Weird BOV sound

I got my turbo installed and running, my only question now is that my HKS SSQV makes a fluttering sound when shifting under low boost and sometimes with high boost. Should I tighten or loosen the BOV or is this normal?

where is your setting now. I have mine with about 4 threads showing between the bolt and the adjustment nut and it does sound like that sometimes under low boost when I let off the gas slowly. I have the same bov as u and it makes several different sounds depending on boost levels and how fast you shift.

I got my turbo installed and running, my only question now is that my HKS SSQV makes a fluttering sound when shifting under low boost and sometimes with high boost. Should I tighten or loosen the BOV or is this normal?


That is the sound that a car makes when the BOV is not working or does not have one. It is called compressor surge. As you know, when you let off the gas, it closes the throttle plates, but the turbo is still trying to cram air into the engine. Well when this happens the air has only one way to flow, and that is backwards. compressor surge is reall hard on a small turbo with floating bearings. However, a large shaft turbo or a ball bearing turbo is does not matter.

Get your sneeze valve set right and it won't happen.

How do I go about doing that? Do you mean adjust the BOV?

if you are actually getting compressor surge make sure you have the BOV connected to a good vacuum source after the throttle body. If your hose it connected right then your BOV might actaully be adjusted too tight. To loosen it up you need a 10mm open end wrench, there is a nut that locks the adjusting bolt into place. Once you loosen this up you can back the bolt out a few turns then make sure you retighten the locking nut. The hks ssq BOV actually makes several different sounds and some of them do kind of make a fluttering sound from the floating plate in the air valve so if the sound continues it might be normal.

I have the BOV connected to the brake booster by itself and I just finished loosening it up a bit. It kind of helped but it still made that fluttering sound. I'll admit that depending on how I shift it does make a different sound so maybe that's just the way the BOV is.