Alright, so when I bought the car I was assured the BOV was stock however I knew otherwise. Sounded fine and all that until I put an AMS cold air intake on and then the blow off valve flutters every time I let off the gas no matter what throttle I have it at. I've tried adjusting the spring and the flutter is still there. Is this normal due to the intake or is my BOV just a piece? BOV is a GFB deceptor btw after looking it up.

 

it's normal.

 

Are you getting the flutter even with boost, or just driving at part throttle? When you hear the flutter, it's not the BOV making the noise, it's light compressor surge from the BOV not opening, or opening late.

If there's fluttering even with boost and full throttle, I would check the vacuum hose and make sure one end is on the BOV nipple and the other end is hooked up to the intake manifold somewhere. If it's only at light throttle, it's normal and you'll never completely get rid of light fluttering with any valve.

 

my friends X has that problem too...i always point it out because im not used to it...but people say its normal...so i go with the flow and guess its normal...

 

Yeah, I'm not a big fan of the Evo X's e-throttle. Even when you quickly let go of the gas pedal it closes the throttle plate too slow which sometimes delays the opening of the BOV and makes the flutter for a second. On a cable throttle turbo car, you can snap the throttle shut and it'll pop the valve open instantly.

 

It'll do it no matter what, to a lesser extent if you go WOT, but it will flutter at any point. Oh well if it's normal I guess I'll just go with it

 

Like I said, check to make sure both ends of the vacuum hose are hooked up where they're supposed to be. Also, you want the spring tension to be just tight enough to hold the valve closed at idle, no tighter than that. It's not supposed to stay closed in boost or at WOT and you should hear it blow off.

Something's up...

 

I checked the vacuum line, and the connections, all was fine as far as putting it on. Guess it's back to the drawing board of adjusting the spring tomorrow, if that fails I'll take it in somewhere I guess.

 

yup, normal. I hear it a few times aswell sounds interesting.

 

If you are well under boost it should be more of a smooth woosh sound as if air is escaping. You will get the fluttering sound under partial boost.

 

https://www.evolutionm.net/forums/ev...em-my-gfb.html

also do you have a boost gauge, to make sure that bov isnt leaking?