I have a 2004 with 10,000+ miles on her. I was checking out K & N air filters on a web site. I opened the filter box for the 1st time to see that the Honda filter looks like a K & N filter. I also observed the plastic intake snout is small in opening area compared to the air filter surface area. That's odd. For what ever the reason I went for a little drive without replacing the lid to see if more opening would add to performance. Maybe, I guess, but boy did the engine sound better!! It had a much deeper sound on hard acceleration. What's the deal with the box and engine sound? What's the lid for with a filter that big and a snout opening that small? What do you guys think about this?

 

keep it on. taking the lid off lets in more hot air which decreases performance. search for gutted air box if you want more performance from oem intake.

 

btw, you should hear the intake with no lid AND a vented hood!

 

If you want more sound, take a piece of cardboard and some tape and seal off the resonator chamber that's on the right side of the stock airbox.

 

What do you mean by gutted air box? My box is empty except for the Honda filter.

 

Stock airboxes have a little plastic divider in them to "box" in the filter. Some people like to cut that away, hence gutting the airbox. If you don't have a divider the previous owner must have done it for you.

Personally I don't see a point in it since the air intake has a 90 degree elbow to direct the airflow directly to the filter, but you can do what you want.

 

Thanks guys for the help. I'll try your suggestions in the morning.

 

CAI was the way I went. Though the K&N FIPK is pretty popular around here.

 

I don't believe this, and there are plenty of intake applications in cars and S2000s that bely this. Also, having driven for years with the airbox lid off, I can say that my S is no slower or boggier than any S with the airbox lid on. Once the car is moving, there's plenty of cool air rushing into the engine bay - heat only builds up while idling, and that happens with the lid on as well as off due to the design of the intake.

Honda designed the airbox to muffle the intake sound. That is why there is a resonator chamber and why the box plastic is so thick. If you have a K&N intake now and like the sound with the lid off, then stick with it - there's no reason to drop $300 on an intake that does the exact same thing, like K&N's FIPK, which if you really look at it, has plenty of gaps to let air in from the engine bay.