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Bov Making Car Hunt?

sleptema

By sleptema,
in Engines & Forced Induction

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sleptema Proficient

sleptema

Posted
Posted

Hi all.

Tried to search for the issue, but I didn't have much luck finding anything relating directly to my issue.

Car has a stock blow off valve, plumbed back. Decided to make a plate to block it off, you know for flutter/dose/compressor surge whatever you want to call it.

Car runs great, starts fine, idles fine, holds boost, flutters...

But if I am idling and rev it slightly, then take my foot off the throttle, it hunts for a while then goes back to idling fine. Sometimes it drops to 100-200 rpm, sometimes just to 600, stalled a couple times. It doesn't ALWAYS do it. It is mainly a concern when I am in traffic and need to move forward slightly. Black smoke also comes out the exhaust when hunting. Rich?

Is it because it was tuned with the plumb back blow off and it is expecting that air for idle and isn't receiving it? I have blocked the vacuum line going to the bov and the plumb back pipe. I haven't tried plumbing the bov back in and taking out the blanking plate. Will do that soon and report back.

R34 gt-t rb25det neo
Garret low mount on 18psi
avc-r boost controller
power fc

supporting mods

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https://www.sau.com.au/forums/topic/438450-bov-making-car-hunt/
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Ben C34 Grand Master

Ben C34

Posted
Posted (edited)

It's because of the reverberation caused affecting the afm.

The ecu sees it as more airflow and adds fuel.

Flutters are not cool enough to put up with your car running shit.

Edited by superben
ARTZ Grand Master

ARTZ

Posted
Posted

Or plumb it back and live a happy life. :)

this...seems pretty simple to me mate...you changed something and it made it worse...

Now 'Im not the sharpest tool in the shed but i'd thunk the smart thing to do would be change it back ;)

89CAL Grand Master

89CAL

Posted
Posted

Mine fluttered with an AFM, had the bov plumbed straight into the intake pipe at 90 degrees, not facing the turbo as recommended. Never had any issues

Mine didnt flutter like crazy because I softened the bov but when it did it was fine

sleptema Proficient

sleptema

Posted
  • Author
Posted

Mine fluttered with an AFM, had the bov plumbed straight into the intake pipe at 90 degrees, not facing the turbo as recommended. Never had any issues

Mine didnt flutter like crazy because I softened the bov but when it did it was fine

If it flutters, the BOV is supposed to be blocked, doesn't matter if it is plumbed or not..

sleptema Proficient

sleptema

Posted
  • Author
Posted

Yeahhhhh.... It will flutter blocked or with the BOV spring tightish. It isnt 'supposed' to be bocked

How do you tighten the BOV spring?

I didn't think the flutter would have have as much as effect as it did on my car, it is a low mount garret with a LARGE FMIC, and no forward facing plenum. So much frikken pipe work, wouldn't have thought it would have made it that far back..

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