Turbo Flutter/slow BOV

[Roadrunner]

I just had a thought - have you replaced the OEM air box?

Just a little...
Turbosmart reckon its the all metal intake acting like a trumpet amplifying the sound. I drilled and tapped the rear of the intake manifold last night with a 5/16 barb with that size hose running all the way to the BPV. Will give it a test run tomorrow and see if there's any difference.

[lambertius]

Rightyo, so on the standard filter box there is a little pipe to nowhere. That is a helmholtz resonator and it knocks out a lot of resonant tones from the engine. The SP doesn't have one, and it also has a short run to the turbo inlet.

I would hazard to guess that you are indeed amplifying the sound of the turbo with your airbox.

[Roadrunner]

Yep I believe that's it. It's just annoying. Would much prefer the typical Psst noise but the chopped air noise is just so much louder at anything over 5psi.

[Techno]

Hi there,
Can you post a picture of the plumbing set-up at the BOV .... If you are using the the bottom port for inflow then the pressure can lift the seal depending on the BOV spring rating. New turbo puts out more pressure .... so you may have the seal lifting early.

I prefer to use the side port for the inlet as the pressure effectively pushes the seal down and the diaphram up equally.. so no seal lifing

You might like to know that Mazda SPs were plumbed with the side port as the inlet port ... see picture from Mazda site here


Regards
Rob

[Roadrunner]

Hi Rob, the Turbosmart Compact valve is a pressure differential valve and must be installed the way it is in the photos on the first post of this thread.
It’s been verified to open instantly when pressure drops on the signal side. Holding pressure under boost isn’t the issue.
Turbosmart have advised me that everything I have is connected correctly and it’s likely the larger intercooler and all metal intake amplifying the choochoo noise.
One day I might be bothered enough to put the BOV on the hot side of the intercooler to test.