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Old 08-22-2012, 05:19 PM   #14
blanko
Registered User
 
Join Date: Sep 2011
Location: El Dorado Hills
Posts: 37
My Ride: 04 M3 SMG
Good news, mine is fixed. No more whistle whatsoever! Mark from Marco Muffler in Sacramento was able to figure it out and have it fixed in an hour or so. The problem is in the tips. The single pipes that split out into the Y-tips had too small of an inner diameter for the amount of exhaust flowing through it at high RPM.

Thankfully it didn't have to get hacked into pieces to get rid of the whistle. He just used a carbide grinding bit to grind down the lip that was created when welding the tips on. This increased the inner diameter of the each pipe right before the Y split, allowing for better flow of exhaust gas at high RPM. Low and behold the whistle is completely gone.

For those of you who don't have this problem, you guys got lucky and got one that didn't have the little extra bit of restriction in the pipe right before the tips. For those of you that do have this problem, it can be resolved
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