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K & N Air Filter, Hype or not?

2895 Views 24 Replies 21 Participants Last post by  JerryC
Does it REALLY pay to put in a K &N air filter in my 5.0 Mustang? The original air filter looks fine( 6000 miles) and I was wondering if any really notices anymore 'power' from the engine?
I see that Amazon has them for about $40 or so.
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yes, they work great and will save you a fortune in the long run...I've had them in all my cars for 20 years...when it's dirty you just clean and re oil it.
My understanding is the only possible power increases you will see are high up in the RPM band.
Does it REALLY pay to put in a K &N air filter in my 5.0 Mustang? The original air filter looks fine( 6000 miles) and I was wondering if any really notices anymore 'power' from the engine?
I see that Amazon has them for about $40 or so.
The information I received from the local dyno shop is, no, you won't notice an increase in power. You can save money by using one, but can also coat the MAF sensor with oil if you're not careful though. I'd wait until you need one before buying if you're so inclined.
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My factory filter was "dirty" at 5K, that was was when I put the K&N in. At 10K I cleaned the K&N and it was full of crap too. At this rate the K&N will pay for itself by 20K miles on the car, 25K if you figure in the cleaning kit.

The most I've seen of a K&N vs stock filter was 4HP, but the stock filter had several thousand miles on it. I'd say that the K&N isn't going to net any HP over a clean/new paper filter. This may have as much to do with the airbox/fresh air intake as it does with the filter.
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a lot of people who buy the drop in filters end up getting a cold air intake afterwards (myself included). So before you spend the $40, ask yourself if you have any desire to get the CAI beforehand.

Also, i am quite "particular" about my engine, so i found myself stressing over how much oil i put on it. Too much and it coats the MAF sensor and causes issues, too little and dirt gets through.

Thats why i went with a dry flow air filter and am quite please with it. Just trying to help you to make just 1 purchase instead of several, thats how modding can add up really quickly
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The information I received from the local dyno shop is, no, you won't notice an increase in power. You can save money by using one, but can also coat the MAF sensor with oil if you're not careful though. I'd wait until you need one before buying if you're so inclined.
Yes most won't feel increase in power but thats not the only reason why poeple buy them. Even dirty K&N still outflows new paper filter then after paper filter gets dirty it drops of alot choking air flow. If you over oil it can get on MAF sensor that problem comes from poeple thinking more oil is better.
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My factory filter was "dirty" at 5K, that was was when I put the K&N in. At 10K I cleaned the K&N and it was full of crap too. At this rate the K&N will pay for itself by 20K miles on the car, 25K if you figure in the cleaning kit.
You are NOT doing yourself a favor by cleaning the K&N at such short intervals.

A K&N filter works better DIRTY, up to a point.

In extremely dusty situations, you might need to clean the filter at 25K, most won't need cleaning until at least 50K.

If the filter is getting large debris in it between cleanings then just knock it out but don't wash and re-oil until it is really necessary.

This is the biggest benefit of the K&N, it will last virtually forever.

And if you are careful about how you oil it after cleaning then you won't have any MAF sensor problems.
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Get the K&N it is an easy bang for the buck mod
I doubt there is a power increase, but I did notice then when I installed it on my v6, it definitely changed the engine note for the better. A bit throatier in sound.
You might notice a placebo effect, but nothing else.
This dyno by Brenspeed shows there was no measurable difference between K&N drop in and the OEM filter. I think the drop in filter is great for saving money in the long run on filters but as other have said, you have to careful when you reoil.

http://www.allfordmustangs.com/foru...panel-vs-stock-filter-2011-mustang-5-0-a.html
You are NOT doing yourself a favor by cleaning the K&N at such short intervals.

A K&N filter works better DIRTY, up to a point.

In extremely dusty situations, you might need to clean the filter at 25K, most won't need cleaning until at least 50K.

If the filter is getting large debris in it between cleanings then just knock it out but don't wash and re-oil until it is really necessary.

This is the biggest benefit of the K&N, it will last virtually forever.

And if you are careful about how you oil it after cleaning then you won't have any MAF sensor problems.
Thanks, I had read that when I got the filter.

They may be right, but I'm not going to use their guidelines any more than I am going to use the Ford guideline of 10K between oil changes.

"We recommend that you visually inspect your filter once every 25,000 miles to determine if the screen is still visible. "

Yeah, not waiting until I cant see the screen to clean it. If I clean it at every oil change 5K I wont forget and it should be set for best performance (HP). I wouldnt wait for my paper filter to clog before I changed it either, they were dirty at 5K.

What I might do is to knock or vacuum out the big chunks every 5k and clean every 10K, have to see how much it collects.

I'd like to see some dyno runs done with a K&N that has not been cleaned, at 5K intervals to 50K. the cynical side of me thinks that 50K is pure marketing hype, oh the car will run with a filter with much dirt in it, but how well will it run?
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I put the stock filter back in because I couldn't see or feel any gains with the K&N.
Didn't know the K&N needs oiling. Sounds like my '57 Caddy oil bath air filter. I'll stick with regular paper filters every 10,000 miles and not fuss with something that won't improve anything except your ego, as stated here. Thanks for everyone's input
you wont get any real power gains but as mentioned you will save you a fortune in the long run by switching to the K&N - which means less waste and more $ for other car related toys.
I picked up 1 MPG better gas millage in my 2001 GT after K&N. I did not notice any gain of MPG on my 5.0. They say you do but I don't know. You don't feel any power increase because if there is any, it is very minimal (less then 4 HP).

You will save $$$$ in the long run over re buying paper filters. The oil your MAF sensor is a myth. You can probably find it on Mythbusters. LOL. :hihi:
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I do not have experience with the maf on this car yet but my previous cars were very sensitive to the oil from K&N filters. Throttle response worsened and even a/f readings were skewed because the maf was hit with even a light coat. I was careful to use as little oil as possible and used extended drying times.

A few sprays of maf cleaner or electronic parts cleaner that is safe for plastic would get the throttle response back and a/f back in line. Maybe this maf is less sensitive than my experience but I would rather not deal with it so I stick to dry filters. That and the increased silica that always seems to show up on an oil analysis when K&N is used for the air filter.
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In general a mod that costs under $100 on it's own will do nothing you can feel in the seat.... and likely nothing at all. Real power upgrades cost real money. I don't care if it's a Mustang or a Civic or an F-150. Same for mpg improvers. It's just something to separate you from your money.

But, the k&n filters DO last a very long time ;)
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I read this thread months ago, and decided to buy the K&N as an experiment. I've had it on my car for a few thousand miles now. Here is what I've found:

-NO noticeable seat-of-the-pants gain. Induction feels exactly the same. Even at High RPMs/speeds.
-NO noticeable change in sound at idle or WOT
-NO change in MPG

I would never know its there if I didn't install it myself. The only gain i got was "piece of mind" knowing the reputation of K&N flowing better than stock. And I'm taking that with a grain of salt now.

As one of the moderators stated earlier, a lot of people who buy K&Ns end up getting a CAI. Now i KNOW why. Time to see what this whole "CAI" thing is about. :yelpleased:
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