K&N air filters
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K&N air filters
i'm in europe where 1 million mile K&N filters retail for the same as a stock mazda item , i've seen little on the club site on air filter up-grades , are there any club members with experience of K&N filtration?
See the 2nd thread in my signature. There is a section dedicated to intakes, of which filters are part of the same system.
https://www.rx8club.com/rx-8-discuss...rx-8-a-233937/
https://www.rx8club.com/rx-8-discuss...rx-8-a-233937/
Intake
(can cause warranty hassle)
The OEM intake is really VERY good. The only 2 aftermarket intakes that can boast a power improvement are the Mazdaspeed and AEM. Which happen to be the exact same thing, just with different logos. That intake can give you a very slight bump in power. And I mean very slight. Within the 2% error margin of modern dynos. (2% of 180rwhp = 3.6hp). There are a few other intakes that are net equal to the OEM intake, but not many. Every single other intake than this handful, from K&N to ebay kits, cold air and ram air, complicated and simple, every single one will cause you to lose power. This is because they do not have the proper R&D into how the air flows into our engine. They just fabricated a tube, made a port for the MAF, and jammed an air filter on the end. The air becomes heavily disrupted, the MAF can't read it right, and the ECU believes what the MAF is incorrectly telling it, causing the ECU to over and/or underfuel the engine all over the rev range. Even removing the OEM screens can cause power loss, since those screens are very well designed to straighten the air flow and smooth it down considerably. They aren't there to 'catch rocks'. Just to straighten the air flow.
The filter isn't even bad. There is FAR more breathable surface area on the OEM air filter than nearly every intake kit out there. The OEM filter is NOT a restriction on the air flow. The K&N drop-in panel was dyno'ed by Speedsource to show a consistent 1HP increase vs OEM. However, the K&N's filtering is substandard, and in Daytona races (Grand-Am ST class), they were losing engines to sand ingestion. (Reference: https://www.rx8club.com/tech-garage-...1/#post3849277) 1HP is not worth that risk, especially if you are paying for it. Stick with OEM. The only solid reasons to go after market are:
- the subjective reason of "I like the sound"
- the cooling reason of removing the OEM air box to improve air flow from the radiator
- or the improvement in how easy it is to get to any items under the OEM air box.
(can cause warranty hassle)
The OEM intake is really VERY good. The only 2 aftermarket intakes that can boast a power improvement are the Mazdaspeed and AEM. Which happen to be the exact same thing, just with different logos. That intake can give you a very slight bump in power. And I mean very slight. Within the 2% error margin of modern dynos. (2% of 180rwhp = 3.6hp). There are a few other intakes that are net equal to the OEM intake, but not many. Every single other intake than this handful, from K&N to ebay kits, cold air and ram air, complicated and simple, every single one will cause you to lose power. This is because they do not have the proper R&D into how the air flows into our engine. They just fabricated a tube, made a port for the MAF, and jammed an air filter on the end. The air becomes heavily disrupted, the MAF can't read it right, and the ECU believes what the MAF is incorrectly telling it, causing the ECU to over and/or underfuel the engine all over the rev range. Even removing the OEM screens can cause power loss, since those screens are very well designed to straighten the air flow and smooth it down considerably. They aren't there to 'catch rocks'. Just to straighten the air flow.
The filter isn't even bad. There is FAR more breathable surface area on the OEM air filter than nearly every intake kit out there. The OEM filter is NOT a restriction on the air flow. The K&N drop-in panel was dyno'ed by Speedsource to show a consistent 1HP increase vs OEM. However, the K&N's filtering is substandard, and in Daytona races (Grand-Am ST class), they were losing engines to sand ingestion. (Reference: https://www.rx8club.com/tech-garage-...1/#post3849277) 1HP is not worth that risk, especially if you are paying for it. Stick with OEM. The only solid reasons to go after market are:
- the subjective reason of "I like the sound"
- the cooling reason of removing the OEM air box to improve air flow from the radiator
- or the improvement in how easy it is to get to any items under the OEM air box.
I'm actually one to disagree here. Obviously it will filter worse, any filter that allows more air will... that's sort of implied. I'm also going to go so far as to say the gains to be had from other kits such as Racing beats intake, is simply due to changing the OEM panel to an oil based K&N filter that flows more/filters less.
Up to you if you want a dirtier engine versus more power - not to say that the OEM is pretty good as is...but I choose more power and more frequent oil changes.
Up to you if you want a dirtier engine versus more power - not to say that the OEM is pretty good as is...but I choose more power and more frequent oil changes.
This is not quite true. You can have a tube with no filter that will allow in much greater particles, but flow much less air because it's only half an inch in diameter. Many ways to increase a filter's air flow without compromising the filtering capacity, like making the filter "deeper", but still of the same material.
Well, yeah, if you don't change the filtration area then increasing flow can only be done at the cost of filtration ability. I understood that bit.
I was just clarifying your point for accuracy since most aftermarket intakes do not use the OEM filter, but still have K&N filters, so there isn't an equality in the filtration area to begin with. And it is theoretically possible to fit a larger paper filter into the OEM air box that will increase filtration area.
However, since the OEM paper filter is sufficient flow for the 450hp 3-rotor RX-8s in Grand-Am, there isn't anything tangible that we can really improve on for our street cars in this area.
I snapped this picture over the weekend at Lime Rock. This is the #42 Sahlen's RX-8
Yes, they have the intake inlet in a gap at the top of the hood, pulling in air from the base of the windshield.
I was just clarifying your point for accuracy since most aftermarket intakes do not use the OEM filter, but still have K&N filters, so there isn't an equality in the filtration area to begin with. And it is theoretically possible to fit a larger paper filter into the OEM air box that will increase filtration area.
However, since the OEM paper filter is sufficient flow for the 450hp 3-rotor RX-8s in Grand-Am, there isn't anything tangible that we can really improve on for our street cars in this area.
I snapped this picture over the weekend at Lime Rock. This is the #42 Sahlen's RX-8
Yes, they have the intake inlet in a gap at the top of the hood, pulling in air from the base of the windshield.
You also have to understand that believe it or not, racing conditions are much more worse for debris, dust, and other crap than simply driven on the street, even with contruction zones and varying weather. You need that extra protection, whereas on the street, well depending where you live, you can easily get away with an aftermarket filter without worry.
However, those who spend upwards of over $300+ on intake system for our cars... complete waste of money. Simple drop in filter for the streets does the trick for me!
However, those who spend upwards of over $300+ on intake system for our cars... complete waste of money. Simple drop in filter for the streets does the trick for me!
Yes, race conditions are different. However when it comes to particulates, there are certainly street conditions out there that have far worse conditions than race tracks. Anything next to a windy beach, for example. Which includes most of populated Florida.
2009 RX-8 Touring
Joined: Oct 2009
Posts: 574
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From: Manassas, VA USA
I use a K&N filter in my RX-8. I think it's still on its original coating of oil; last time I checked it, it still looked pretty clean, so I flipped it upside down and reinstalled it.
I use K&N filters just because they're reusable, so I don't have to throw them away every year or so. Things that are pointlessly disposable irritate me. I don't really care if it produces more horsepower.
I use K&N filters just because they're reusable, so I don't have to throw them away every year or so. Things that are pointlessly disposable irritate me. I don't really care if it produces more horsepower.
I don't understand why this is always such a debated issue. I have a k&n filt in my box and plan on cleaning the filter every oil change. Not that big of a deal and sorry but the people that are all for the oem filter, do you have physical proof? Dyno tests showing now dramatic increase in power or me and the k&n group showin more dirt particles in the intake? Just wondering.
TROLL
Joined: Jun 2010
Posts: 399
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I don't understand why this is always such a debated issue. I have a k&n filt in my box and plan on cleaning the filter every oil change. Not that big of a deal and sorry but the people that are all for the oem filter, do you have physical proof? Dyno tests showing now dramatic increase in power or me and the k&n group showin more dirt particles in the intake? Just wondering.
I checked out their site & got a security warning.
Don't know what that's about.
Hi RIWWP,
I'm sorry if I'm being obtuse, I'm easily confused.
OEM in this case is any aftermarket filter designed to replace original one?
I was thinking literally original manufacturer.
I was getting mixed up reading about guys re-using & spraying them with oil instead of just replacing them like I always have.
Thank you for your patience.
I'm sorry if I'm being obtuse, I'm easily confused.
OEM in this case is any aftermarket filter designed to replace original one?
I was thinking literally original manufacturer.
I was getting mixed up reading about guys re-using & spraying them with oil instead of just replacing them like I always have.
Thank you for your patience.
I have already read that. About them loosing like two engines and he loves the paper filters up and down but I am talking of just normal day for us using the 8 as a daily driver. Which then it still does depend what type of terain you drive in. But I was refering to that. And my mistake I ready the 1+ hp dunno why I mentioned the dyno test.
Hi RIWWP,
I'm sorry if I'm being obtuse, I'm easily confused.
OEM in this case is any aftermarket filter designed to replace original one?
I was thinking literally original manufacturer.
I was getting mixed up reading about guys re-using & spraying them with oil instead of just replacing them like I always have.
Thank you for your patience.
I'm sorry if I'm being obtuse, I'm easily confused.
OEM in this case is any aftermarket filter designed to replace original one?
I was thinking literally original manufacturer.
I was getting mixed up reading about guys re-using & spraying them with oil instead of just replacing them like I always have.
Thank you for your patience.
OEM = Stock = Original Manufacturer
Aftermarket MIGHT be the same design and structure as the original, but still isn't really "OEM". For example, there are alternators out there for us by Beck and Arnley, Bosch, and Denso (and probably more than that). These aren't really OEM, even though they are designed the same and will fit.
Then again, Aftermarket MIGHT still be actually OEM. Car manufacturers rarely build components themselves. They outsource the specific components to individual manufacturing companies. For example for those alternators, I think Denso makes the alternators that get installed at the factor (unsure). Other examples are:
- Most of our electronics in the car are made by Mitsubishi's electronics division
- Our shocks are made by Bilstein or Tokico (depends on your car's trim/package/year)
- Our clutch is made by Exedy
- Our plugs and wires are made by NGK
Therefore it is possible to get "OEM" or "stock" parts that are from an aftermarket non-dealer source. Nearly every part in the car is like this.
You can buy the "OEM" filter at most auto parts stores and consider it actually OEM.
I have already read that. About them loosing like two engines and he loves the paper filters up and down but I am talking of just normal day for us using the 8 as a daily driver. Which then it still does depend what type of terain you drive in. But I was refering to that. And my mistake I ready the 1+ hp dunno why I mentioned the dyno test.
I simply don't understand why anyone would be willing to take even the slightest risk here. 1hp is the ONLY advantage, and isn't even something anyone can feel.
Last edited by RIWWP; Apr 22, 2013 at 11:01 AM.