Reggie

but I think I have seen articles where the OEM filters were better than K&N on this too.

bhvrdr

of course there are exceptions to this based on individual design.

Affastyle2000

I work in the automotive/truck air filtration industry as a sr. project manager. My job is to manage the guys who design this stuff for the truck and light vehicle market - I've worked on applications ranging from Class 8 trucks to Corvettes. In my 10 years in the industry, I've never had a OE ask for a oil air cleaner because it offered better performance.

The reverse is true, as any "claimed" performance increase would be due to the filter passing a greater percentage of dirty air through (non filtered air) to the engine, making the system less efficient at filtration. This is bad. But, let's be honest - the average oil element efficiency (% of dirt filtered) is anywhere from 96-98%. Your average paper or synthetic (or combo of both) filter is in the 99% or higher range. This difference would be a concern if you drove your car in an extremely dirty environment - frequent use on dirt roads, and blowing dust environments, like desert. Most of us stay on road and really not a concern.

Quick history lesson: Oil treated air cleaners like the K&N and BMC originated from the initial air cleaner concepts developed in the early 1900's where Spanish Moss was soaked in oil and shoved into a soup can and clamped over the air intake of tractors. As this evolved, the moss was replaced with various cloths, then oil covered paper. This was common until the 40's and 50's when paper technology was developed to a point where oil was no longer needed to help aid in filtration. Today, nanofiber and synthetic fibers are can be layered into standard paper to create layered filter media that can last up to 150,000 miles or more in on road trucking environments. Nanofibers are able to filter down to 2-3 microns, your average dust particle is in the 30-50 micron range. In other words, oil filter performance is based on technology that is at least 90 years old and replaced nearly 60 years ago in most applications. I worked recently on a project for a big three company where oil was still applied to paper, but in a non serviceable panel filter. It is a carry over product and being phased out. Also it is not a filter you would spray and service on your own. Big difference.

All this being said, the only way to obtain any kind of performance increase in a kit would be to straighten the air flow to the engine. I can see slight improvements being made if a bend can be smoothed out and the path to the turbo simplified, but no gains from a filter change. I'd even caution against this as 100's of hours are spent designing the system and testing to ensure our systems not only meet engine performance specs, initial and terminal restriction - used by the engine mfg to calibrate the MAF, and ambient temperature requirements. If the clean air duct air flow changes, you'll probably foul your MAF - similar to what Umlaut correctly stated with oil residue, but done with creating dead pockets or increased air flow rendering the sensor unreliable.

The air filtration is the most important part of your engine system, any debris that enters the engine can and will cause significant damage. Any gains from an after market element change using "oil treated" will increase air flow by decreasing filter efficiency and filtration performance. While in most on road applications this generally isn't a concern, however, oil filtration technology has been obsolete since the 1950's. In addition, clean air ducts are designed to meet the specific requirements of the engine builder and MAF sensor location is a critical design feature determined by the air flow (CMF) in specific locations within the duct. Any potential gains by replacing this system would be small and would include downgrading the filter performance of your car and creating potential issues with your air sensor system. Also, as Umlaut stated, oil can also be sucked off the element if not serviced properly or under very hard acceleration and onto the MAF fouling the sensor creating an additional issue.

K&N deserves a marketing gold metal, they spend a lot of money selling old technology and everyone knows who they are and what they do. I would be cautious, at best, and put my money towards a proven upgrade. My two cents. Sorry this got long...

Tgr_Clw

tt for later reading.

maaliish

The major reason I have an upgraded intake on my car is because it allowed me to replace my MAF housing with a bigger unit which doesn't have the vanes used to straighten the airflow over the MAF sensor. A panel filter does not straighten airflow which is why our stock MAF housing has vanes (net) in it. Good cone filters have built in velocity stacks which increase and smooth out the airflow allowing removal of the vanes and hence reducing the restriction.

Beanie088

Thanks for the info...

Affastyle2000

1. There is no such thing as a good cone filter, at least in an aftermarket segment. Someone can argue this, but if you compare any SAE test that compares to standard paper filters, it is pretty clear they just don't perform well.

2. "Straight air" is a result of lower restriction on the outlet side of the element (clean air) to the engine, not through filter itself. Any claim that filters "straighten" air and offer better performance is misleading. To explain: Low initial restriction on the filter media (cone) typically means it is less efficient, will load quickly and hold less dirt - creating a high restriction rise over its life, in the end really hurting performance. Panel filters will have a slightly higher initial restriction because they are more efficient. This means that as the filter loads the restriction rise is less over time (as it gets dirty), offering stable and increased performance when compared to the cone filter. When new or clean, a cone element will be less restrictive for a very short time, until it gets dirty and loads. As the filter loads with dirt the restriction rises and remains high, actually hurting performance for the majority of its life. Not to mention it doesn't filter as well leaving your engine at risk. In the end, "straight air" claims through the element itself refers to "initial restriction" and doesn't look at restriction rise, element capacity, or filtration efficiency. These are far more important factors when comparing performance and have nothing to do with "straight air".

3. In a perfect world, we would want to design a long, straight, consistent size reduction and MAF placement of, say 30cm down from the outlet of the air filter for best air flow (low restriction) and MAF performance (in most applications). Instead we're given (if lucky) a fraction of that to cram the entire system into, including the air cleaner. In light vehicle applications MAF placement is usually 3-5 cm from filter outlet - or a 1/10th to 1/6th of the ideal placement. My point here is that given the already small and far from ideal packaging space given to place this system into, any aftermarket add on claiming to offer any noticeable performance increase needs to be looked at carefully. The air system is confined to such a small space it can't be compared to a straight through exhaust system where "straightening" does make a difference. The package size to begin with is just too small, any gains would be minimal, at best.

maaliish

Cone intakes and most good after market intakes have a built in velocity stack which smooths and speeds up the airflow. This is why vanes can be removed from the MAF without throwing a CEL and why my car can run with a bigger less restrictive MAF housing. There is more to the design of the after market filter than just its filtering capabilities (which I agree with you are not all they are advertised to be). Like I said, I didn't get the intake for its performance gains, rather I got it because it allowed me to install other performance upgrades which would not work with the OEM filter/box combo.

Umlaut

^^^ YES! Mod this one up!

Tgr_Clw

Done. Thank you for posting.