Ram Air Intake Noise

[GTwannabe]

Hey yall, a few months back installed a ram air intake. I modified the airbox and punched a hole in the hood... got a sweet scoop. Will post pics when I get the chance (cost me $10 for a intake hose and $40 for the k&n lifetime filter, a lot cheaper than some of the CAIs ppl are buying).
Oh BTW sound is sweeet. Like a grumpy roar between 3-5k. If you listen closely there is also a nice whine when you stomp it.

Anyways sometimes when the vibe is idling I can hear a slight knocking sound. It will increase with the car rpm if the idle increases from 800 to 1000 as it sometimes does. You can also hear it while driving below 2k in the lower gears. It is not present on hard/normal acceleration, and was not present before my airbox mod. Only when you are idle or near idle and then only sometimes, usually after it is warm. The sound is coming from the airbox, not a rattle though something inside the engine is making it.

Is this just the DE-restricted vibe idle noise? Some other forums say they get similar noises when installing a CAI or RAI. Why would it come and go?

I recently got worried about the noise while reading up about oil entering intake from pcv valve and causing knocking. Doesn't sound like pre-ign or det, but I worry a lot so idk.

Any thoughts?

[beemerphile1]

You might want to add some more info like what engine, any other mods, how many miles, what year, etc.

[Water boy]

And a sound clip.

[Doug14]

indeed, pics and vid/soundclip

[GTwannabe]

I have an 07 1zz engine with 115k miles.
The engine has needed no work besides fluid/plug changes.
I was wondering if It could be the PCV valve, but not really sure.

Sorry can't upload sound.

[GTwannabe]

Oh and I have been running my air filter for 5k miles now with the noise begining with the swap. The CAI gets air through a scoop and some holes cut through the hood. Using square stock replacement K&N. The only thing between the throttle body and filter is a 3 in pipe, mass air sensor, and PCV valve hose. No additional screens. The entire upper half of the filter is directly exposed to the air (wether or not ram air gets to it in meaningful amounts is another question). This set up should be giving me a similar airflow to the round CAI people use.

[Doug14]

You could always try cleaning the maf and throttle body, and cleaning or replacing pcv valve. Not sure if original maf tube size is 2.75" or 3" but could be an issue

[Nasmfell]

I have an 07 1zz engine with 115k miles.
The engine has needed no work besides fluid/plug changes.
I was wondering if It could be the PCV valve, but not really sure.

Sorry can't upload sound.

Have you had the valve clearances checked at the 60K interval?

[Water boy]

I have an 07 1zz engine with 115k miles.
The engine has needed no work besides fluid/plug changes.
I was wondering if It could be the PCV valve, but not really sure.

Sorry can't upload sound.

Have you had the valve clearances checked at the 60K interval?

Hummmm....
Did I forget to get this done 50,000 miles ago?

I've not read too much here about people having the valves done at any mileage.

[Doug14]

It says to have them checked, but many members have not had issues. I wouldn't bother with that unless there is other top end work that needs to be done.