[b1aze]

I just installed a Synapse BOV last weekend and after i finally got the coupler to stay on the throttle body, it held boost just fine. The sound is nice and noticeable but not annoying (yet). My wife does think it sounds like somethings wrong with the car or its sneezing however.

Running Cobb STG1+FMIC Aggressive LT ~18psi peak
6MT
ETS FMIC
OEM intake box and filter

Occasionally, under WOT at varying RPMs and gears, when i let off the throttle, the BOV sounds like it vents, closes and vents again. Im sure thats exactly whats happening and i can actually feel it in the car and i would imagine it cant be good for the turbine wheels. I dont think its necessarily surge, but it definately there.

If i had to speculate, i would imagine its the valve opening, and with pressure still in the chargepipe, closing again because it either bounced back or the charge pressure just overpowers the vacuum line force. I would imagine adjusting the spring force via the adjuster in the back could fix it, but Synapse says not to touch it...

Is there a solution to this? Anyone else experience similar things?

[mrbillytalent]

I have no helpful input at all however...

Originally Posted by b1aze

My wife does think it sounds like somethings wrong with the car or its sneezing however.

My gf says the same thing. Makes me cry everytime

[BoostedE90]

Normal for shifts over ~5k.

http://www.e90post.com/forums/showthread.php?t=806529

Originally Posted by b1aze

My wife does think it sounds like somethings wrong with the car or its sneezing however.

Haha! My girlfriend always asks me why I paid money for my car to make a funny noise.

[Chris_506]

Originally Posted by b1aze

I just installed a Synapse BOV last weekend and after i finally got the coupler to stay on the throttle body, it held boost just fine. The sound is nice and noticeable but not annoying (yet). My wife does think it sounds like somethings wrong with the car or its sneezing however.

Running Cobb STG1+FMIC Aggressive LT ~18psi peak
6MT
ETS FMIC
OEM intake box and filter

Occasionally, under WOT at varying RPMs and gears, when i let off the throttle, the BOV sounds like it vents, closes and vents again. Im sure thats exactly whats happening and i can actually feel it in the car and i would imagine it cant be good for the turbine wheels. I dont think its necessarily surge, but it definately there.

If i had to speculate, i would imagine its the valve opening, and with pressure still in the chargepipe, closing again because it either bounced back or the charge pressure just overpowers the vacuum line force. I would imagine adjusting the spring force via the adjuster in the back could fix it, but Synapse says not to touch it...

Is there a solution to this? Anyone else experience similar things?

Its more then likely a bogfix feature on your tune to retain some boost while shifting. If it only happens over 5k rpms it is normal. it usually only does it while drivinf and under load so the easiest way to test is to rev it up on neutral, if it releases the boost on neutral above 5k rpm you're good.

[b1aze]

See it happens lower than 5k rpm also. I did it today in 6th gear at like 3500rpm after WOT.

[Chris_506]

Have you double checked all your vacuum lines, are they installed correctly and none of them unplugged? Mainly the one that connects the bov to the manifold on the manifold side?

[b1aze]

Originally Posted by SCSRe92

Have you double checked all your vacuum lines, are they installed correctly and none of them unplugged? Mainly the one that connects the bov to the manifold on the manifold side?

Everything is plumbed correctly. I have not checked the manifold side but the valve actuates fine usually. Most of the time it blows off normally in one long release but occasionally it does not. I'm trying to figure out if any specific conditions are causing this or if its just random.

[Sparky68]

Do these ones have adjusstable spring pressures, ie you can set it on the BOV ? Sure i read that somewhere but cant remember where.

[b1aze]

Yes but per the instructions from Synapse, they advise not adjusting it. I have an email into their support line but they take FOREVER to respond if they even do...

[robc1976]

Originally Posted by b1aze

Yes but per the instructions from Synapse, they advise not adjusting it. I have an email into their support line but they take FOREVER to respond if they even do...

my synapse never did this that I know of.

[b1aze]

It seems to happen more in a higher gear, low rpm high load situations. ill try to get a video of it.

[135Pats]

Originally Posted by b1aze

It seems to happen more in a higher gear, low rpm high load situations. ill try to get a video of it.

How much load are we talkin? The motor's gunna run like crap if youre giving heavy load in 6th. FWIW i dont hear my synapse do that, next time im wot ill confirm.