Mijae007

I just wanted to share an observation I've made with my car that may help others in trying to reduce or eliminate any exhaust drone one might have. Ever since going turbo I've had a pretty bad resonance issue at 3k rpm. All my loose coins and anything in my cupholder would rattle at that rpm. From research, it seems everyone tries tackling this issue by altering their exhaust system; by adding resonators and such. I've found that altering my intake side resulted in a positive change.

I've had 3 different intake filter setups and surprisingly enough, all had a drastic effect on drone.

I am straight pipe 3" all the way thru with no cat and no resonator. All my exhaust piping are free of rubbing and vibration free. On my setups with 1. aem dryflow filter and 2. no filter with metal screen, there was drone right at 3k rpm; worse on a cold startup drive.

I recently added an hks style foam filter and surprisingly my drone has been eliminated completely, both on cold startup and normal conditions. It's so much more pleasant to drive.

So if anybody is having trouble even after having tried adjusting their exhaust systems, try different air filters on to see if it will help!

EDIT:
think i spoke too soon. on cold start up this morning i could notice the drone at 3k rpm, its just a lot less than what it used to be. I can feel the increased vibration caused by the drone but its not like it used to be rattling all my coins and stuff.

Charper732

Just a warning, that filter WILL disintegrate over time. I had issues with the plastic frame getting brittle and breaking aswell. If you do run it, I'd suggest you don't run the filter straight on the turbo inlet as im sure the heat soaking after the car is shut off is what led to the failure of mine

EOE

CT-Engineering foam filter made no difference on my SC setup, if anything the recirculation BOV/BPV is a lot louder, sounds almost as if I'm running part of it to atmosphere. Foam sounds like a bad sound insulator to me so I am not sure how it cured drone in your case.

Mijae007

good call okok. Ill keep an eye out