Normal turbo noise?

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7,109
Location
FL, USA
While I can't hear the turbo spool on our 1.4 TSI as we could with the 1.8 TSI, there is a noise at low speed when letting off the gas. It is clearly heard in an inclosed area such as a parking garage. When you quickly press then let off the gas there is a faint whoosh noise. Is that normal? I though stock vehicles did not have a blow off valve.
 
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Location
San Antonio, TX
I thought that was compressor surge and supposed to be bad. At least that's what I was told with my turbodiesel mercedes. Course that's an older design.
 

gregk24

Thread starter
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7,109
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FL, USA
I thought that was compressor surge and supposed to be bad. At least that's what I was told with my turbodiesel mercedes. Course that's an older design.

I was under the impression that surge made the characteristic chopping noise.
 

Pew

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1,171
Location
Illinois
While I can't hear the turbo spool on our 1.4 TSI as we could with the 1.8 TSI, there is a noise at low speed when letting off the gas. It is clearly heard in an inclosed area such as a parking garage. When you quickly press then let off the gas there is a faint whoosh noise. Is that normal? I though stock vehicles did not have a blow off valve.

That's normal, all turbos have BOV/BPVs.
 

Astro14

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Virginia Beach
All my turbo cars have a diverter valve - AKA blow off valve - AKA compression bypass valve. The faint whoosh sound that you're hearing when you lift off the throttle would be that valve. IF it gets too noisy, then it's likely in need of replacement, but at your car's age, it should still be OK.
 
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1,393
Location
Richmond, VA area
While I can't hear the turbo spool on our 1.4 TSI as we could with the 1.8 TSI, there is a noise at low speed when letting off the gas. It is clearly heard in an inclosed area such as a parking garage. When you quickly press then let off the gas there is a faint whoosh noise. Is that normal? I though stock vehicles did not have a blow off valve.
Yes, all turbos have to release pressure when you build boost and then shut the door so to say (throttle body closed). They have a diverter valve which is just a BOV that recirculates the charge pressure/air to the intake before the turbo vs. venting to atmosphere. The closed intake masks most of this nose but you will hear it in some circumstances, especially a closed area like a parking garage.
 
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3,360
Location
Chicagoland
I thought that was compressor surge and supposed to be bad. At least that's what I was told with my turbodiesel mercedes. Course that's an older design.
Not sure for diesels, but for gas engines it depends when it happens. If you’re at WOT then let off and hear it you’re okay, if you’re at WOT and hearing it bad things are going to happen. Compressor surge/flutter gives you that “STUTUTUTU” noise, a single whoosh or hiss is is a recirculation or blow off valve.
 
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