- This topic has 3 replies, 4 voices, and was last updated 7 years, 7 months ago by
.
-
Topic
-
K & N high flow filters and all sorts of CAIs are a big industry. All over the forums you read people doing those upgrades. Further, the CAIs claim to straighten the air by having polished tubes and other absurdities. Now here’s my question. I was changing the air filter on my 08 Toyota FJ Cruiser and noticed a secondary filter on the intake right after the air filter. It was kind of dirty (dust) and is made of a pretty fine mesh. Here’s an example although this is not my image:
http://i205.photobucket.com/albums/bb276/gearboxracquetball/20160628_222235_zpsrl3kecpy.jpg
After some Google research, I’ve learned it’s a charcoal filter for emissions so that unburned gasses don’t escape the engine. Further, people like me were asking if it’s hindering air flow and others replied that they’ve done dyno test with the emissions filter in place and removed and showed no different results. The charcoal filter is fixed in place and is neither removable nor meant to be serviced.
So, my question is, how can they market filters like K&N and CAI’s saying they provide more air and more horsepower and at the same time, you can have a fine mesh charcoal filter in place or remove it and have no quantifiable difference? To me it seems like the charcoal filter is a much bigger restriction than say a regular paper air filter and a K&N. To make the question even more absurd, does it make sense to buy new filters or should I just pull the old one, shake it and put it back 🙂
-
Replies
-
In my experience- it’s all BS. In a nutshell, with some disclaimers attached to it.
With new-school (Fuel injection, almost anything with a computer) the engine gets the air it needs, and that’s all it wants. Any more or less, it really makes no difference. Things like traffic, your driving style, time of day, tire pressures, engine break in& condition, and air temperature make the biggest REAL impact. Restriction does not really mean anything when there is a PCM or ECU controlling things, as the ECU/PCM IS a restriction. If that engine isn’t getting that air- you’ll know it PDQ. The CAI benefits are mostly it makes a cooler sound, and looks cooler. I like cooler don’t you? If you REALLY want to make a difference with a CAI- get it tuned with it. Otherwise waste money on cool stickers. I get more attention for my stickers from people than my engine.
With old school, the idea means something. These would be carburetors. I hear arguments about it even with this area, so I will be quiet so I don’t provoke something.
Most car guy’s I know tend to leave it stock unless they want to really mess with things. We are more concerned with what goes in WITH the air, and where it ends up. Than how much air, and MPG’s. IF that CAI really made that big of a difference on your MPG’s- it would come stock.
Naturally aspirated. There’s something there.
Turbo.Not so much.
Mostly what it’s going to do is produce intake noise and make the car effectively louder since a lot of engineering goes into the plastic twists, turns and restrictions of an intake tubing.
My more detailed response to this below made some time ago, and… my thoughts put simply, it’s never a cut and dry case whether or not it adds power, and how much power it adds, lots of factors involved, and yes the K&N kits are commonly over advertised.
https://www.ericthecarguy.com/kunena/5-Engine-Modifications/51441-theory-on-aftermarket-intakes
- You must be logged in to reply to this topic.