends up in the landfill; K&N recharge residue, paper filters and most non-aqueous household waste even if it is liquid when disposed of.

So it sounds like we agree that cleaning a K&N is similar to dumping some Castrol GTX down the drain.

No we don't:icon_eek: Not at all:N_poke: That would be like dumping the filter oil directly down the drain without ever putting it on the filter and then using their cleaner to remove it. You did read what I wrote about the way sodium silicate treats the waste right? Wait. You did, didn't you?

This product is classified as a HAZARDOUS SUBSTANCE and as DANGEROUS GOODS according to the classification criteria of NOHSC:1088 (2004) and ADG Code (Australia). Extremely flammable aerosol. Vapor Harmful. Excessive inhalation of vapors may cause dizziness, nausea, and headache, loss of consciousness or even death if exposure is prolonged. May be harmful or fatal if swallowed. Repeated exposure may present additional hazards.

DISTILLATES (PETROLEUM), HYDROTREATED HEAVY PARAFFINIC
DECENE, HOMOPOLYMER, HYDROGENATED
C.I. SOLVENT RED 164 (DYE)
PETROLEUM GASES, LIQUIFIED SWEETENED (great for frying bacon!)

http://www.knfilters.com/msds/99-0504.pdf

And pure water consumed in sufficient quantity kills. I call BS!:mob: In a red herring argument you conveniently picked the MSDS for filter oil in a pressurized aerosol can.:shrug: Petroleum gas is the propellent to force it out of the can. Olive oil in a pressurized can with flammable gas propellent would have a similar MSDS- like some non-stick cooking sprays used to be.

I haven't seen that aerosol K&N product offered for sale in well over ten years. I don't know if they still make it and wish they hadn't ever:icon_frown:

I only use hand pumps to spray both K&N and olive oil. (no, not the same pump, give me a break):shake:

K&N should go green with their oil and team up with Renewable Lubricants Inc.
Renewable Lubricants Inc

-Dennis

Now there is something we agree on! Why don't you contact K&N and suggest it directly to them.:bananapowerslide: The overall effect may not be too great though, since it only takes about a tablespoon a year at most.

However, you chose to ignore other important environmental trade offs of the opposing systems:

Energy and carbon: The oil is negligible but both systems use filtration media and a plastic containment designed to hold the media and create a seal with the engine. To me, the plastic looks very similar in both systems so maybe the main energy/materials differences are in the media; maybe a factor of 1-1/2 to one? Only the manufacturers know for sure and the are not telling. If my estimate is even close, I have cut the carbon and energy footprint for this purpose by a factor of about 13:1 or >92% compared to disposable paper.

Solid Waste: 20:1 reduction in solid waste in my real world example.

These latter two will only get better because I am giving my Civic to a trusted mechanic who has agreed to perform required and deferred maintenance on the engine, replace the rear main seal, and repair the body before selling it. His guess is the K&N filter might continue to offset paper for another 3-5 years.:Banane35:

 

K&N are ok to use on most US street. Our environment are not that harsh with very little dust. I would not use K&N if I live where dust is a problem.

Honda engine are just build a lot better. They might have less torque but the tolerance, material harness and quality control are just a lot better than Subaru Engine. Subaru are not that consistent and are a lot more prone to spun bearing. You cannot base prior experience with Honda engine with K&N reliability to Subaru engine with K&N. Subaru with turbo makes a lot of power but so does Honda engine with turbo.

I think K&N recommend resetting the ECU to maximize the benefit or higher flow. Your ECU might be adding fuel because its still using learned MAF value from the old filter.

 

Reset the

jc2

 

The ECU should reprogram itself in response to increased air flow, unless the adjustment is beyond its possible range of fuel trims, which is unlikely.

 

Any updates on the K&N Mpg???