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Discussion Starter #1
I posted this to Phil but maybe someone else can help. My last pass at the drags a couple of weeks ago (12.01 sec 116 mph) the car came off sounding like a chaff cutter, it has reduced since then. Just like a leak out of the headers at one cylinder, increases with throttle esp at lower revs. I took off the PPE headers and all looked fine so replaced and sealed both sides of the gasket with exhaust silicone. Today I fitted the St-5 and again checked for any leaks NONE. Still the same noise, sounds like a Volkwagon beetle :-( at low revs and a bit of throttle). I checked the compression, all fine 230-237 psi.
I tested for an inlet leak by spraying some electrical contact cleaner around but had no effect. Am I missing something, PCV valve etc

noise.MOV - YouTube
 

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shay2nak
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sounds like a STi now. Reason why you hear at low rpm is because it's frequency is lower. As your revs climb, it's frequency climbs and mixes with the exhaust makes it hard to hear it.

But i don't know what that could be.
 

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Make sure all of your intake manifold bolts are intact. I had a couple of them break and you could actually see the manifold lift up off of the head while under boost. Mine sounded different but I've got the phenolic spacer on mine and it made it sound like a harmonica. Good luck with it.
 

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Nein Kinder
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Can't really tell from the video ... wild guess ... check for contaminants on a portion of the serpentine belt. I had a similar noise one time when an overflow tank dumped coolant on a length of a ribbed belt when the vehicle was stationary. On start up, I heard a rhythmic noise in time with each revolution of the belt.

Glen
 

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Discussion Starter #6
i had a header crack around the slip joint - check all your weld points.
I actually sealed the bottom of the headers and filled them with water. They leaked like hell at the four into one. Only 180 degrees of each pipe was actually welded into the collector. I got in with the welder and did the rest of the pipes then sealed with exhaust sealer. Still no joy. This noise started on my last run on the dragstrip, like I had blown something. The car runs fine but I hate the flutter noise at low revs and as I accelerate, driving me nuts.
 

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Discussion Starter #7
Can't really tell from the video ... wild guess ... check for contaminants on a portion of the serpentine belt. I had a similar noise one time when an overflow tank dumped coolant on a length of a ribbed belt when the vehicle was stationary. On start up, I heard a rhythmic noise in time with each revolution of the belt.

Glen
Thanks but the noise is not only rev related but comes with application of throttle.
 

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Discussion Starter #8
Make sure all of your intake manifold bolts are intact. I had a couple of them break and you could actually see the manifold lift up off of the head while under boost. Mine sounded different but I've got the phenolic spacer on mine and it made it sound like a harmonica. Good luck with it.
Did the car idle and perform normally as mine is doing?
 
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