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Anyone running a Cold Air Intake?


traxiii

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Just noticed a air filter thread in the Mods. folder, so if the moderator wants to take this down, I'm fine with that.

 

K&N says their CAI makes 5+ horsepower and an increase in mileage. Has anyone here installed one?

Edited by traxiii
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Plenty. 5+ hp is optimistic. 2-3 is more likely - not enough to tell the difference either way and only at WOT.

 

There is no reason why it would increase fuel economy either on a modern vehicle. More air = more fuel, not less. If you notice nobody has any test data showing a mileage increase - just a "you may see a mileage increase". Don't count on it.

 

For reference, a guy stuffed a cloth diaper in his airbox severely limiting the amount of airflow. He had very little power but his mpg actually went up slightly, not down. The whole "letting the engine breathe easier yields better mpg" is a myth on modern cars. On carburetors - sure. On modern EFI with MAF sensors - nope.

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I guess you've never heard of volumetric efficiency? Try breathing through a straw and tell me how much harder you have to work to breath. Now I don't claim to know how the 2.0L EB is mapped and what works to get more mileage other than a light foot, but I do know that not having to suck as hard is going to cool things down. Also the easier it is to breaths, the more efficient the system creating boost, and at making more power. Replacing the convoluted tubes with smooth tubes entering the throttle body lessens eddies and turbulence the MAF sees, helping it meter the system better to boot. I think people might be more apt to use more throttle since they can hear the air flowing and possibly feel it in the butt dyno, that would be my explanation for any loss of mileage rather than what you present.

 

I haven't ever dynoed a car before and after, with one of their systems, but know places that have, have you? They seem to get the same or very close numbers to what K&N claims, and for the Edge 2.0L EB they claim 5.45 HP to the wheels, just sayin'

 

P.S. I work in a wind tunnel, literally, dealing with jet inlets and all else dealing with aerodynamics. Of course we don't start measuring things until we reach Mach 0.4.

Edited by traxiii
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If all Ford needed to do to get a significant mpg gain was put in a smoother intake - which would only cost them a few bucks in volume - don't you think they would have done it already? They already spend millions of dollars for a fraction of 1 mpg gain.

 

The only thing that matters is the density of the air reaching the combustion chamber. The computer adjusts the amount of fuel accordingly. More power? More fuel. It doesn't matter if the throttle plate is 40% or 50%.

 

K&N has plenty of dyno graphs showing power increases. Where are the same types of before and after tests showing mpg improvements? If they existed they would be published because that would be a much bigger selling point than a few hp.

 

Read this. This is a scientific test, not a company trying to sell products.

 

http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf

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  • 3 months later...

It's really about getting more air to the throttle body. If you have more air that equals more power with more fuel. But...you now have more available horsepower to keep your vehicle travelling at 65mph which in turn lets you back off the throttle a little to stay at 65mph in turn increased fuel mileage. I travel long distance (2000 miles) in various vehicles and I always take out the air filter on long trips but I check my mpg before filter removal and after. Sometimes it's 1-2 better mpg with it removed and sometimes 2-4 mpg better. I know its not good driving without an air cleaner but I'm simulating a free flow k&n intake for my own knowledge. Just saying.

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It's really about getting more air to the throttle body. If you have more air that equals more power with more fuel. But...you now have more available horsepower to keep your vehicle travelling at 65mph which in turn lets you back off the throttle a little to stay at 65mph in turn increased fuel mileage. I travel long distance (2000 miles) in various vehicles and I always take out the air filter on long trips but I check my mpg before filter removal and after. Sometimes it's 1-2 better mpg with it removed and sometimes 2-4 mpg better. I know its not good driving without an air cleaner but I'm simulating a free flow k&n intake for my own knowledge. Just saying.

 

That doesn't make sense. There is no difference between bringing in X amount of air with a filter and 30% throttle or without a filter and 20% throttle. The MAF measures the amount and density of the incoming air and adjusts the fuel accordingly. You'd get more air at WOT so you might see a slight power gain there but it just doesn't make sense that removing the air filter yields better mpg.

 

In fact somebody did a test and actually put a cloth diaper in the airbox severely restricting airflow. Had very little power but fuel economy actually went up, not down.

 

If you're seeing different mpg then it's probably due to a change in your driving.

 

BTW - if you check K&N's website they have actual dyno graphs for power gains, but they don't have any test results related to mpg nor do they make any claim of increased mpg due to a free flowing filter. They simply hint at it. If it was true they would have some actual test results just like they do for the dyno.

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It's really about getting more air to the throttle body. If you have more air that equals more power with more fuel. But...you now have more available horsepower to keep your vehicle travelling at 65mph which in turn lets you back off the throttle a little to stay at 65mph in turn increased fuel mileage.

 

So that's not how engines actually work. The computer will adjust the throttle to whatever it needs to get the amount of HP required to travel at 65mph. The amount of air needed to travel 65mph is always the same, no matter what is in your intake. The total restriction (filter + throttle opening) is what determines the amount of air coming in. So less restriction in the filter means the throttle will close, more restriction in the filter means the throttle will open. But that doesn't matter because the amount of fuel injected will be exactly the same, since throttle position and fuel injection are controlled totally separately on today's cars.

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  • 2 years later...
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In response to running without a filter, Road and Track was testing a modified tuner Viper many years ago and the engine got ruined during testing because the tuner who supplied the Viper decided not to run a filter in it for the testing session. Likewise, this is why I am a huge critic of oiled filters like K&N's. They have really bad filtering efficiency which means that you are going to get larger particles making it through and more of them versus a standard paper filter. That is why many people here are running paper performance and paper conical filters instead of the oiled gauze filters like the K&N and S&B's While they won't let in anything big enough to destroy the engine immediately, it can take its toll on the engine and turbos over time. Numerous third party tests have been done and they show that those oiled filters actually have worse flow once they start accumulating dirt. K&N has also been busted before overstating HP gains. As Alan said, you may be lucky to even gain those couple hp. Just because the factory intake has all sorts of baffles and weirdness to silence induction noise does not mean that it is horribly restrictive. Noise is just noise.

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Filtering efficiency is all relative, simply looking at the MERV ratings for household furnaces is the quickest way to get an idea of what that really means.

 

Look at the table provided in the following link

http://furnacefiltercare.com/performance/merv-ratings/

 

As far as K&N, they claim 96-99% efficiency. 98% for our purposes (gen 1-1.5)

https://www.knfilters.com/efficiency_testing.htm

https://www.knfilters.com/dynocharts/33-2395.pdf

K&N Test Results 33-2395.pdf

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