TT whistling after car shut down

alanforn

On normal start up driving home from work car shuts down quietly. Lately when I get home I shut the car down go into house to disarm house alarm, open the garage door restart the car, pull it in and shutdown. When I do this after turning car off there is A high pitched whine sound from exhaust that continues for a few seconds then winds down, literally sounds like the turbo is still spinning until depressurized. So basically this happens as quick as I start, pull in garage then shutdown so cars probably running for 30 seconds or so. I could always just keep the car running when I get home but wonder if this is normal or is something sticking (BOV)? Today I let the car cool down for an hour or so then pulled into garage, same thing happens.
??????

SouthArk370Z

Subbed to see what others come up with.

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Spooler

Sounds like the turbo's are winding down. They will do this. It is normal. Just make sure you let it idle and get the EGT's down to around 400 deg max before shutting down. This will help prevent coaking.

Kris9884

I mean, maybe you're trying to explain a separate noise but its completely normal for the turbo to down spool for a few seconds afterwards. Just proof you have some free spinning turbos, this is a good thing if nothing else.

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JSur

I've had this issue before too. Never found the root cause because it worked itself out but it's definitely something depressurizing after you turn it off. After I'd shut it down it would make that whine anywhere from 10 seconds to a minute after. Strangest thing.


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alanforn

Yes, its not a spinning down noise, more like letting air out of a baloon tweaking the neck creating that eeeeooooooo sound. Getting signed up you tube so I can post a video.

JSur

Exactly. Real high pitched. What kit do you have?


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TerribleONE

Do you have a electronic boost controller?

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alanforn

AAM with Borg Warner

alanforn

No, saving coin for controller

SouthArk370Z

Since it doesn't seem to be spool down noise, it's probably an air leak. BOV not sealing?

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alanforn

Thats what I was wondering, may pull the bumper and check out. Know I've read some info on cleaning and lubing, buddy has turbo and says can adjust spring tension but not sure what method to use, will research more.

JSur

Borgwarner turbos on this kit don't have BOV. Unless he put one on


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Jayhovah

Interesting. Haven't noticed this sound on mine, but ill be more vigilant now.

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Rid3_FaM0uS

lololll there are no BoV on the AAM kit so don't waste your time there. I would definitely suggest doing some sort of vacuum/boost leak smoke test on the car though. curious do you have all of your PCV hooked up on the car? I'm assuming AAM did the install so ill venture to say yes. If it happens for as long as a minute its definitely not a turbo spooling down. exhaust gases will bring the turbo to a halt rather immediately after shutting the engine down. there is little to no "free spool" happening beyond this point. I am curious, however, if your PCV check valves could be installed backwards causing a slow "release" of the crank case pressures after the engine has stopped cranking.

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