BOV Flutter/Surge issue

[LandoAWD]

Normally I wouldn't post this issue, and have briefly touched on it in my ongoing Link tuning thread, but this is too odd.

Basic rundown:

-Car was fine in the spoolup/blow-off department until just recently. No changes to the intake system have been made.

-My Dodge Garage modded 1g CBV had been working like a charm...nice crisp release. Good to 25psi, but just as good at lower, part-throttle releases.

- Now, I am getting a flutter (thinking flutter, possible surge, though both are odd with no system changes) when the valve discharges. It reminds me of an old Greddy valve I had for a time on the old car. Kind of a sick tuducken sound.

-My boost seems to be coming on a touch more slowly, but FAR more violently when it finally does spool.

-I notice air leaking from the modded "nipple" at idle. This was not present before the issue began.

Thoughts?

I'm leaning towards a sticky valve and this being real flutter, but am concerned at the possibility of compressor surge (though driveability seems fine). I'm also curious as to the best method of servicing one of these suckers if it is the CBV.

 

[1bad92awd]

Not sure if you already figured out the problem or not but if I had to try and guess, I would say that the valve is leaking enough air that it takes the turbo an extra tenth of a second to actually make full boost. I suppose it is possible that the valve could be sticking, just not quite sure what would cause that to happen. Your details and information make perfect sense in that regard though. I also do know that most performance shops are able to get the parts needed to fix or rebuild the valve. You could certainly try taking it there, or maybe buying a new one depending on what they quote you at for repairs. Or maybe even if your a bit of a handyman, you could disassemble and reassemble the valve yourself. Thats really all I can think of at the moment. I hope that helps.

 

[LandoAWD]

Thanks!

I have a new valve here, but I need to get a new BOV adapter pipe as the previous owner JB-Weld'd the dang BOV to the current flange.

Ugh.

 

[Auto RS T]

I know this sounds simple, but did you check the vacuum line from the motor to the CBV?

Look for holes or tears, especially right by the nipples the line connects to. Maybe just replace the whole thing to be sure. Its cheap.

 

[LandoAWD]

I did examine it for tears and such, but no joy there. I;m really inclined to think the bov piston is sticking at this point.

Trying to find someone to fab me up a little stub pipe with a flange ATM.

 

[the_mork]

I had this same problem with my forge bov, and while I know the two function differently the fix was to take the bov apart and add fully synthetic grease around the piston seal. Again this may not work with a 1g bov but the way I was told to check is to push the valve open with your thumb and cap off the vacuum, the piston should drop a little bit but not all the way to its seat, if it does drop all the way to its seat then the seal is bad.

 

[LandoAWD]

The JB Weldedness (new word?) makes that step difficult.

 

[Freerevving]

problem sounds like a significant boost leak.... the turbo has to spin faster to create the same pressure... more velocity

 

[LandoAWD]

That would explain all but the newly leaking BOV under vacuum. Grabbing a BLTester from a friend tonight...

 

[daren_p]

I think the new unit will probably take care of your issue, my guess would be that your current BOV has a boost/vac somewhere, maybe a torn diaphragm.

 

[Freerevving]

yeah I would say that things will usually leak in both directions when they're bad enough... I've had 2 (maybe 3) 1G bov's leak under vacuum... I got rid of them

an easy way to check for leaks is to spray carb cleaner over a suspected area... it will affect the idle