K&N air filters vs. cold air intakes (Not brand specific)

[Don M]

I've been stuck at home with a nasty head cold, and haven't been able to do much more than roam the internet. Lacking anything better to do, I decided to research K&N air filters-I even found a really cool video about how K&N filters (and their side brands - Spectre/Airraid etc) are made.


Anyhow, I typed in "K&N air filter vs Stock" and hit the mother load-videos galore ...


The interesting thing is that a large majority of the vids (the ones not hating on the K&N-which were mostly posted by the clueless ones) claimed that a K&N drop in filter outperformed many CAI set ups Some of the tests were HP based and others were MPG based. I even found a few that claimed the paper stock filter outperformed them both ... on a dyno.


All in all, it made for an interesting day of otherwise being sick & bored out of my mind.

[PA DETAILER]

In todays vehicles I would never run a OILED filter period. Too many results of fouling the MAF sensor with oil. DRY FLOW is the way to go. I have a AIRAID drop in on my Xterra. Cleaning is a breeze. And no oiling.

[Don M]

In todays vehicles I would never run a OILED filter period. Too many results of fouling the MAF sensor with oil. DRY FLOW is the way to go. I have a AIRAID drop in on my Xterra. Cleaning is a breeze. And no oiling.

Interesting you should bring that up ... in a video from K&N, they dispute that claim and offer compelling evidence to the contrary:

K&N Filters do NOT foul MAF Sensors

Also a very interesting video:

How K&N Filters are Made

[BudgetPlan1]

Absent a tune to go along with it (in which the tune is likely 95% of the 'difference') I've found underhood CAI's to be mostly noisemakers, based on experiences with Mustangs and Corvettes. The true value is actually bringing in cold air, thus lowering IAT's and reducing the PCM's need to pull timing to avoid detonation. The 'more air' theory alone is, IMO, relatively pointless, absent other modifications (i.e. exhaust) to maximize the increased flow of inlet air.

The Corvette world does have a few that make most of the gains from re positioning the initial air inlet (Callaway Honker, Vararam) to draw in true 'Cold Air' but absent that critical factor, the 'C' in CAI is mostly marketing if it's just a larger filter still positioned underhood, heat shield or not.

They do sound cool and look neat underhood though, and that was enough for me to buy in a few times.

[TTQ B4U]

In todays vehicles I would never run a OILED filter period. Too many results of fouling the MAF sensor with oil. DRY FLOW is the way to go. I have a AIRAID drop in on my Xterra. Cleaning is a breeze. And no oiling.

^^ this. IMO unless you're in a forced induction situation, most of today's vehicles have more than enough air flow with dry paper filters. CAI's are great and all but the weak spot on most intake system is the tubing and throttle body size. Case example was my S4. The last limiting factor for power on my car was upping the size of the throttle body. It was actually being held back because it couldn't push enough air. The upgrade is 25% larger than stock and being my car was already tuned for it, I could have added 50awhp and dropped my intake temps just by adding the new $1,600 intake. I still miss that car but I don't regret it as for me I would have also had to add nearly $3k in Catalyst work to allow for it to run such a set up.

The biggest advantage is keeping smooth airflow. Even that can be problematic on some vehicles. Case in point my Redsport.....Stillen and many other intake companies have yet to find a superior than stock set up for the twin turbo set up on this car. Their systems are cool looking and sound great (although aren't necessary for the sound of turbos spooling) but they are causing CEL's and power loss/ bogging. The systems on this car are so complex and tightly tuned that they are not proving helpful at all. The power I put down was on my stock intake.

Another aspect on boosted cars, especially turbos, are the efficiency ranges of said turbos. Again, Redsport wise, this thing has two smaller snails that I'm already at the edge of the efficiency range up top with. A few simple bolt ons like a down pipe would allow it to breath better but they would then be nothing more than blow torches up top. Sometimes restrictions are in place for a solid reason. More air in means the need for more air out and when that happens there's also a need to balance out the cooling system both for intake temps and to monitor exhaust gas temps. Failing to address any of those points will only lead to more problems.

Cliffs: Don, you have nice car, but an intake on a N/A 3.6l V6 isn't going to drive much in the way of gains.

[RTexasF]

I bought in to the K&N crap so many decades ago they had to be ordered from England!! I put them on or in every car I owned for many many years and what did I get? NOTHING, ABSOLUTELY NOTHING other than a very large reduction in wallet contents. They ain't what they are cracked up to be.

[Don M]

I haven't noticed any of the negatives on the Camaro, just a 2 to 4 MPG increase highway and slightly smoother off idle acceleration.

[JDGolden]

My Camaro had a K&N filter in it when I bought it (filthy) with a stock air box assembly. I added an FTP air lid and a Wix paper filter. I still have the K&N, not sure what I'll do with it.