Loud Whistle at WOT... any ideas?? (track video included)
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From: Louisville, KY
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Solved the problem... by replacing the exhaust. I put in a used Fabspeed Gen 1 system which solved the problem, but now I need a different exhaust. The drone is unacceptable. Thinking about going back to stock if I can find one.
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Wow glad you finally found this! I understand about the drone - solved mine with an Unobtanium but I'd suggest a little muffling in addition. were you able to figure out why it was whistling? Poor design or a crack or something else?
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No, didn't find out why. There was a loose baffle. My muffler guy cut the muffler open, welded the loose part. He then used some type of small video camera to look inside but everything else looked Ok to him. I don't think it was necessarily poor design because others would have the same problem. Probably something else came loose, we just couldn't find it.
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my dad is the OP and i'm very familiar with his car and the sound. we appreciate the feedback. i found what you're talking about...but that's def not it. (side note: props to the chick who appreciates the 996TT!!)
http://rennlist.com/forums/996-turbo...hat-noise.html
his is a very clear whistle (not a whine), and only does it under full load/WOT and doesn't come on until approximately >4k rpms.
Idle-redline in neutral: normal engine/exhaust noise
Idle-redline under load but light/moderate throttle: normal engine/exhaust noise
Idle-4k under load/WOT: normal engine/exhaust noise
4k-redline under load/WOT: insanely loud whistle which goes away once he comes off the throttle or shifts, then it comes back when over 4k and WOT
and OMG is it LOUD!!! in fact, when you're in the in-field at the track, you can hear him screaming pretty much all the way around. it's as loud as the loudest exhausts, but interestingly hasn't tripped the dB meter (maybe they don't register that high of a frequency?).
in fact, it's so loud you can even hear it when i'm following behind him, especially when he's accelerating down each straightaway. the car feels/pulls as fast and hard as my old 996TT (RIP), so we don't think it's losing power, and our mechanic doesn't seem concerned. but it's really bizarre and we get tons of ppl asking us why our car sounds like a screaming banshee...as if a canary yellow 911 turbo isn't attention-grabbing enough!
BMW M3 vs Porsche 911 Turbo at NCM Motorsports Park - YouTube
http://rennlist.com/forums/996-turbo...hat-noise.html
his is a very clear whistle (not a whine), and only does it under full load/WOT and doesn't come on until approximately >4k rpms.
Idle-redline in neutral: normal engine/exhaust noise
Idle-redline under load but light/moderate throttle: normal engine/exhaust noise
Idle-4k under load/WOT: normal engine/exhaust noise
4k-redline under load/WOT: insanely loud whistle which goes away once he comes off the throttle or shifts, then it comes back when over 4k and WOT
and OMG is it LOUD!!! in fact, when you're in the in-field at the track, you can hear him screaming pretty much all the way around. it's as loud as the loudest exhausts, but interestingly hasn't tripped the dB meter (maybe they don't register that high of a frequency?).
in fact, it's so loud you can even hear it when i'm following behind him, especially when he's accelerating down each straightaway. the car feels/pulls as fast and hard as my old 996TT (RIP), so we don't think it's losing power, and our mechanic doesn't seem concerned. but it's really bizarre and we get tons of ppl asking us why our car sounds like a screaming banshee...as if a canary yellow 911 turbo isn't attention-grabbing enough!
BMW M3 vs Porsche 911 Turbo at NCM Motorsports Park - YouTube
I have done boost leak test and checked turbos - these were fine.
Bought tuning exhaust - it removed the whistle but was too loud and I hated the sound it made under boost - quacks like a duck. Some like it (as seen form the youtube) but I hated. We, in Europe, also need to take into account that some trackdays limit loudness to 98db.
Bought another OEM exhaust, installed it and the whistle under boost also returned.
I'm out of ideas. What else should I check/look for?