K&N Air Filters

[EWAustin]

Hey Guys,
My Dad sent me this from the Saabnet, which is linked from RoadFly's Porsche section, so maybe some of you have seen this before.

The thesis of the article is that K&N filters let through more fine particles resulting in greater wear and tear on the engines. It is backed up by leakdown numbers from a racing mechanic. Also it mentions how the oil can cause problems when it gets onto air-metering devices (MAFs etc). I was just wondering if anybody had seen this type of results before. Especially since I was thinking about putting one on my car (maybe AMSOIL would be better?)


I worked for race teams for years. One Toyota Atlantic teem I worked on the driver thought the car was losing power from the start of a race to the end. So we did leak down checks when we got new engines in. 3% leak down- New. At the end of a race we checked it again and we got 29% leak down. So we sent the head to get the valves done and checked the leak down when the head returned. 4%- Leak down. At the end of the next race 31%- leak down. So we put three dabs of grease down streem of the air filter. "K&N" The next engine came in with 3%-leak down new. And at the end of the race 32%- leak down and the dabs of greas were full of grit. So we changed the filter to a oiled fome filter. 3%- leak down new and at the end of the next race? 18%-leak down. Better still not good. So we made a new air box and used a Mustang GT stock air filter. 3%-leak down new at the end of the next race? 1%- leak down yes I said "1%". The rings bed in and the engine seals up. We went from changing a engine at 300 miles with 29 to 34% leak down to. Changing the engine at 800 miles with 7% leak down.

So the bottom line is. You mite gain a littel more power (1 to 2hp) but it will not last long and befor you know it you will have a LOT less.
I work on 944s only and when I tare down a 944 engine that has had a K&N filter the cyclenders have a LOT of scores from dirt that got through the filter.
If you dont beleve me do the grease test your self. Take out the filter and put a dab of grease in the air box. Then put your K&N filter in and dive the car for a few weeks and pull the filter out and check the dab of grease.

Good Luck Mike F



Here is the original post on RoadFly (http://forums1.roadfly.com/porsche/forums/924-944-968/forum.php?postid=4959457&page=1)

[Ivan]

Had a problem with them on both the WRX and the Evo. Might have been over-oiling them, but both resulted in "shmutz" covered MAF sensors... seriously degraded performance. No real dust or particulate buildup in the air boxes, but I wouldn't doubt that there's more crap getting into the engine.

It's high quality dry filters for me from now on.

[SmokingTires]

It has been long discussed. More air flow will always mean less dirt protection. You have to give up some protection to gain hp. That's why race cars often run filterless. They just have to rebuild their engines yearly.

If you don't over oil the filter, you shouldn't have problems with the air flow meter. Your going to get more dirt in the engine, that's for sure. It all depends on your dedication. If you want to do everything to get yourself closer to winning, you'll use the filter. If your more worried about your cars life, you won't.


I just have doubts that it will kill your engine horribly fast. Maybe hack 10k miles off it's life, but it won't dye by the end of the year just from using one.

[SaturnRaycer]

The guy writing the piece about leakdown using K&N filters lives in a different world than the rest of us. What makes his world different from ours is how his engines are used.

Because of the time demands of racing, and the nature of the engines, they are assembled, run long enough to verify that they are working right, and put in a race car. They live a very short and strenuous life.

In addition, the writer didn't elaborate on the ambient conditions. Engines built and tested in a desert environment may suffer more than if they were built and tested in a more humid climate because there is more very fine dust in the air due to low humidity.

Tolerances on racing engines are much tighter than high performance street engines. These tight tolerances mean that more power can be extracted, but at the cost of greater wear. This partially explains why Nameless Racing can get 600 hp out of their Quasimodo engine, while the street version puts out 250 hp reliably.

K&N understands this quite well. Joe Streetguy wants more power from his Quasimodo GT, so he buys a K&N. It flows better and he's getting another 10 hp (up to 260 - just about 5%) He hasn't significantly compromised reliabliity so K&N can confidently give a Million Mile Warranty. There's a better chance that Joe will trash his engine some other way, so it's a reasonable risk.

If Joe is a normal autox-er, he wails on his engine for one to two minutes at a time; not running at or near redline for 90 minutes straight. He spends much more of his engine's life significantly below redline or peak power, so the leakdown issue doesn't show up for tens of thousands of miles, if ever.

Ask yourself, when was the last time you did a leakdown test on your engine? Chances are, the only time was when it seemed "down on power" or you knew you did something that wasn't good or wise. If our livelihood depended on building engines that could put out huge power for up to 1,000 miles, we'd probably do leak-down tests routinely.

Bottom Line - K&N, Fram Air Hogs, or any of the myriad of oiled foam filters flow better than that dry paper filter. We're willing to trade a small amount of engine life for an improvement on the "seat-of-pants dyno".

[Godspeed]

When I get a new car, the first thing I usually do is drop in a K & N. Mostly, for the milage gain. I used one in my Mustang for over 40k miles, sold the car with 94k miles on it. Our Mazda has 91k miles and we've used a K & N in that for the last 50k. No problems with either car.

[stoooo]

Still not a flame.

I am on the verge of buying a K&N cleaning kit for the filter in my 2001 Subaru Impreza 2.5RS. I have no brand loyalty at this point, but the K&N marketing machine is *very* persuasive. If I was to invest my money in one of these super-whizzy Amsoil air filters instead, would it deliver performance on a par with the current K&N ?

I checked out the site, but couldn't find a part number for my car. I found my car in their application list, but the part number they have doesn't mesh with their online shop.

Does considering this make me a progressive thinker ?

Stuart.

[AlexL]

The Amsoil filter is one of the most restrictive filters out there, and look at how quickly it gets loaded up with dirt.

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

[stoooo]

Not yet available for that car.
Only the Wix element.
Sorry.

Any ETA ? Do they want a test mule ? My CAI is just a bendy tube (Ganzflow) to the inner fender that hooks up to the stock airbox. As such, I would be looking for a panel filter, not a cone filter.

Stuart.

[stoooo]

The Amsoil filter is one of the most restrictive filters out there, and look at how quickly it gets loaded up with dirt.

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
That's discouraging.

Stuart.

[PeteySi]

The Amsoil filter is one of the most restrictive filters out there, and look at how quickly it gets loaded up with dirt.

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm


I just read through the results on that study. Its actually very interesting. In RELATIVE flow, the AMS Oil Filter isn't too bad, registering about 2.3 inches at max flow (350 CFM). For comparison, K&N registers 1.3 and Factory AC registers 3.2.

Where the AMS is notably inferior is in its ability to collect dust. Its performance goes down significantly as it gets dirtier. Simple solution: clean it more often.

[esper]

Any ETA ? Do they want a test mule ? My CAI is just a bendy tube (Ganzflow) to the inner fender that hooks up to the stock airbox. As such, I would be looking for a panel filter, not a cone filter.

Stuart.

I had a ganzflow with a k&n and I never had an problems from it.

I also used double sided tape on the engine side of the airbox and it was never any dirtier than it was with the paper filter. I just had to be careful to take my time cleaning it to make sure it was throuoghly oiled but not over oiled.

[stoooo]

year, make and model.
Check back in post #8. 2001 Subaru Impreza 2.5RS. And, in case it matters, it's a white four door.

Bye for now,
Stuart.

[stoooo]

I had a ganzflow with a k&n and I never had an problems from it.
I'm not having problems either, but I suspect the filter is in need of a good clean. If I have to buy the cleaning kit for it, that money might be better spent on a fresh filter that I can just vacuum clean, *if* that new filter will work as well as the current K&N one.

Our MAP based Imprezas don't even have to worry about getting oil all over the MAF wire, 'cos we don't have one :)

Stuart.

[stoooo]

one of these. We'll have to see how his does..........
So, my other question stands; any ETA on a product for my car ? Should I contact Amsoil myself and give them a nudge ?

Stuart.

[stoooo]

That's what gets the ball rolling, demand!
Know anyone in particular I should contact ? Or should I just hit up their info@ email address ?

Stuart.

[stoooo]

Apparently, input isn't really what they're seeking after all...

"Thank you for contacting AMSOIL with your concerns.

In response to your inquiry, all further EaA filters are going to be released due to customer demand. The next wave of EaA filters will more than likely be available in mid summer. I can tell you that an EaA filter for the Impreza is not likely at this time.

Thank you again for the opportunity to respond to your concerns. As always, please feel free to contact us again if we can be of further assistance.

Sincerely,
Bryan Kershaw
AMSOIL Technical Service"

So, I'll be shopping for a K&N cleaning kit then.

Stuart.

[91TB78]

I'm currently using the EaA filter in my 05 STi. It works fine for me. I'll check it in a couple days to see how it's doing, but most filters are fine for stock application. I've thought about going with a cold air intake with K&N cone filter...but I just can't pull the trigger at this point.

[stoooo]

The STi and '01 RS filters are *very* different. I need a panel filter to sit in the stock airbox. My CAI is a very basic tube with a couple of bends in it that goes directly from the fender to the airbox. Where my airbox sits, you've got an intercooler.

I was mainly interested in this because I'm lazy, and don't want to have to clean and re-oil the K&N. Also, Amsoil are practically a local firm, and it gives me warm fuzzies to support local businesses. But if they won't provide a product for me to buy, I'll just go to their competitors instead.

Bye for now,
Stuart.