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Discussion Starter #1
Help!

When I got WOT in 2nd and 3rd, hitting it at 2.5rpm, it makes a sound like a wimpy/distant train horn. It developed suddenly after driving about a thousand miles w/ the mods on my sig.

Here's a video. I know all the normal engine/ intake sounds, but turn the bass down and listen for that weird thing. It comes in right before the engine overpowers it. It's very loud in person, and doesn't sound right. Is the engine under too much load? Is my tune too aggressive? I tightened every bolt, and checked all the hoses. This car is becoming very frustrating with what were seemingly simple bolt-ons:mad: This only happened after my 3port went on. This car responds so well powerwise to mods, but gets so bitchy, and I can't even tell what to fix!

The first pull doesn't do it in this vid, listen very carefully to the second pull!

http://www.youtube.com/watch?v=m2mQWxkoE6E&feature=youtu.be
 

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Best I could tell is that it's some kind of boost leak. I'd recommend looking at each of the intercooler piping couples very carefully to make sure none of your piping is crushed and letting air through when your boost peaks.
 

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Discussion Starter #4
Hm, maybe I overtightened the tbolts? How can I tell/what can I do if my IC pipes are a little crushed?
 

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I can't hear anything other than that VTA.
 

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I noticed a similar weird sound after I put my UICP on. Kind of like a weird whistle as the turbo is spooling. 25k miles and no problems for me.
 

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Discussion Starter #8
It's not a boost leak for sure. I induced one just to check. Idk what is wrong with it.
 

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It dosnt sound like the usual/normal UICP/LICP boost leak to me? They are usually really high pitched.

very strange sound.

Is your performance affected at all?
 

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I noticed a similar weird sound after I put my UICP on. Kind of like a weird whistle as the turbo is spooling. 25k miles and no problems for me.
that sounds like a boost leak to me.
 

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Discussion Starter #12
It lags a little, but wot is weird on my car. It sounds like something is jus being super-strained...Does anyone other than spikester even ehar it
 

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How can people not hear it?? sounds like a truck horn just before the VTA kicks in.

Its too deep for a boost leak IMO. Although... it is happening at the correct time for a boost leak.

Have you popped your engine cover to see if your Manifold is cracked/leaking?
 

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sounds kind of like my strange sound that i had. turned out to be a boost leak from the uicp. I took it off and reinstalled and that fixed the problem

here is my video for comparison
 

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Discussion Starter #15
How can people not hear it?? sounds like a truck horn just before the VTA kicks in.

Its too deep for a boost leak IMO. Although... it is happening at the correct time for a boost leak.

Have you popped your engine cover to see if your Manifold is cracked/leaking?
Thanks for listening man. Yeah guys it's not the wooshing sound, that would be an intake...

I wouldn't know what to look for, but I'll check. manifolds are headers right? I'll check if it's cracked, idk how to tell if its leaking.

And yes, it happens around peak boost.
 

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Sounds like a leak somewhere... too hard to tell if exhaust or boost coupler etc...
 

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What is sounds like to me is a leak that is causing flow turbulence leading to a harmonic vibration in an aluminum (or other thin metal) part near the point of the leak. Notice how it sounds almost like a very low note on a flute (wind instrument)? Similar principle. And it goes away when the airflow is reduced below the volume needed to create the harmonic effect.

A leak at a coupling could do this to the leading edge of a pipe, for example.

And yes, it's very noticeable in both video clips you posted. Anyone who can't hear it needs better speakers or better ears. ;)
 

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Discussion Starter #18
What is sounds like to me is a leak that is causing flow turbulence leading to a harmonic vibration in an aluminum (or other thin metal) part near the point of the leak. Notice how it sounds almost like a very low note on a flute (wind instrument)? Similar principle. And it goes away when the airflow is reduced below the volume needed to create the harmonic effect.

A leak at a coupling could do this to the leading edge of a pipe, for example.

And yes, it's very noticeable in both video clips you posted. Anyone who can't hear it needs better speakers or better ears. ;)
Thanks yacoub! I'll look into that, there's all that super-thin metal at the back of the engine bay. I'm glad you're able to hear it too, I know im not crazy lol
 

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Discussion Starter #19
The only thing is, it's only at WOT, not even 90%ish. Which makes me think it's a tune thing or something mechanical. I'm going to a mechanic and seeing my tuner next week, but thaks for he advice guys.
 

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Any updates? I've got a similar sound but after tightening all couplers, think I've narrowed it to exhaust leak.
 
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