A few months ago I installed a Place racing Cold air intake in my 99 Maxima to augment performance.

http://www.placeracing.com/canissanser.htm

The result is a snappier power band with a substantial increase in pull in the 4,500RPM+
range. Nice mod, it performs as advertised.

The down side however is noise. When the throttle in nailed there is a loud GROWL from the fender well, which is where the filter has been relocated. The filter exists between the car body and the plastic fender well, which prevents water and gunk from going directly into the filter. So essentially, the filter is housed in a flimsy plastic box, which increases resonant intake noise. I would like to minimize this noise.

I am looking for acoustic dampening suggestions: If I could line the flimsy plastic with some material (such as applied to the inside of speakers) it may
significantly reduce the db level.
Question is: what material, it must be flexible and bondable to plastic, also not absorb water (such as foam would do).
Any suggestions from you engineering types?

 

You might try Dynomat. Line the fender walls and the plastic liner with it. Might help a bit. Most guys like the growl a CAI makes.

 

Right, I do like the sound, just want to tame it a bit.
Thanks for the suggestion.

 

Why would you want to tame the sweet sweet sound of a CAI? Anyway, i cant see any possible way to get rid of the sound. Even if you sealed the entire fender area, there is still a hole to the engine for the sound to go through. Plus, i dont think it is the filter causing the noise. I have heard that it is the air going through the 3 inch piping and then hitting the 2.5 inch MAF. If thats true, then the noise is coming from inside the engine and there is nothing you can do about it.

DPW

 

I think he is saying the fender well is vibrating and increasing the noise. I think dynamat makes a spray on sound deadner, but spray on rubberized undercoating should work almost as well and is a lot cheaper. Check an auto parts store or the auto dept. of Wal-Mart.

As long is it is quite in normal driving, I am looking forward to the load growl under heavy throttle when I get my CAI.

 

sorry to say, but sound does not equal snappier powerband, that i think is a mistake lots of people make, there is def a small amount of loss on the high end(4500k)+ range not a noticeable increase, that is the sound ur hearing when u gun it. we dont have a variable intake so we lose a small amount on the high end, there is a great low to mid range gain, but def loss of high, ill tell u right now if u wanna maximize the power of ur CAI, drive in a graduating matter, dont stomp it down through every gear, it wont be half as fast as when u bring the gas pedal down at a constant rate therefore keeping the air/fuel mixture more balanced, opposed to flooding it with gas. plus when u do this if u havent noticed when the butter fly isnt horizontal(gas pedal floored) your car is quieter then stock, when i cruise the intake is completely dead quiet, the thing about the CAI is u can control the sound, and honestly to get the max power u dont need to stomp it at the low end of every gear, thinking that the "sound=must be faster cuz its loud"

to get back that high end get a y pipe to help it breathe better, and ull notice a quieter CAI as well,

 

i've seen this stuff at home depot once......its this sprayable foam. Apply a few amounts on the fenderwell area and see how that works, i highly doubt that it will help too much