Engine Air Filter

[ctrcbob]

Seeing as how I'm the type of person who likes to see how things work, I decided to see how hard it is to change out the engine Air Filter.

Very Easy!

While I had the filter out, I looked inside the filter box and could not see where the air enters the filter box. Then I noticed what looks like a "trap door" inside the filter box. I pulled the trap door up, and when I let go, it sprang back to the closed position. I don't know what opens this trap door when driving, if it is engine vacuum, or what. Good idea though as it keeps the mice out of the filter box when the car is just sitting.

 

[ctrcbob]

Seeing as how I'm the type of person who likes to see how things work, I decided to see how hard it is to change out the engine Air Filter.

Very Easy!

While I had the filter out, I looked inside the filter box and could not see where the air enters the filter box. Then I noticed what looks like a "trap door" inside the filter box. I pulled the trap door up, and when I let go, it sprang back to the closed position. I don't know what opens this trap door when driving, if it is engine vacuum, or what. Good idea though as it keeps the mice out of the filter box when the car is just sitting.

While at my doctors office this morning, I picked up his copy of the May 2009 issue of Road and Track where they have a test of the 2009 Genesis 4.6 V8.
It mentions that this car has "a two stage variable induction system" and continuously variable valve timing. I know what continuously variable valve timing is, but I wonder if the Two Stage Variable Induction System has anything to do with the little trap door in the air filter box.

If not, what is it?

 

[MarkF001]

I believe it varies the volume of the intake track, for low end tork, or high end power.

 

[TJPark01]

What do you guys think about those K&N air filters? I remember changing the filter box for my 1991 Nissan Maxima, thinking I would get some performance benefit. Mostly what I got was a sucking noise like a vacuum and crappier gas mileage. When it comes to oil/air/gas filters I normally default to using the OEM, for the most part. Would like to hear about other peoples' experience with these aftermarket air filters.