I have a 06 mr and I'm getting pretty bad flutter but only in low rpm and under low load. For example if I just start pressing the gas and get it to about 1psi or around there then it will flutter pretty bad. If I let boost build or press the gas pedal harder its fine. Check vaccuum line and did boost leak test found nothing. Any other ideas? I had a Greddy type s and diaphragm was bad so put factory one on and it's about the same. It also has injen uicp and licp. Thanks for your time.

 

Mine is like that. Stock 9 bov

 

So it's normal?

 

I'm not a mechanic but from my search, i understood it is normal for that light throttle.

 

Anyone else?

 

mine does that too

 

mine did it once it got old and worn out. Didn't ever do it that i remembered the first couple years. Eventually it got constant under the light load, light throttle release. I could avoid it with sharply removing the throttle to allow it to vent all pressure.

Never fixed it, I just built a race motor instead

 

Have had the same issue and it gets worse if you crush the diverter. I had some success in regards to the this by adjusting a table in Ecuflash. You can try this if you have the cables to hook into your OBD-2 connection with you computer. Not sure if changing this setting has any adverse effects but I haven't noticed any, maybe someone with more knowledge on the subject can chime in. Anyway the setting I changed was -

"WGDC = 100% under this load" from 200 to 150


Like I said not sure if this could cause other issues, like a loss of power, but this change seems to have removed most, if not all, of my partial throttle flutter.
Cheers

 

Its called compressor surge. look it up.

 

No compressor surge is very different and is caused by pressure fluctuations within the turbo itself. What the op is experiencing,IMO, is caused by the diverter valve opening and closing rapidly under partial boost and throttle positions. Not sure what is causing this but I find it is most evident when in high gears (5th and 6th) and low rpm with low to mid throttle position. I've have had compressor surge too and it sounds and feels very different, more violent with a longer cycle between surges. In my experience compressor surge is experienced more in high gears, again 5th and 6th, but at wot. There are a few good videos on YouTube of motors suffering compressor surge on dynos and these give a good idea of the difference between bov flutter and compressor surge.

 

not in my case, and i don't think the OP's either. Surge it different

 

The stock valve has some slight flutter to it, I believe changing pipes and such may also get it to come out more then 100% stock. That has been my experience.

Surge usually takes more then 1psi to happen, but the stock turbo can certainly give you turbo surge too.

 

Incorrect! Surge only feels violent when there is a lot of air moving through the turbo. More air=more turbulent force. If the shaft rpm is low when the flow becomes turbulent then it makes a fluttering sound . This is because flow reverses direction and applies force to the spinning turbine when the valve is closed when it should be open. The bypass valve is controlled by engine vacuum. Engine vacuum doesn't make wide swings from positive to negative. Therefore there's no way the valve itself can 'flutter' open/ closed. Seriously, where do people get these ideas?

 

It's compressor surge guaranteed, and i bet if you check ur bov it is backwards. There was an article i found awhile ago about the bov bein put in backwards from the factory cuz it can basically go in either way, the only thing about having it backwards is, it causes compressor surge and will eventually eff the turbo which i found out the hard way. U need to check the bov and make sure the top of it is pointing TOWARDS the radiator and not straight up into the sky.

 

It isn't surge. My IX dv does this as well under light throttle if I let up quickly, right on the edge of vacuum/boost.