After installing an injen intake, the stock bov (or dv) will make a "wutatata" sound or w/e after i let off the throttle on a hard 1rst or 2nd gear pull. Tried searching if it was compressor surge or flutter, bad or normal, should i get a different bov or what? Just seeing if anyone can clarify these things. Thanks

ps. car isn't tuned yet.

 

So, does your car have the black, plastic DV, or the metal DV?

 

If your car is stock and its an 05 then its the plastic bov. Most likely though its just you hear the BOV better with the intake on. I don't think I've ever heard bov flutter through the stock airbox. Heck I barely ever heard the bov through the stock box in general. I put on a cone filter and I hear the bov and its occasional flutter much more!

 

its normal... its not bad... its just the way the pressure pulses and opens the BOV. you are hearing it open like normal. it goes down like this

as you back off the throttle the throttle plate closes and creates vacuum in the intake manifold. this sucks the BOV open... but after the valve opens the pressure is different and it closes again... the vacuum increases and opens... over and over. creating that flutter sound...

if you go to a different valve with a better design like the HKS tial or turbosmart it will stay constant and release all the air at one time and have that beautiful blow off valve sound.

 

I got an hks intake and my bov will only do that at really low rpms, never at pulls or spirited driving.

 

my point exactly

 

This is right.

 

I upgraded my stock plastic toy DV to a decent stock evo 9 DV (non jdm). That was the first mod I did lol. The sounds are coming from the metal dv, and the rpms i believe reach around 4k or so when i let off wot- and it's mainly in second gear. It's been a while since i tried to duplicate it so i dont remember all the facts, but the next time i drive I'll note the specifics as to when it happens.
Thanks guys

 

just buy ofter market one if it bothers you, but u should be fine.

 

dont tell this poor kid to waste his money...

the evo 9 DV is the exact same as the JDM DV... its actually really good quality for a stock valve. mine was leak free from day one at 25psi... and when i went to 30psi it still held its own... but it does have limits...

I may not have MOD status on here but i've sat back for the past 4 yrs and read insane amounts of posts on every subject you can ask about...

i'm telling you its normal. i have an FP green with upgraded forge valve with a 25psi spring in it... and when i back off the throttle or go hard partial throttle like say 75% it will chatter when it blows off because the way the vacuum is generated in the intake manifold... if you want i will go record a couple pulls at various throttle positions and you can listen to the chatter....

 

I wouldnt mind listening for comparison

The JDM has a gold top which holds slightly more i thought. But I have heard that the stock DV is the best (crushed if needed to hold high boost).

 

oops... sorry i didnt check my sub updates... i'm a lil bit tipsy now... i will post a video tomorrow...

 

LOl tipsy on a sunday night. I just did it again and it was in 3rd gear around 4-5k. I was trying to record it but my phone was messing up.. ill try it again later

 

Its pretty normal on stock turbo's to do this it wont hurt the turbo at all. Unless the noise really bothers you I wouldn't worry about it. The symptom happens because of a resonance effect between the intake manifold and behind the pressure plate and there being just enough energy in the turbine of the turbo to boost past the cracking point of the DV. So you get a sort of wahtahtahtah noise as a result of the compressor wheel rapidly changing speeds.

You may be able to fix it by just changing where the DV gets its boost/vac source from. Personally having experienced it I never bothered haha

 

for the record... it was a monday night... not a sunday... also i made the video... but its horrible qaulity... you cant here the spool or the BOV... just my exhaust... which is retarded because my exhaust isnt that loud in person... i have to go out in a bit. i will take my digital cam this time instead of the camera phone.

as for the above... he sounds smart... but resonance is a reference to frequency and has nothing to do with a BOV. also his explanation of how the compressor and turbine are doing whatever to boost past the crack pressure to create the sound makes no sense since you even say its off throttle... if you were hitting 30psi on a stock valve and had similar sound on throttle it might make sense when using better english... the BOV would be leaking... again off throttle its caused the way i described in my first post..