My impressions after 47K miles of K&N filtering.

[Patman]

This might sound really silly but I wonder if you'd get less dirt in your oil if you wrapped the K&N filter with some pantihose? I know they sell those filter wraps too, but pantihose might just help out too wouldn't it? Of course you could only do this on a cone type K&N.

I'd feel like a fool going into the ladies section of Walmart to look for pantihose though, and which brand to get? They don't show air flow ratings on the boxes!

And my wife would kill me if I ever raided her pantihose drawer!

I'm dying to get the 10hp boost from the K&N FIPK for my LT1, but don't want the extra dirt getting into my oil either. If only I could replace the K&N cone with a paper cone. The main gain from that unit is the plastic tubing, not the filter itself.

 

[Bio-T]

I used a K+N oval in the factory air box. I used it for apprx. 42K miles and those 2 million holes in the filter, going down the road in formation left an incredible amount of dirt in the intake tube. Oiled and cleaned properly didn't help. I replace it with a huge paper, now many thousand miles later no problems, no dirt and low silicon on my analysis.

http://www.bobistheoilguy.com/images/vettemanfilter.jpg

 

[UncleS2]

I removed my K&N from the factory airbox last weekend when I changed the oil, & installed a new paper filter. The K&N had been used for ~37-38K miles, untouched in that interval. Yes, when held to the light, I could see some tiny holes through it- even through that heavy coat of "filtration dirt"

. BUT: When I wiped out the airbox with clean fingers first, & then with a clean white paper towel, *no* dirt showed up. Someday, I hope to get a good explanation for this. If past experience holds true, when I remove the paper filter in 12-15K, there will be a bit of light, fine dust in the airbox. Oil analysis should tell the tale on dirt.

My take on the K&N's? They're not the miracle product that some think; properly used & serviced, in some cars they're not as bad as others think.

And Patman; for a pre-filter for a cone K&N type filter, instead of pantyhose, get some of those old lady, size semi-jumbo, industrial strength knee-high stockings.

[ October 13, 2003, 12:25 AM: Message edited by: Stuart Hughes ]

 

[mf150]

quote:

---

Originally posted by AnthonyS:
Flow and filtering ability are inversely proportional. This is my hypothesis, and no testing I have ever seen refutes it, so I have to assume it is still true. If one goes up, the other must go down.

The only way to increase flow and maitain filtration ability is to increase the size of the filter. If you increase the ability of a fixed size filter to flow better, it will filter less.

Any filter will filter better as it becomes dirty until it reaches saturation. Claiming it as part of your advertising scheme is rather silly. This is true of any filter.... of course as a filter becomes more saturated its flow ability will go down.

You'll notice each and everyone of my hypothesis (two stated above) follow common sense and do not violate any physical laws. The sad reality is that magic air filters do not exist.

A high flow filter may filter adequately enough for you, and it may not. That is the ultimate decision you are left with. I'm not making decisions for anyone, but I flat refuse to believe in the magical filter advertising available.

---

the first paragraph is counter scientific method. In science we do not assume anything until we have empirical data to show that there is a correlation or cause.

you do have a good point about surface area and increased flow.

 

[Rob T]

Just some input,

I have used K&N filters on my last three cars. 96 Monte Carlo Z34, 50,000 miles w/ K&N, no dirt in intake tube,
2001 S10 ZR2, 30,000 miles w/ K&N, no dirt in intake tube,
2003 Silverado 2500HD Duramax 11,000 miles and still going w/ K&N, no dirt in intake tube, and I believe a diesel pulls in a lot more air,

All of my filters have fit well and tight.

IMHO, the only way the oil will get on the inside of the intake tube is if it was over oiled, because if the oil doesn't get on the inside with my diesel it will never get on the inside of a gas engine.

 

[2KBMW]

I installed a K&N filter in my 2000 328i BMW
4 months ago. I checked it this morning and
everything past the filter (upper filter box
and tube leading to the engine) were spotless.
The inlet snorkel and bottem section of the
filter box housing had a light coating of dust
which is understandable. My filter fit snug
and perfect. Make sure filter is the proper
one for you car or truck. I called around then
and got two different part numbers. Some places
were using older K&N parts catalogs. The difference between the two filters was the rubber
gasket mine came with which is important for a
perfect fit.

 

[AnthonyS]

quote:

---

Originally posted by mf150:

quote:

---

Originally posted by AnthonyS:
Flow and filtering ability are inversely proportional. This is my hypothesis, and no testing I have ever seen refutes it, so I have to assume it is still true. If one goes up, the other must go down.

The only way to increase flow and maitain filtration ability is to increase the size of the filter. If you increase the ability of a fixed size filter to flow better, it will filter less.

Any filter will filter better as it becomes dirty until it reaches saturation. Claiming it as part of your advertising scheme is rather silly. This is true of any filter.... of course as a filter becomes more saturated its flow ability will go down.

You'll notice each and everyone of my hypothesis (two stated above) follow common sense and do not violate any physical laws. The sad reality is that magic air filters do not exist.

A high flow filter may filter adequately enough for you, and it may not. That is the ultimate decision you are left with. I'm not making decisions for anyone, but I flat refuse to believe in the magical filter advertising available.

---

the first paragraph is counter scientific method. In science we do not assume anything until we have empirical data to show that there is a correlation or cause.

you do have a good point about surface area and increased flow.

---

Its funny that you state the first paragraph is counter to scientific method. Show me one single solitary test that shows flow and filtering ability are notinversely proportional. Just one, and I'll be satisfied. Having studied fluid dynamics a bit and spent years working on all sorts of fluid systems myself, I know it is true from actual observation thousands of time.

Here is a simple test to illustrate what I'm talking about. It also passes the common sense test too. Let's use something to filter our air or fluid. We'll make it a solid sheet of steel, glass or wood. We have a perfect dirt filter, and zero flow. Now lets punch some holes in it. It flows a whole lot better, but filters less. Now lets just remove the "filter" all together. Wow flow is incredible, but nothing is being filtered. Amazing relationship? Crazy hypothesis in violation of "scientific method." I think not. How many of these experiments does one need to see to belive it is "scientific?"

Until someone can provide me one single test that shows my null hypothesis is false, I'll stick to defending it, which is appropriate.

 

[JohnnyO]

I've run a K&N in my 4.0 SOHC Ranger for about a year and a half. Never saw any dirt in the intake tube, though I've cleaned the MAF twice just in case. Throttle response is better but this truck is going to suck gas no matter what I do it seems. I have noticed that the oil gets dirty sooner though. I agree that a smaller engine probably isn't going to flow enough air for it to matter. The 502 big blocks you see in HOT ROD or whatever are a different story.

[ November 21, 2003, 10:40 AM: Message edited by: JohnnyO ]

 

[S2000driver]

A number of years ago I installed a new K&N air filter on a 95 Integra in the spring. During that summer I was detailing under the hood and took off the intake tube. I was surprised to find it was coated inside with gritty red dust. I could see the throttle plate was getting dirty too.

I immediately cleaned everything up and went back to the stock filter. Never bought another oiled aftermarket product after that.

I would only suggest a K&N if you plan to beat the car and sell it before you have problems with engine wear. When you floor it frequently, you can take advantage of the few extra high RPM horsepower.