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Would you/do you use the K&N cone air filter?

General engine tech -- Drag Racing to Circle Track

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PackardV8
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Would you/do you use the K&N cone air filter?

Post by PackardV8 »

I go to the occasional car show and can always depend on seeing one or more examples of this which makes me crazy. The owner spent many thousands of dollars on a custom built engine and tops it off with this tiny little air filter sitting directly behind the radiator.
Image


Even worse, I was touring one of the top rod shops in the country, where the entry level cars start at $250,000. There was a mid-year Corvette with a "750-horsepower LS" There was a high dollar composite intake with front-mounted throttle bodies. From this, a 4" diameter tube made a 180-degree bend and positioned one of these K&Ns directly over the left exhaust header. I wanted to take a photo, but at the beginning of the tour they said they were prohibited, "Too many people stealing our ideas." They can keep that one.
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Re: Would you/do you use the K&N cone air filter?

Post by BLSTIC »

Because it's compact, flows a lot and has an internal bellmouth.

Why people insist on leaving it in open air is beyond me though
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Re: Would you/do you use the K&N cone air filter?

Post by Protech Racing »

They pass a lot of dust. But make power if the charge is cooled.
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Re: Would you/do you use the K&N cone air filter?

Post by Roundybout »

I usually use paper style filters but my dirt bikes and side by side use a similar style (UNI-Filter brand made of foam) that is meant to be oiled. I know the K&N filters use the oil too but I find there is such a lack of filter media in them they either clog up real quick or don’t filter sufficiently. They seem to be really finicky on either too much oil or not enough.
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Re: Would you/do you use the K&N cone air filter?

Post by jake197000 »

I use a big ass one mounted in my right front inner fender with a 3 inch pipe going to my throttle body on my supercharged 331sbf.no problems ever.had the car 30 years now.only problem I have is traction,but you can steer it with the throttle.this car is so fun.red 87 mustang convertible.original paint.pound the snot out of it.never breaks.cnc ported twisted wedge heads Anderson stage 2 blower cam etc,etc.
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Re: Would you/do you use the K&N cone air filter?

Post by MadBill »

PackardV8 wrote: Tue Dec 31, 2019 5:25 pm I go to the occasional car show and can always depend on seeing one or more examples of this which makes me crazy. The owner spent many thousands of dollars on a custom built engine and tops it off with this tiny little air filter sitting directly behind the radiator.
Image...
Here's some info from an earlier thread:

\Re: Air filter requirements for 462 bbc
Post by MadBill » Thu Jan 14, 2016 9:45 pm

Per K&N:

A=(CID X RPM) / 20,839
A = effective filtering area


CID = cubic inch displacement
RPM = revolutions per minute
at maximum power
Example: A 350 CID Chevy engine with a horsepower peak at 5,500 rpm.
A=(350 X 5500) / 20,839 = 92.4 square inches
If you are sizing a panel filter, multiply the width of the filter area (not the rubber seal) times its length. If you are sizing a round filter, use the following formula to determine the height of the filter.

H=(A / D * 3.14)+0.75
A = effective filtering area


H = height
D = outside diameter of the filter
3.14 = pi
0.75 = the rubber end caps
Example:
H=(92.4 / 12 * 3.14)+0.75 = 3.20 inches

And here's a spreadsheet for the surface area of a truncated cone: http://www.onlineconversion.com/object_ ... c_cone.htm
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Re: Would you/do you use the K&N cone air filter?

Post by Krooser »

They make a lot of noise and noise equals HP...
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Re: Would you/do you use the K&N cone air filter?

Post by tjus »

i dont use oiled ones but i use aem dryflow filters. they work great in dusty,muddy,wet conditions and are easy to clean
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Re: Would you/do you use the K&N cone air filter?

Post by mag2555 »

Do a search for Hot Rod tv air filter test they did a few years ago and enjoy the ride!
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Re: Would you/do you use the K&N cone air filter?

Post by Truckedup »

I had my vintage race bike on the chassis dyno and tried some air filters....The bike is a twin cylinder 4 stroke OHV, 40 cubic inches total, 57 RWHP..two K&N's ,3 inch diameter x 5 inch long caused a sight drop in power..However I did not try different jetting..On my vintage Triumph 750 twin street bike making about 50 RWHP, two small dry cone filters 3-1/2 x 3 caused no noticable drop in power and no change in the air/fuel ratio compared to no air filters when I had the meter on the engine..
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Re: Would you/do you use the K&N cone air filter?

Post by Dan Timberlake »

Protech Racing wrote: Tue Dec 31, 2019 7:46 pm They pass a lot of dust. But make power if the charge is cooled.
Fine grit on the oily surface downstream from my K&Ns too. Two stroke dirt bikes.
And an online Usenet (remember those groups?) I respected, named MXTuner, reported consistently similar grit passing results with K&N air filters, so avoided them whenever possible.

I know particles under a certain size are not very harmful in fuel systems ( different µm for carbs and even 2 or 3 types of fuel injection ) and lube systems.
I have not read yet about a benign size of abrasive for rings and cylinder walls.

But if I can see debris in the intake using Filter "X", I'm moving on.

In the 60s and 70s in the "say smokey" column in Pop Science,Smokey often extolled the virtues of good paper air filters. I do not know if he had K&N experience at that point, or was referencing OEM oil bath air filters.

I forget what he said in the "Power Secrets" book about air filters.
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Re: Would you/do you use the K&N cone air filter?

Post by englertracing »

IMAG0114.jpg
Prefer foam
Big ones

Take one look at what a knn will pass. Id never run that shit.
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Re: Would you/do you use the K&N cone air filter?

Post by PackardV8 »

Thanks for all the replies. There are certainly questions.

I guess my revulsion is also as much at where they're being located, drawing air from the hottest part of the engine compartment.
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Re: Would you/do you use the K&N cone air filter?

Post by BBO Omega »

I have heard many horror stories of early cylinder wall wear when K&N Air Filters are utilized. That said, my 2003 Tahoe has 140,000 miles on the 5.3 [with the last 10,000 miles enjoying 12 psi of boost on occasions] and has had a K&N Open Element kit installed for the last 120,000 miles. The engine still runs awesome, and uses no more oil now between changes as it did new [about 1/2 quart between oil changes]. I don't believe that the K&N CAI kit adds any HP as it does suck in plenty of hot air, but is does look and sound much nicer than the stock air box.
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Re: Would you/do you use the K&N cone air filter?

Post by Truckedup »

I bought a well used Yamaha Rhino side by side last year for short money.It has a lot of dirt and weeds stuck to the chassis..It needed a lot of supension repairs but the engine ran well...It had a K&N filter in the stock airbox...The filter was covered in so much dirt I was surprised it ran at all...Downstream from the filter there was zero grit or dirt to be seen or on your finger...
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