my tial bov will open and close (but not fluttering) under part throttle acceleration while on the interstate or highway in fifth gear. its really strange and im wondering if i need a stronger spring in it. under full throttle theres usually no problem but sometimes theres something that sounds like fluttering but very very rapid fluttering, but the boost gauge is showing that its holding boost ok. when the open and closing under part throttle acceleration, there is definitely boost being lost.

 

bump?

 

bump

 

Normal part throttle with Tial. Mine does the same. Nothing to worry about as its just opening because the turbo is flowing alot of air highway crusing.

 

interesting. and what about the super high speed fluttering sound (like a machine gun chattering?) at wot?

 

That is not good as that is compressor surge. I would make sure the line going the the BOV is correct ID all the way through and make sure its not tee'd off to any other source. Spring wont matter as you're on SD.

 

what is the correct i.d.? its the same size and it goes from the bov straight to the manifold

 

you need to have a direct vacuum source for the BOV straight from the intake manifold (which you do)

here's a spring chart for the BOV


look at your vacuum reading while at idle (engine fully warm) and choose according to that reading. Mine is at 19 in/Hg so I chose the 10psi. This can all change depending on cams and stuff, so check your car's boost gauge - hopefully you have one


also, is the machine gun sound you're describing is more like a whooshing sound than a sharp sound then it might just be your wastegate operating at full boost... hard to diagnose through words on a forum, perhaps get a video with a good source?

 

http://www.youtube.com/watch?v=Cix_F...ature=youtu.be

 

Is that at WOT?

 

sounds more like the wastegate fluttering open and shut. what kind of boost control are you using?

 

grimmspeed 3 port

 

Mine does the same thing with a forge bpv. Drives me insane.

 

The grimmspeed will make that noise since its opening and closing the WG rapidly.

 

Bov is somewhat normal under partial throttle as stated, but more then likely its your 3port some make a slight whooshing noise. Id try the bov spring swap first.......how much boost r u running....