Thanks. I appreciate all the replies. I have put my stock BOV back on. It does leak a bit but I tried all the above minus replacing the vacuum line. I thought about that. I also took apart the BOV to see if the spring was bad or broken. All looked ok. I did keep the pre load spring in there. Seemed when I had it loose (the adjustment screw) made things worse. Its my daily and I drive about 150 miles a day so will see maybe next weekend I can try a few more things.

As far as mounting I don't think I can mount it like that unless I don't recirc the BOV. I would have to VTA. Worried I would run super rich...

 

I have absolutely zero part throttle flutter, mine opens every time I lift the throttle, anywhere from -5 vacuum all the way up to full boost. Mine is also mounted vertically, pretty much exactly like Thedru.

Thedru, the breather hose from the head would not cause the BOV to flutter, mine is venting as well.

Are you sure the preload is at it's lowest? When I plugged both A and B ports on mine I didn't need to change anything else to have flutter-free operation.

 

For the preload I screwed it all the way down.. So you can't see any of the threads.. Just the nut.. When I had it all the way out seemed to be worse..

 

I imagine that's too much preload. Here's how mine looks.

 

Thanks raptord.. I will mimic what you have and install and see what happens.. I don't think much will change. IDK just don't get it.

How much boost are you running?

 

22 psi on my track map and 24 on my street map.

EDIT: This is on stock turbo

 

got it. Just odd. Our mods are really similar.. intake is different and I have an UICP.. But for the most part pretty much the same. Your cams are a bit more aggressive than mine. I run 25psi and have a 6 speed.. But i can't even go up a hill with out that thing fluttering.... And the car BUCKS.. So I am not sure if they spring that came with it is to light or what but I will back out the pre load spring a bit. And try again i guess.

Wonder if my MBC plays a part in it..

 

I just had an idea - Are you tuned on Tephra V7? If so, do you have "WGDC = 100% under x load" enabled? What value does it have?

 

I am not.. I would have to look at my tune to see what my WGDC is. What should it be? I am on my Macbook so don't have my tune on here..

 

If you're not on Tephra then nevermind, that won't be the problem. With Tephra that table forces WGDC to stay at 100% until a certain load is reached to get the turbo spooled as quickly as possible. Under partial throttle though it caused my car to buck quite badly if I just barely reached that load.

 

I will double check. My buddy does most of my tuning. I can turn a wrench but not great at the tuning part. You may be onto something cause even on my stock BOV it will flutter alot.

 

My synapse fluttered only on part throttle, low rpms, and in top gear. After when I got tuned the flutter went away. Since then I removed the pre-load spring and there was no change.

 

Have you been tuned yet with this BOV? I noticed after I was tuned the flutterer was allot less noticable. Since the Synchronic is very fast responding it may not work according to your current tune. I have noticed that each engine that uses one racts a bit different as well. I run 30 PSI boost on mine and I am tuned with a GM 3-port boost solenoid.

 

Was not tuned on this BOV. I may try to install and do some logs just need to find time.

 

I don't see how or why switching from one recirc'ed bov to another recirc'ed bov would require a retune.