REAL air filter testing. More proof that K&N is junk.

I once found a site in Japanese where some creative street racers decided to test filters. They used a shop vac, a measured spoonful of copier toner, and what appeared to be coffee filters. As usual the K&N was near the bottom in filtering ability.

They were also quite worried about MAP sensor failures on oiled air filter equipped cars. Both K&N gauze type and oiled foam.

Its more extreme with a Diesel, as in the SPICER test above, but any reduction in restriction (K&N's claim to fame) is compensated by closing the throttle. Your engine requires one quantity of air per unit of work and this quantity is regulated by the sum of the throttle plate, air filter restriction, and other intake restrictions. Reduce restriction on one and increase it on another to maintain the same quantity of air. So unless your foot is pressed against the floorboard the air filter restriction doesn't matter.

With the HP race automakers want every cheap horse they can find. If air filters were as important for HP as K&N suggests then all an automaker has to do is increase the size of their paper air filters. Bigger paper filters flow the same volume with less restriction. Only example I know of is the huge Porsche 928 air filter.

You are right the benefit of K/N is questionable. If it is that good, why doesn't car manufacturer install them in their car? As far as increase horsepower! all people have to do is to remove the air filter and try it out to see if they can tell an improvement. Replace the filter after the test run. My brother has purchased after market K/N cold air intake. We have tested the car with and without using G-Tech (accelerometer to test for acceleration). Test after tests, weather condition, road condition. There is no benefit. We did not test its filtration ability but sound the copier toner is a logical way to test.

WOW.

Once it got to a throw-away paper filter, I figured it would all be the same. I think I should look into finding an AC Delco that meets the size I've decided on for my beast!!

GMC Gremlin

I wont defend K&N officially however, the comment that you dont need that extra air and wont benefit from it is ludicrous. More air, and cooler air, to a point will get you more power, maybe not enough to really notice.. 5-6 hp is probably about average. Why doesnt the dealer put it on, because it gives a bit more growl with that extra flow. add a CAI set up and you really increase noise. It all depends on the vehicle. My Discovery runs just fine with the factory filter and being that dirt is the issue on an offroad vehicle I would prefer to be safe rather than sorry. However, a conical filter (not K&N) on a high flow CAI set up produces noticible increase in high end power on every BMW I have put them on, plus the roar you get with the CAI/foam filter is awesome.

This is a very interesting study. It displays the AC Delco filter in almost the same light as others try to display the K&N filter.

Are there other studies out there like this? It is difficult to analyze one versus another. But if there were three different, unrelated surveys and they all pointed the same way . . .

Thinking twice about putting a K&N on my new vehicle. Maybe it belongs on eBay instead?

I guess if the price is reasonable and you're not concern about if you actually gain 5 to 6 hp than install one. But paying over 100 dollars is bit too much for me. I wont say that I know a lot about engine breathing nor know how to tune the engine to get extra horsepower with just 100 or 200 dollars. I thought that to get extra horse power you need air + fuel then exhaust the burnt fuel out with less exhaust back pressure. So if that case, than improving air does not necessary improve overall engine performance. Ofcourse I am not talking about clog paper air filter either. We have to assume that the stock air filter is clean and is representable for this test. So change once per year is all you need for average driving condition. As far as CAI, once again not being the expert on this and since we are in discussion mode, most CAI I have seen is placed inside engine bay. There is no fresh air inlet from outside such as ramp-air to funnel the cold air in, do you still think there is a cold air benefit? Cold air is better for engine without question as it is more dense than warm air. I can see that if you change your air intake ports or opening your throttle body or MAF sensor to increase the cross sectional area plus air inlet from outside to get cooler air, then you will see a benefit. I have a Bonneville SSEi. I have removed the air filter, remove the MAF screen one day on open road to test the car. With the accelerometer, I took several readings and the results does not indicate with or without air filter to simulate an ideal filter (stock air box) that there is an improvement. We did the same test on Focus with Zetech engine but this time with full CAI cone kit couple with 2 inches aluminum pipe. Once again, the results is not conclusive. Perhaps my accelerometer measurement resolution and accuracy is questionable, but still the benefit between stock air filter vs CAI with K/N or what have you is still out there. Having said that, improve Hp does not come cheap with just K/N. I think there is more to it than that.

"Corey Shuman" wrote in message news: snipped-for-privacy@f14g2000cwb.googlegroups.com...

There are two ways to know for sure and only two ways. One take the beast to a shop with a dyno and put it on it, or two go to the drag strip and make a dozen runs with each set up and see what the average times are. Races are won and lost by margins less than a tenth of a second. 5-6 hp can be that difference. On partial throttle, your not going to see a major difference. Its when your toes are tickling the throttle plates the increased air flow comes into play. Whitelightning

Air + Fuel + Efficiency.

All other things being equil if you make the motor more efficient at burning gas and turning it into power you get more power. It takes work to creat the vacume that draws air in. Less intake restriction means more of the motors power can go to HP. That's why K&N and any other means of less restrictive air flow (and exaust from the push it out standpoint) increases HP and MPG. Double stacking a standard filter should do the same thing. I have to wonder why more people don't do that, or sell a kit...

As for why car makers don't do it, everthing they do is a balance between making what it takes to sell a car and making money on the cars they sell. You won't see a lot of tricks on stock cars because of that.

...

The K&N was the best at what it claimed to be the best at. Free air flow. One thing the study didn't talk about what how much tolernace for dirt did the motor have? Were all air filters within the manufactures specs?

Less junk getting into your motor is a good thnig, but at some point it won't matter due to your oil filter etc.

Check this link below to read other testimonials about K/N and its benefits/not so good. I thought it is interesting...

representable

difference.

I hate to break it to you Corey but: Those BMWs only SOUNDED faster..... :)

WHAT??!! K/N filters aren't worth the money??!! You mean their literature is full of lies??!! What's this world coming to?

All kidding aside, I've never purchased a K/N filter for the simple reason that, more airflow through a similar sized filter equals more dirt. It's elementary.

I learned my lesson about creative marketing when I had a Aero Turbo muffler installed on my truck. Their literature boasted large increases in MPG with their muffler. I figured any increase would be worth it. I didn't realize any increase at all.

NES

That is why they call that stuff "after market." If ANY of the stuff actually did what they claimed it would not be "after market," because every automotive manufacture would be using the stuff. Every manufacture is looking for every advantage over the other to meet or exceed CAFE

mike hunt

NES wrote:

What are the particulars concerning your Aero Turbo installation. I know the literature makes claims that defy the physical rules of the universe, but I keep hearing stories that seem to support their claims. What year and model vehicle did you put it on, did you follow their requirements? And what was the actual outcome?? Thanks,

George

Wrong.

Lets say you are cruising at 80 MPH in your gasoline land ark at 3,000 RPM. Note your throttle position with stock paper air filter. Now replace the filter with your choice of super non-restrictive filter and note your throttle position under the same conditions. It is closed more than previously because any and all restriction "saved" by the "performance" air filter is compensated for at the throttle body.

Don't bother to actually try the above as you would have to be able to measure the throttle position *very* accurately (the difference between stock filter and no filter isn't much.) And then average the results because under these conditions everything is always changing.

Under the stated conditions HP output remains constant. RPM remains constant. The quantity of air does not change. The engine will suck air on the intake exactly as hard with either filter. Look beyond the air filter, the only point "restriction" matters is that which is seen at the intake valves. K&N is happy if you only consider the restriction between the throttle and outside atmosphere.

The only thing which is important is the *sum* of the intake restriction. For a given HP output on a gasoline engine that sum will remain constant because it is the very thing which regulates HP output.

If the engine gets more air the fuel system will add more fuel to maintain combustion and emissions. More fuel = more HP = more faster, where the driver compensates by lifting on the throttle to reduce the air and therefore HP. The only time "less restriction" buys you anything is under full throttle.

The link which started this thread was specifically interested in air filter performance as related to Diesel engines. The intake equation is different as the Diesel does not have a throttle. More air could result in more efficiency.

Diesel doesn't have a throttle, now that's the damnedest thing I ever heard. Whitelightning

wrote in message news: snipped-for-privacy@mailcity.com...

Most "after market" stuff does work. But then most after market is geared at power and performance, which does not go hand and hand with CAFE, but usually against it. The after market has been providing roller lifters and rocker arms since the early 70's. why? Because they reduce friction in the valve train, which frees up horse power, and allows higher rpms. Guess what many auto manufactures are using these days? Do you think Chevy would have put V-8s in the Monza if there hadn't been so many people using after market to put them in Vegas? Or ford have put V-8s in the Mustang II if so many people hadn't used after market kits to do the same with Pintos and Mustang II's? Hot Rodders where rigging up snorkels with dryer hose and then after market kits to get cool air from out side the engine bay into the intake way back in the early 60's. How many manufactures don't have ducting from the radiator horn to the intake these days? We knew back in the early 70's that an air dam across the front made the car handle better, and run faster, that ground affects kits got us better fuel mileage and handling.. How many cars today don't have some sort of air dam and ground affects ether as an added on piece like the S-10s, or incorporated into the bumper design and rocker panels like the Mustang, Monte Carlo, Impala and the Corvette? The after market has been providing performance suspension components for ever. Its only been in the last 10-15 years that you have seen manufactures start using teflon and polyurethane bushings, and performance shocks/struts like Bilstien. It was the automotive enthusiast and the after market that got sway bars on oem. Like any other industy there are snake oil salesmen out there. But they make up a very small percentage of the industry. Of course if you were one of those that was always trying to get a bit more out of what the manufacturer sold you, you would know this. OEM never does anyhting that costs more till they are forced to by consumer demand and lost sales kick them in the gonads and getting their attention.

Whitelightning