Berk hfc installed air surging or turbine sound?
 

So I recently installed this and it is mated to an hks hi power exhaust.

The sound I hear comes on around 4000-5000 rpm when the car is rolling.

Around the center console you can hear the high flow cats either making a surge of air almost turbo sounding. It's kinda hard to explain it but it involves air moving as far as I can tell. Revving it standing still will not replicate this.

Is this from the increased flow?

From what I know there is nothing else wrong. Doesn't sound like an exhaust leak from the outside or anything.

My only other guess would be metal vibrating. Have any of you ever heard this after a hfc install?





http://youtu.be/gCk_qJCFB1w

The video of the sound

Listen for the high pitch ringing whistle like sound

I think what you are describing it the perfectly normal 'hiss' that our vq makes.

I only hear it on deceleration at about 3k rpm though. I've been asked if my car is turbocharged at a stop light haha. I guess it almost resembles a long, drawn out blow off valve noise

Edit:

If it doesn't do it while revving, then it might be something making light contact producing a high frequency vibration noise like you said. Get under the car and check every possible area around the cats for something touching or nearly touching.

Nah I have the hiss I know what the hiss is.

This one is more like a high pitch whine

I just recently had the FI exhaust with their HFC's installed and I have the same thing. If I let off the throttle around 4 or 5k when driving and just let the engine wind down, it will make the hiss noise all the way down to about 2500 maybe. It only does it on decel. It is the VQ motor and is normal.

Are you talking about the hiss or whine?

Have you tried checking for maybe a leak?

-Frank

yup.

I went back to the corner3garage and they did a bolt check, tightened everything, checked for any vibrations by tapping the exhaust, checked for contact. Nothing is there.

it's normal :tup:

my car is stock and i have a whining sound from 3k-5k(after then road noise takes over lol) and its only under acceleration so i assume its normal

Completely normal, embrace it for it's awesomeness

Agreed, 100% normal, I thought it sounded great and it seems like the car is breathing healthier

transmission whine possibly

Nope this happens on decel and I know what that sound is.

can you make a recording?

With the HFC's, I think its the scavenging effect, correct? Creating a vacume at the front of the exhaust?