A K&N filter can't increase the demand for air, engine modifications do that. In my 20+ years of turbo cars, I *know* I've put stock paper filters with >half< the surface area of the 80 filter on engines producing twice the HP of the stock 80. That indicates to me, that you could double the airflow going thru a 80 application K&N and get 0 gain in HP.
SJ
If other engine modifications are made to increase demand for air then why not allow some more in there?
If I am interested in having a few more hp at higher RPMs then not allow me some more air.
The funny thing about looking for more horsepower is each modification you make might only add so much power. But the more mods you employ the more your results will improve. Tweaking a stupid air filter isn't going to do much by itself. But, if you have done 9 other things to tweak overall performance than its just a piece in the overall picture. I know that a K&N doesn't flow that much better than your decent paper filter, but it does flow better in tests (I will post some for you). It may only make your throttle response a little more crisp or add a few horsepower at higher rpms, but it adds a little. If you have 9 other things adding power, you trim a little weight here and there, then your efforts our going to add up.
Below is USA today's car columnist. #1 and #2 are both guys who did independent tests and their results. One thinks the K&N is worth it (he did more than just change the filter) and the other sees a difference in the media but thinks, that alone, its less than dramatic. Fair and balanced.
Eugene, OR: Good day James - I have an 05 Dodge 2500 Hemi. Was wondering if the aftermarket air systems (K&N for example) really make a difference. If so, is it mostly increased HP, or is it better fuel mileage, or both ?? If they are that good - why are they not factory installs? Thanks much for your opinion!
James Healey: Free-flow air filters such as K&N, and the cold-air intake systems can make a difference. But will you notice? Horsepower tends to be gained at higher rpm, and you might not run your 2500 truck in the high-rev range much. Even if you do, an increase of a few %, at best, probably wouldn't be obvious. What such systems do is make throttle response crisper and give the engine a slightly livelier, spunkier feel, which to me is worthwhile. But better mpg? Don't count on it. If anything, it's likely to be worse because you enjoy the new feel of the engine enough that you become friendlier with the gas pedal. All that notwithstanding, I'm a fan of the K&N or similar free-flowing, drop-in air filters. Cheap -- especially because they are reusable almost forever so you don't pay for new air filters -- way to tweak the engine just a bit. If you add a free-flow exhaust, the free-flow air filters really become meaningful.
http://transcripts.usatoday.com/Chats/transcript.aspx?c=519
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#1
No one is paid me to perform this test. I am conducting it out of curiosity, interest, and as a service to all automotive enthusiasts. I want to especially thank my wife for putting up with me, Scott H. (K&N), Chris O. (Baldwin) Kevin B. (Amsoil & Jackson Racing), and Cliff K. (Mazda filter) for donating air filters. I bought the Napa filter, which is made by Wix. Thanks to the support of the Miata community this test is costing me very little. If it weren't for encouragement from fellow enthusiasts and their donations, this test would have taken much longer and probably would not have happened at all. The price of gas and lack of time I have thanks to my job and school sure didn't help though.
Pressure Drop Test #1
Pressure drop testing is now complete for each filter. The test measured the differential pressure from the atmosphere including the stock Miata air inlet pipe, airbox and across the filter. The pressure port (actually a vacuum port due to pressure loss) was attached to airbox just above the air filter. The air flow in the stock Miata flows through and inlet pipe to the bottom of the airbox and up through the filter and then through the air flow meter etc. A tygon hose (clear plastic tube) was attached the pressure port and routed to the manometer inside the car. I had my friend and coworker, Matt, ride in the passenger seat and record all data. Each filter was tested a minimum of 4 times. All of the filters were tested on the same day during a 3 hour span limiting any effects of atmospheric conditions. The 3 hour period included a much needed stop for a late lunch and beverage. Any other filter pressure tests will be conducted using one of the filters from this test as a control filter (most likely the paper filter). All of the measurements in inches of water were taken at 6500 rpm at WOT in 2nd gear while climbing hills locally in western WA. In all 22 WOT runs were made and 22 data points taken. 4 data points were taken for 5 of the filters. Due to an ambiguous result on run #4 for the Amsoil filter, two more data points were obtained. All of the data will be presented in the chart below. All comparisons will be made using an average of all data points taken (4 data points for 4 filters and 6 data points for one).
Chart won't transpose - go to link:
http://www.bobistheoilguy.com/airfilter/airtest2.htm
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#2
Here are the results of the dyno run for the BenFer Performance CAI. The dyno tests were conducted at Dyno-Pro in Denver. The overall temperature of the facility was around 80 degrees Fahrenheit and the altitude of the city is about 5300 ft. above sea level. Other than that, no other variables were evident that would influence the dyno results either way. During testing, the conditions did not change. That made for equal playing ground for both intakes. Bear, the dyno tech and professional sprint
car driver, used a Dynojet chassis dynometer which measured RWHP. The initial base-line test run was done with the BenFer CAI with K&N filter upgrade since it was already installed. Keep in mind that no other performance upgrades were utilized during these runs. This test was conducted using the intake alone. We did four runs with the BFP CAI and four with the stock air box. As you can see in the test results, the max torque of 164.1 ft. lbs. was achieved at approximately 4300 RPM with a significant gain of nearly 10 ft lbs of torque and 7 HP increase over stock. The BFP maintained an increase in both HP and TQ across the power band. Even in the higher RPM range at around 5500 RPM, the BFP CAI measured 157.8 over the stock 155.4 ft lbs tq. I was thoroughly impressed with these results. When the OEM air box was reinstalled and tested, you could immediately hear the difference between the two. The stock intake sounded as if it was gasping for air compared to the distinguished, highly audible and throaty roar of the BFP CAI. It was like night and day. During real world everyday driving, all I can say is that you can definitely feel as well as hear the difference. The car is a lot quicker off the jump. During a launch at 3500 RPM, the throttle response was incredible. The low-end torque can definitely be felt. At higher speeds, the engine feels much more aspirated and is pulling much harder. I would go out on a limb to say that due to the colder outside temperature, tq and hp are increased even more than the numbers posted.
Overall, this is a great intake that can be had at an exceptional value. I would recommend this to anyone who is looking for a less expensive alternative to Dinan, ECIS or Conforti CAIs. On top of being able to upgrade to a K&N filter, AEM bypass and your choice of 4 custom colors, you get most bang for the buck. I hope this review will satisfy those interested in this intake. I’m a very satisfied customer.
http://www.bimmerfest.com/forums/showthread.php?t=19004
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Like I said earlier. Its just a stupid air filter but if it is comparable in cost and it flows better. Why not use it? (trail dirt)
It may not turn your truck into a race car, but if it tweaks your throttle response and adds just a little bit when you are winding it out then why not? What's so bad about wanting a little more for next to nothing?
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