Any thoughts on K&N Filter Kits?

[Don]

Here is the article...they don't specifically mention how much MPG was gained, but in the print versions (which went past part III) they did mention the number 40 when talking MPG Sport Compact Car article

[Don]

Originally posted by Aurora40
Hey Don,

I agree with the similar analogy. It's harder to pull air through, and there is more pressure drop. Of course, vacuum can only be so much in earth's atmosphere, where pressure can be quite high. So an exhaust can be a lot more punishing if it is restrictive...

But anyway, here is where I see that analogy fall apart. At wide-open-throttle, you are right on. Less restriction, and also less pressure drop means more air in the cylinder. But at part-throttle, you are creating vacuum with the throttle-blade. There will always be a restriction, as this is what prevents the motor from cranking out full-power all the time. So a freer-flowing air filter won't do anything, as you will create the same amount of vacuum and allow the same amount of air in via the throttle-blade while cruising as you always did. And the ECM will mix in the same amount of fuel with that air.

There is no similar analogy to the exhaust because you never intentionally induce more pressure via throttle blade (with rare exception) to choke the engine.

But the performance filter flows better through the entire rev range of the engine making it easier for the engine/computer to keep things 'calibrated' so to speak. This is one reason the K&N gives better throttle response, as soon as the plate opens to allow more air in the K&N lets it flow with stock filters there is a momentary pause as the engine has to fight the restrictiveness of the paper filter before air flow increases.

[mirrorfinishman]

Do high flow proformance filters allow larger particles of dirt to flow into the engine?

[2000]

Originally posted by mirrorfinishman
Do high flow proformance filters allow larger particles of dirt to flow into the engine?

oh-oh, theres another couple of pages added to this thread.
I have read conflicting reports on this, however I have never been bit, so I'm comfortable with them. (at least k&n as thats all I've ever used.)

[Aurora40]

Originally posted by Don
But the performance filter flows better through the entire rev range of the engine making it easier for the engine/computer to keep things 'calibrated' so to speak. This is one reason the K&N gives better throttle response, as soon as the plate opens to allow more air in the K&N lets it flow with stock filters there is a momentary pause as the engine has to fight the restrictiveness of the paper filter before air flow increases.

Right, you are still talking wide-open throttle, though. Through the whole RPM range. But fuel economy gains will come at part-throttle.

So picture this, an engine at 25% throttle opening cruising along with a stock filter. Suddenly the filter is replaced with a K&N. Now, if it flows more air or flows with less pressure drop, then more air gets into the cylinder. So if there is more air in it, then you either add more fuel, or run more lean. The ECM will not allow it to run more lean as it has an ideal range it wants to run in. This is similar to suddenly driving into an area of cooler denser air. So the engine will either start to speed up, or you will back off the throttle, thus causing more pressure drop, and allowing exactly as much air into the cylinder as before to get back to your same cruising speed, and the engine will put exactly as much fuel in as before, thus getting the same economy.

It just doesn't add up to me. I think for better economy, an exhaust can help. Changes internally can help. Reducing driveline (including tires) losses can help. And mostly, driving more carefully can help. I just can't see a K&N filter helping. It doesn't make sense to me.

If you want more performance, then a filter that lets more air in the engine will definitely help.

[Don]

Originally posted by Aurora40
Right, you are still talking wide-open throttle, though. Through the whole RPM range. But fuel economy gains will come at part-throttle.

So picture this, an engine at 25% throttle opening cruising along with a stock filter. Suddenly the filter is replaced with a K&N. Now, if it flows more air or flows with less pressure drop, then more air gets into the cylinder. So if there is more air in it, then you either add more fuel, or run more lean. The ECM will not allow it to run more lean as it has an ideal range it wants to run in. This is similar to suddenly driving into an area of cooler denser air. So the engine will either start to speed up, or you will back off the throttle, thus causing more pressure drop, and allowing exactly as much air into the cylinder as before to get back to your same cruising speed, and the engine will put exactly as much fuel in as before, thus getting the same economy.

It just doesn't add up to me. I think for better economy, an exhaust can help. Changes internally can help. Reducing driveline (including tires) losses can help. And mostly, driving more carefully can help. I just can't see a K&N filter helping. It doesn't make sense to me.

If you want more performance, then a filter that lets more air in the engine will definitely help.

But the engine STILL doesn't have to work as hard to get the air IN, even at part throttle so you are taking some of the effort out of getting air into the engine (much like an exhaust takes effort out of removing air from the system).

For example, say it takes 10 HP for an engine to pull air through a stock filter, but only 5 HP to pull air through a K&N.

Too, say it takes 100 HP to cruise at 60 mph. With the stock filter, the engine has to use enough fuel to produce 110 HP to maintain 60 MPH. With the K&N filter, the engine only has to use enough fuel to make 105 HP. Therefore, the fuel needed to produce the 5 extra HP the stock filter required is no longer being used and remains in the gas tank, meaning the engine is using 5% less fuel to do the same work.

**Disclaimer, I know my numbers & percentages are off, the numbers just came with the monkeys that flew out of my....wait family forum, never mind. But my point is the same, granted we're not talking huge percentages, but I'm hoping this makes things clearer.

[gb387]

Aurora40 AND Don both have some good thoughts on the subject.... now I am really confused?!?!

[Don]

Originally posted by gb387
Aurora40 AND Don both have some good thoughts on the subject.... now I am really confused?!?!

I suggest just getting the filter/intake kit, it definately won't hurt anything and if nothing else, you'll save money by not having to buy replacement filters all the time. Plus the kits with the exposed filters make a cool sound

[DIESEL]

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I installed the Filtercharger as pictured into my 2000 GMC Sierra, and immediately bettered my mpg by 2+, and horsepower measured by acceleration quickness was well noticed.

The unit works by flooding in cold (not heated under hood) air, which is denser, and allows much more of it - which uses fuel better, as long as the exhaust is free flowing, which usually means an aftermarket like Flowmaster. I don't recommend Gibson, they do not stand behind their product - mine rotted off after 1 year, and they told me that was common, and I could spend another 200 dollars for parts!

I also added the Hypercharger programmer, and with the combination of the three, I can waste a lot of tires.

I get about 15mpg, with 10 ply 285-16's, which is much better than the 10 I was getting.

[r111]

On our race car by using a K&N air filter and a K&N extreme lid we picked up a tenth in the 1/4 mile over using no air filter. When we tried a AC filter it slowed the car up several hundreths over using no air filter. We use K&N on all our street cars. Under normal driving conditions we don't see much difference over a AC filter.

Stu

https://www.rinehartsracing.com

[LT22]

Has anyone heard of the tornado. Im not sure how it works but yu install it in your car, suppose to be easy installation gives you 1-2 more mpg not sure if it reduces performance. Well majority of you guy have american cars IMO *****, because they need a lot of maintenance K&N Intake kits are perfect for american cars and to top off with the perfect cat-back exhaust or headers BORLA, can never go wrong with BORLA and its MILIION MILE WARRANTY.

[2000]

Originally posted by LT22
. Well majority of you guy have american cars IMO *****, because they need a lot of maintenance

??????????????????
as opposed to what?

[Tim Lingor]

OK guys, I have kept a watchful eye on this interesting thread. But, if people start making derogatory comments/generalizations, I will have to intervene.

Please show the proper courtesy and respect to one another...

Thanks,
Tim

[Aurora40]

Originally posted by DIESEL
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The unit works by flooding in cold (not heated under hood) air, which is denser, and allows much more of it - which uses fuel better

Well, I guess we'll just have to agree to disagree. Cold air doesn't use fuel "better". Cold air at a given pressure has more mass, thus there is more oxygen and more fuel can be burned in it. However, that doesn't affect economy, that affects the amount of power you can make, which is directly related to the amount of fuel you can burn.

As I said, I don't doubt on some cars they can improve the ultimate power the car can make, either by creating less pressure drop, or by relocating the intake area to bring in cooler air.

So I'll bow out of the coversation. I will say if you want better economy, the best fix is your right foot. K&N filters are cheap, but the filterchargers are not. Either way, the best way to find out what it will do is to try it.

[LT22]

Im sorry wrong wording I choose imported cars instead of cars manufacterd on american soil. I work at a mechanic and the majority of american cars come in have engine problems. They just need a lot of maintenance. Dont get me wrong I still love the american muscle. Especially my all time favorite Dodge Viper. IMO... I believe american technology lacks the technology in foreign made vehicles. They are poorly built, not so reliable. Toyotas in the other hand are very reliable. What im trying to say is that american vehicles need to focus more on MPG than HP. They have a missing link when building there engines. Im not trying to put anyone down or anything its just my opinion.