Sudden Turbo Flutter?

Freddy Turbina

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Was driving earlier today, and noticed after a bit that my the turbo had a noticeable flutter after letting off the gas after hearing the turbo spool.

Has anyone else noticed anything like this? Earlier today I had given it significant gas, heard the turbo spool, and then nothing after letting off the gas. Now, after any time the turbo spools I hear a “garbling” sound that sounds similar turbo flutter.
 

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I entertain myself at low speed driving by pressing gas briefly and listening to the flutter. It's kinda fun.
 

Osco

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Never paid much attention after the novelty wore off but I do think the flutter adds to the cool factor.
Prolly sounds a little trick if your standing by the road and I flutter by,,
 

Meanderthal

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It sounds like what is being described is not “turbo flutter” but the diverter valve (or blow-off valve) releasing the pressure that has been built by the turbo. That is a normal sound on a turbo engine but may be more/less prevalent depending on a few factors. I’m not sure if the diverter valve is under the engine cover, but that could be one of the factors. Hood insulation could also be a factor.

They all make an intermittent “whistling” sound to some extent that I have experienced. I don’t think that any OEMs use a blow-off valve any longer because of emission regulations and probably sound specs. The difference between the 2 is that a diverter valve feeds back into the intake piping while a blow-off sends it out into the atmosphere.
 
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Freddy Turbina

Freddy Turbina

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It sounds like what is being described is not “turbo flutter” but the diverter valve (or blow-off valve) releasing the pressure that has been built by the turbo. That is a normal sound on a turbo engine but may be more/less prevalent depending on a few factors. I’m not sure if the diverter valve is under the engine cover, but that could be one of the factors. Hood insulation could also be a factor.

They all make an intermittent “whistling” sound to some extent that I have experienced. I don’t think that any OEMs use a blow-off valve any longer because of emission regulations and probably sound specs. The difference between the 2 is that a diverter valve feeds back into the intake piping while a blow-off sends it out into the atmosphere.
This is my first vehicle with a turbo, so the noises are all new to me as the driver- appreciate the information!

Tried to get a video of the sound this morning, and nothing happened! Spent the whole day on the beach yesterday (including getting a little stuck up a sand hill and trying to get out) so I am wondering how much engine temp/conditions might matter to hear the sound. I suppose an overnight cooldown might reset whatever my gauntlet of driving did to it yesterday.

Might try to get a video of the sound sometime in the future when it happens again just so others have a reference noise.

Thanks again!
 

Elegance

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Coming from a little Hyundai Accent, I'm learning a lot about the unique turbo noises and tendencies as well. The flutter scared me to death at first, thought my whole engine was about to die. I've learned to embrace the sounds. 🙂
 

Meanderthal

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This is my first vehicle with a turbo, so the noises are all new to me as the driver- appreciate the information!

Tried to get a video of the sound this morning, and nothing happened! Spent the whole day on the beach yesterday (including getting a little stuck up a sand hill and trying to get out) so I am wondering how much engine temp/conditions might matter to hear the sound. I suppose an overnight cooldown might reset whatever my gauntlet of driving did to it yesterday.

Might try to get a video of the sound sometime in the future when it happens again just so others have a reference noise.

Thanks again!
You will need to get the engine under load and with some rpm to develop some turbo pressure. When you let off the throttle, that pressure needs to be released or it feeds back against the turbo and bad things start to happen to the turbo. Not immediate turbo failure but more like a high wear sort of thing (not really wear but I’m trying to simplify it).

Being on the beach and even getting stuck most likely did not get enough load/rpm to develop the turbo pressure that would need to be released by the diverter valve. A hard acceleration from a stop will develop the highest pressure and if you suddenly let off the throttle the diverter will being doing its primary job. If you hear the noise when you do that, it is a normal noise.

I doubt that the BS will ever have turbo flutter. It happens more on manual transmission cars when the driver tries to accelerate without a needed downshift. That noise could be described similarly to the diverter sound but the frequency of the sound is much lower and usually the volume as well.
 

Meanderthal

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