[Sevelyth]

Hey so as the title suggest I had a flutter sound on idle revving and everybody and their mother on this forum told me it was my stock diverter valve and to replace that and it would do the trick.


Today I had my mechanic replace it with the GFB DV+ and it did not fix it. I have no idea what else it could be. It was previously boost spiking at the end of a pull of letting off throttle. I am going home to get my tablet In order to take logs.

In short does anyone have any ideas as to what this could be?

[TheGoodTheBadTheUgly]

Originally Posted by Sevelyth

Hey so as the title suggest I had a flutter sound on idle revving and everybody and their mother on this forum told me it was my stock diverter valve and to replace that and it would do the trick.


Today I had my mechanic replace it with the GFB DV+ and it did not fix it. I have no idea what else it could be. It was previously boost spiking at the end of a pull of letting off throttle. I am going home to get my tablet In order to take logs.

In short does anyone have any ideas as to what this could be?

Ok so I have same thing as you. Replaced my DV for the GFB DV+. The flutter is still there. What is really confusing is when you use the mainspring for the DV+, it is actually said even in the given instructions that it will sound different. I recall some user telling me that the DV+ actually makes a fluttering noise naturally.

I don't see what else it could be. Check your logs to make sure that boost is on target and smooth, but other than that I will just assume that it's the new sound of my DV.

EDIT: I saw your post in MHD thread. Noticed 2 things, your corrections are not pretty and you had a boost peak of 23.2 PSI which is quite high.

[Sevelyth]

Originally Posted by TheGoodTheBadTheUgly

Ok so I have same thing as you. Replaced my DV for the GFB DV+. The flutter is still there. What is really confusing is when you use the mainspring for the DV+, it is actually said even in the given instructions that it will sound different. I recall some user telling me that the DV+ actually makes a fluttering noise naturally.

I don't see what else it could be. Check your logs to make sure that boost is on target and smooth, but other than that I will just assume that it's the new sound of my DV.

EDIT: I saw your post in MHD thread. Noticed 2 things, your corrections are not pretty and you had a boost peak of 23.2 PSI which is quite high.

Yeah I know . Do you have any idea what it could be or are we both SOL here.

[TheGoodTheBadTheUgly]

Originally Posted by Sevelyth

Yeah I know . Do you have any idea what it could be or are we both SOL here.

Honestly for now I have no clue what to tell you. That sound is hear by the cold air intake and can only be produced by the DV, I don't see what else. The DV is operated fully via electricity and not pneumatic lines which also scratchs out that theory of loose vacuum lines. I am kind of lost when it comes to this chirping.

Only thing I can tell you is to continue monitoring your car and see how well your boost meets your target boost. With stock DV, most of the time actual boost would be slightly below target while with the DV+ it is generally slightly above.

And if you could do some proper logging from gear 3 and above it would be much better. I found you AFR was a bit high, but it is probably due to the light and short third gear pull!

[Turbod]

If you still have compressor surge then it SHOULD be because you're not relieving pressure after the throttle body closes. My DV+ has a slight flutter but it is short in duration and isn't noticeable under 15 psi.

[weehe126]

Compressor surge occurs at full load/boost, not reving at idle. Are you sure you are not just hearing intake sounds?

[vespa]

If it sounds like dolphins it might be your valve cover.

[TheGoodTheBadTheUgly]

Originally Posted by vespa

If it sounds like dolphins it might be your valve cover.

More specifically the PCV or crank seals? And it would also produce the sound even if boost is low or slowing down right?

[weehe126]

Originally Posted by TheGoodTheBadTheUgly

More specifically the PCV or crank seals? And it would also produce the sound even if boost is low or slowing down right?

That sound is caused by excess crank vacuum due to bad pcv valve. It will not occur under boost. It will occur at idle if you rev the engine.

[TheGoodTheBadTheUgly]

Originally Posted by weehe126

That sound is caused by excess crank vacuum due to bad pcv valve. It will not occur under boost. It will occur at idle if you rev the engine.

Yep there you go ok. I still have that chirping sound but I am pretty sure it the GFB DV+ natural high boost noise since it only seems to occures with big boost.

Anyway I can diagnose to see if it might be PCV seal. I know that if it also does the sound whilr idling you can (I think) the oil cap test?

[weehe126]

Originally Posted by TheGoodTheBadTheUgly

Yep there you go ok. I still have that chirping sound but I am pretty sure it the GFB DV+ natural high boost noise since it only seems to occures with big boost.

Anyway I can diagnose to see if it might be PCV seal. I know that if it also does the sound whilr idling you can (I think) the oil cap test?

Oil cap is one way. More definitive is to see if the plastic nipple on top of the VC is pulling vacuum.