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acceleration jerking with bov

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Old Feb 25, 2011, 04:58 AM
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acceleration jerking with bov

wanted to get some input on this, here's my current mods:

full tbe
nisei intake pipe/k&n filter
nisei 1 pc uicp
ams fmic
3 port bc
synapse bov (non-evo specific, the one with the side port)
custom tune

here's the thing, with the synapse side port hooked up to the 3port (T'd going to the intake), the car jerks on initial acceleration usually on 2nd & 3rd gear...kinda like the bov opens in the middle of acceleration, thus causing the car to jerk. so i decided to plug the side port on the synaypse bov, given my car has no down time since it's a daily driver & i don't have my stock bov anymore so i don't have the luxury of sending it back to synapse and having it retrofitted to be evo specific. after doing this, the car seem to accelerate A LOT smoother, although it seems i don't hit boost as high either. the car doesn't feel slower though...it just doesn't hit boost quicker and higher.

would a re-tune fix my boost issue? it doesn't look like i have any boost leaks...and what are the consequences of me plugging that side port on the synapse bov? any info would be greatly appreciated..thanks!

Last edited by reggiesd; Feb 25, 2011 at 05:02 AM.
Old Feb 25, 2011, 05:33 AM
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give it a couple weeks. sometimes the springs need to get broken in a little before they smooth out
Old Feb 25, 2011, 06:21 AM
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I've had it for some time now though
Old Feb 27, 2011, 05:38 PM
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I am kind of having this same problem, mine is happening when i go full throttle immediately, if you ease into your throttle does it have a nice gradual pull without the jerking?
Old Feb 28, 2011, 03:49 PM
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i get this too. It ALWAYS happens in 5th gear at 60ish mph @ about 3k RPM coming off the throttle or holding steady at maybe 20%. Happens in other gears with similar ratios (mph/rpm/throttle). I just think it's because the turbo is trying to spool without enough air, right?
Old Feb 28, 2011, 04:01 PM
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Originally Posted by TruSlide
i get this too. It ALWAYS happens in 5th gear at 60ish mph @ about 3k RPM coming off the throttle or holding steady at maybe 20%. Happens in other gears with similar ratios (mph/rpm/throttle). I just think it's because the turbo is trying to spool without enough air, right?
I get this too, usually only in 5th, below 3k RPM. I always assumed it was because there isnt enough PSI to open the BOV firmly all the way, so it kinda just sputters a little. Jerks the car around too, kinda annoying lol. Was worried the first time it happened, but it seems lots of people have similar issues.

Edit: And i still have the stock valve, so I assume any aftermarket BOVs will have stiffer springs to handle higher boost, so the problem is probably worse with them...
Old Feb 28, 2011, 04:11 PM
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Actually... with my BOV set all the way to stiff it seems to be alright. If I don't let off the throttle 100% instead of atmosphere release it just flutters and I get no sputter. But that acceleration jerking is annoying. I'm hoping once I get the parts to let it breath more it will go away or get better.
Old Feb 28, 2011, 04:41 PM
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Originally Posted by TruSlide
Actually... with my BOV set all the way to stiff it seems to be alright. If I don't let off the throttle 100% instead of atmosphere release it just flutters and I get no sputter. But that acceleration jerking is annoying. I'm hoping once I get the parts to let it breath more it will go away or get better.
Odd...with the stock BOV?
Old Feb 28, 2011, 08:03 PM
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yeh you need to either set to full stiff or full soft...
Old Mar 1, 2011, 05:29 AM
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How does one do that?
Old Mar 1, 2011, 08:16 AM
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My car also started doing this. When under full throttle acceleration it stutters until it's in the higher rpm. I have a crushed stock bov.
Old Mar 1, 2011, 08:24 AM
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Originally Posted by nohlan_4
My car also started doing this. When under full throttle acceleration it stutters until it's in the higher rpm. I have a crushed stock bov.
It shouldn't do it when you're WOT. It's typically an issue at part throttle where the pressure in the intake manifold is near 0psi boost.

In your case, I'd be more inclined to think it's a boost leak, or maybe worn out spark plugs.
Old Mar 1, 2011, 08:33 AM
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Hmm...never thought of that before. I originally thought it was clutch slippage but they way it's surging it doesn't feel like it. It also doesn't do it if I ease into the throttle.
Old Mar 1, 2011, 03:34 PM
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i deffinately think mine is cause of a leaking intercooler, wrecked the car and bent up the intercooler, im running a tial q, car ran perfect before the accident.
Old Mar 3, 2011, 06:18 PM
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I have a turbosmart dual port BOV. It's not the stock so that's how I was able to set it to hard


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