Help Me Identify This Sound
 

I don't have a video of it (yet - I hope one isn't necesarry) but hopefully describing it will lead someone to the answer. I just got finished installing Berk HFC's this past weekend and previously I had put in Stillen G3's the week before. At wide open throttle I start to hear a high pitched scream (almost like a whistle) as the car heads into the 4k+ RPM range. I don't remember hearing that when it was just the Stillen G3's installed but it is definitely there now that the Berk's are in place. It doesn't seem to happen when the car is just sitting and rev'ing but only under true acceleration. Any thoughts on what this might be and whether or not it is just a normal behavior of this particular combination? I have the HKS Hi-Power exhaust as well. I did dismantle the G3's to install the Berk's - is there an easy way to detect small leaks on the intakes or cats?

Thanks!

What you're hearing is the vacuum of air rushing through the filters/intake piping into the engine. Now that the entire breathing system is more open, a lot more air is flowing. You could hear this more prominiently through an SRI but even with the Stillens, now paired with your HFCs and CBE, is now more pronounced. Nothing wrong with it. :tup: Just means you need boost! :tup:

How does one acquire boost? :)

I wonder if the UpRev tune will make this more prominent in the low RPM range as well - anyone want to take a guess at what my before and after Dyno's will look like given my setup? Only performance mods so far are Stillen G3's, Berk HFC's, and HKS Hi-Power Titanium Exhaust.

Boost would be from a Forced Induction setup, either Twin Turbo or SuperCharger

As for possible Dyno numbers, the best way to answer this would be get a dyno run prior to the tune, then get one after the tune on the same dyno.

hrmm you sure?

the stillens make a sound up top but its not a whistle.

Its 1 of 3 things...

1. Signature Stillen Sound
2. Vacuum Whistile
3. A Leak somewhere in a Vacuum Line

Sounds like a bad vac leak.

While the car is running, spray some carb cleaner under the hood. When the idle dramatically changes, you've found the leak.

Also if you could take a recording of the sound that might better help distinguish the culprit...

Maybe a whistle was the wrong phrase - it sounds more like a high speed turbine. If it were a vacuum leak wouldn't I hear it all times. I suppose I could swap the intakes back to stock temporarily. Not sure I want to start spraying carb cleaner around under my hood just yet. :)

I'll see if I can get a video of it so we can narrow it down.

Something else to consider... Where exactly is the sound coming from?

The Engine Bay? or Under the Car??

Perhaps theres an exhaust leak somewhere? Blown gasket, bolt not all the way tightened?

Apologies guys but time has slipped away from me and I leave for Mumbai, India tomorrow morning. Top of my priority list when I return is to get a video up so I can get this resolved. Thanks for all the tips so far! :tup:

Ok, just back from India and taped these today:

YouTube Link

I was honestly having a hard time pinpointing just where the sound was coming from. Any thoughts on what that sound might be?

Thanks!

I thought I heard metal on metal -- something hitting or rubbing?

Now that you bring it up, I can almost hear the metal on metal as well. I know when I installed the HFC's that I had to remove the upper part of the intakes and during re-install I might have tweaked the lower pieces with the front bumper completely in place. So, I can't really tell what went on there. I think I'll yank the front bumper off again and see if that is what the issue is here. I can't see metal on metal being an issue near the HFC's but knowing how tight it is under the fascia I hope that is where I'm going to find the culprit.

Thanks for the tip and I'll keep you guys informed of what I find.

When you change your HFC, did the engine warning light come on? I'm planning to change mine but i don't want the warning light to come on.