well i just put my new built shep tranny in and put everything on the car incluing the STOCK bov first thendrove it and the stock bov was fluttering , i have no idea why it never did it before. so i got a adapter for the TYPE S and it is fluttering now also. i even tried adjusting the screw, an even the single spring mod still flutter. the onlything differnt from before i took the car apart is i added a ETS fmic.

please help its really anoying

thanks

 

Your stock was fluttering? Its easy to install the valve backwards. Make sure the charge is coming into the valve inlet and not the outlet

 

From my experiance usually universal aftermarket bov are not made to hold high psi. You need to get the ones made for the evos.

 

i know its not backwards. an could a little boost leak be the source of the flutter cuz it never did it on the stock one before??????

 

bump for a cure

 

Fluttering is usually assoc. with the diagphram so look for wrinkles or to see if it's torn.

 

could it be a boost leak?

 

check the manifold vacum reference line

 

all lines are connected still does it????????

 

still does it with stock bov and type s

 

turn it around and take it for a drive

 

false,
99% of the time vacuum source/line is to blame

 

flutter is normal in EVO9, I dont care what BOV is on there. Particularly stock turbo or other fast spooling turbos like the EVOGreen.

The UICP and intake manifold pressure conditions are the cause. Part throttle operation (50%) results in several more PSI pressure in the UICP than in the intake manifold. The BOV gets its signal from the intake manifold. This means that the diaghram of the BOV gets LESS pressure signal that the face of the BOV valve. There comes a point as the difference in the intake and UICP pressure result in the BOV valve lifting slightly off its seat in a cyclic manner.

This is perfectly alright, normal and nothing to be concerned with. This fluttering does absolutely nothing to the turbocharger or the performance of the engine. The boost pressure in the intake manifold does not oscillate during this phenomenon, so tuning and engine performance is not affected. Turning the stock BOV around WILL generate large pressure waves thru the intake system, not cool.

Of course this leaves you with a "Princess and the Pea" type problem; your car makes a noise that you don't like

BOOST ON!

Robert Young

 

...or has horrible driveability, as with my Greddy type RS and my Forge. OEM IX BOV FTW!

 

specially that flutter should increase after stock intake box has been removed.
i get that flutter every time i shift below 0 inhg vacuum, i guess its there all the time, but when its at 0 it gets the loudest.