to BOV or not...
Jul 28, 2008, 08:57 PM
#1
to BOV or not...
ok before everyone starts chewing my head off about getting a BOV, let me explain. awhile back i was complaining about fluttering sound after my works re-flash. ive been doing a lot of research and found that its my stock bov, believe or not, its not holding boost. might just be my unit. its not compression surge because it doesnt sound like this...
http://www.youtube.com/watch?v=MkkA-...eature=related
the flutter comes in before i shift, at high rpms, and before the swooosh sound. other mods i have is cai+works re-flash. now my 1st question is should i just get another stock unit, doubt im still under warranty, or am i better off going aftermarket? 2nd is it normal when im reaching boost limit of 21psi is the needle on my boost gauge suppose to bounce like crazy.
http://www.youtube.com/watch?v=MkkA-...eature=related
the flutter comes in before i shift, at high rpms, and before the swooosh sound. other mods i have is cai+works re-flash. now my 1st question is should i just get another stock unit, doubt im still under warranty, or am i better off going aftermarket? 2nd is it normal when im reaching boost limit of 21psi is the needle on my boost gauge suppose to bounce like crazy.
Jul 28, 2008, 09:27 PM
#2
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your bov flutters at 21psi? that is not normal, find someone with a stock unit and try that. make sure all your pipes are tight and what not.
boost should be pretty stable, it should hit max boost and taper, shouldn't bounce around
boost should be pretty stable, it should hit max boost and taper, shouldn't bounce around
Last edited by JoeyM3; Jul 29, 2008 at 08:32 AM.
Jul 29, 2008, 07:53 PM
#4
dont know anyone with another X. pipes are tight. no leaks, none that i know off. boost does raise normally but when it reach say 21psi-23, the needles bounce, kinda like your RPM before redline. also i notice that its worst when its warm out side, no so much in the morning.
Jul 30, 2008, 01:16 AM
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I have the works flash and my BOV does not flutter as you described in your situation. They data logged my car and my boost peaked at 24.5-25 at certain spots. And tapered down to 18-19. If this helps I have a GReddy DP, drop in filter and Greddy TIC catback. But I never heard my BOV flutter, and I have had my tune almost a month. Try to get the works diverter valve, looks stock but has a stiffer spring.
Jul 30, 2008, 09:46 AM
#7
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been running the GFB Stealth FX and havent had a prob since. I'd make sure the rtn vacuum line is all the way on the small nipple (I said nipple 
)
and make sure its not cracked/torn anywhere. There could be a boost leak somewhere...but if your sure its the BOV fluttering (try to boost, then let off a little and see if it flutters the vent), it could be that the BOV has issues...but those are rare instances.
)and make sure its not cracked/torn anywhere. There could be a boost leak somewhere...but if your sure its the BOV fluttering (try to boost, then let off a little and see if it flutters the vent), it could be that the BOV has issues...but those are rare instances.
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Jul 30, 2008, 08:34 PM
#9
been running the GFB Stealth FX and havent had a prob since. I'd make sure the rtn vacuum line is all the way on the small nipple (I said nipple )
and make sure its not cracked/torn anywhere. There could be a boost leak somewhere...but if your sure its the BOV fluttering (try to boost, then let off a little and see if it flutters the vent), it could be that the BOV has issues...but those are rare instances.
)and make sure its not cracked/torn anywhere. There could be a boost leak somewhere...but if your sure its the BOV fluttering (try to boost, then let off a little and see if it flutters the vent), it could be that the BOV has issues...but those are rare instances.
1st gear is fine to 2nd then 3-4, it flutters before it psssshhhhh.a lot of people are saying its normal. as long as it doesnt sound like the above video. not going to SCM unless my wheels are falling off, quite a drive.
Aug 2, 2008, 07:40 PM
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That happened to me once after I had my clutch installed. One of the vacuum lines had a small tear in it, causing the car to overboost and make that "sound". Changed out the hoses and double checked everything was hooked up properly from the boost solenoid and it was good to go.
Aug 2, 2008, 09:06 PM
#11
That happened to me once after I had my clutch installed. One of the vacuum lines had a small tear in it, causing the car to overboost and make that "sound". Changed out the hoses and double checked everything was hooked up properly from the boost solenoid and it was good to go.
Aug 16, 2008, 08:33 AM
#12
Just wanted to chime in here and mention I'm also seeing the following flutter:
Boost to 24 PSI in 5th and the needle is rock steady and holds from 3000-5000 without any extra movement.
When I am boosting in 2nd, 3rd, or 4th gear my boost gauge needle is fluttering 2-3 PSI very rapidly making it hard to tell what boost I'm running. I don't hear any bad sounds from the BOV with the windows down and it sounds fine when venting back to the intake pipes.
What boggles me is why 5th gear seems fine yet the other gears it does this screwy behaviour. I'm going to troubleshoot this more today and verify that it does it in the lower gears at 3000-4000 RPM as well, could just be a high RPM thing and topping out 5th isn't wise if I want to keep my license just to "test" it.
The Boost gauge is tapped into a T about 3 inches from the intake manifold that also supplies boost to the stock Evo X metal BOV. Also what Boost pressure have these been known to hold before leaking? If this is part of the issue I may crush it to hold a couple more PSI.
Boost to 24 PSI in 5th and the needle is rock steady and holds from 3000-5000 without any extra movement.
When I am boosting in 2nd, 3rd, or 4th gear my boost gauge needle is fluttering 2-3 PSI very rapidly making it hard to tell what boost I'm running. I don't hear any bad sounds from the BOV with the windows down and it sounds fine when venting back to the intake pipes.
What boggles me is why 5th gear seems fine yet the other gears it does this screwy behaviour. I'm going to troubleshoot this more today and verify that it does it in the lower gears at 3000-4000 RPM as well, could just be a high RPM thing and topping out 5th isn't wise if I want to keep my license just to "test" it.
The Boost gauge is tapped into a T about 3 inches from the intake manifold that also supplies boost to the stock Evo X metal BOV. Also what Boost pressure have these been known to hold before leaking? If this is part of the issue I may crush it to hold a couple more PSI.
Aug 16, 2008, 09:01 AM
#13
Just wanted to chime in here and mention I'm also seeing the following flutter:
Boost to 24 PSI in 5th and the needle is rock steady and holds from 3000-5000 without any extra movement.
When I am boosting in 2nd, 3rd, or 4th gear my boost gauge needle is fluttering 2-3 PSI very rapidly making it hard to tell what boost I'm running. I don't hear any bad sounds from the BOV with the windows down and it sounds fine when venting back to the intake pipes.
What boggles me is why 5th gear seems fine yet the other gears it does this screwy behaviour. I'm going to troubleshoot this more today and verify that it does it in the lower gears at 3000-4000 RPM as well, could just be a high RPM thing and topping out 5th isn't wise if I want to keep my license just to "test" it.
The Boost gauge is tapped into a T about 3 inches from the intake manifold that also supplies boost to the stock Evo X metal BOV. Also what Boost pressure have these been known to hold before leaking? If this is part of the issue I may crush it to hold a couple more PSI.
Boost to 24 PSI in 5th and the needle is rock steady and holds from 3000-5000 without any extra movement.
When I am boosting in 2nd, 3rd, or 4th gear my boost gauge needle is fluttering 2-3 PSI very rapidly making it hard to tell what boost I'm running. I don't hear any bad sounds from the BOV with the windows down and it sounds fine when venting back to the intake pipes.
What boggles me is why 5th gear seems fine yet the other gears it does this screwy behaviour. I'm going to troubleshoot this more today and verify that it does it in the lower gears at 3000-4000 RPM as well, could just be a high RPM thing and topping out 5th isn't wise if I want to keep my license just to "test" it.
The Boost gauge is tapped into a T about 3 inches from the intake manifold that also supplies boost to the stock Evo X metal BOV. Also what Boost pressure have these been known to hold before leaking? If this is part of the issue I may crush it to hold a couple more PSI.
man that'll be soo great! thanks. im still having the problem. ive tried everything but adjust the actuator rod and changing out the bov.
Aug 18, 2008, 06:52 PM
#14
Ok after this weekend I've found that the boost flutter only happens in the upper RPM's which seems odd to me. What could possibly be causing this based on higher engine RPM's? In 3-5 gear it is rock steady at 2500-4500 RPM before it goes nuts.
I also decided to throw caution to the wind and slightly crush the Stock BOV to hold higher boost and see if that reduced the flutter. Sadly I didn't have time to test opening pressure before and after so I'll have to check someone's stock BOV sometime in the future and compare when I have a pressure rig ready to go.
If you open throttle at under 3000 RPM and build 10 PSI, then let off partially but not all the way, you get that annoying "chooo choo choo choo" sound of the BoV fluttering. It doesn't do it at 3k+ RPM's but for the life of me I can't remember if it did this at all stock before I crushed it. So if stock it doesn't do that I may have crushed it too far, but at least it will be holding more boost.
I'm pretty sure that the flutter at low boost and RPM is not turbo damaging from what I read but if it occurred at higher RPM's and boost I can see why some overly stiff aftermarket BOV's would make daily driving a headache. Full throttle and then fully off throttle and it never does that flutter even at the lower RPM.
http://www.youtube.com/watch?v=jEUWE...eature=related
After watching that video I guess the side effect of making the BOV stiffer by crushing it may have made it too stiff to dump pressure at low RPM's where you let off the gas but stay in part throttle. I may try shortening the boost signal to the BOV since it's now only 2 feet from the Intake manifold which may help it a bit. I'll report back to see how it impacts the boost needle at higher RPM's.
I also decided to throw caution to the wind and slightly crush the Stock BOV to hold higher boost and see if that reduced the flutter. Sadly I didn't have time to test opening pressure before and after so I'll have to check someone's stock BOV sometime in the future and compare when I have a pressure rig ready to go.
If you open throttle at under 3000 RPM and build 10 PSI, then let off partially but not all the way, you get that annoying "chooo choo choo choo" sound of the BoV fluttering. It doesn't do it at 3k+ RPM's but for the life of me I can't remember if it did this at all stock before I crushed it. So if stock it doesn't do that I may have crushed it too far, but at least it will be holding more boost.
I'm pretty sure that the flutter at low boost and RPM is not turbo damaging from what I read but if it occurred at higher RPM's and boost I can see why some overly stiff aftermarket BOV's would make daily driving a headache. Full throttle and then fully off throttle and it never does that flutter even at the lower RPM.
http://www.youtube.com/watch?v=jEUWE...eature=related
After watching that video I guess the side effect of making the BOV stiffer by crushing it may have made it too stiff to dump pressure at low RPM's where you let off the gas but stay in part throttle. I may try shortening the boost signal to the BOV since it's now only 2 feet from the Intake manifold which may help it a bit. I'll report back to see how it impacts the boost needle at higher RPM's.
Last edited by Hiboost; Aug 18, 2008 at 11:28 PM.
Aug 19, 2008, 10:57 AM
#15
Small update: Tried a shorter signal line to the BOV and it is more pronounced than ever in the mid RPM's but oddly is steady at low RPM's and high RPM's. I may try removing boost line to the BOV as a test but it may be leaking from the IC pipe to BOV side.
Are there really no other people seeing this behaviour on their boost gauge?
Are there really no other people seeing this behaviour on their boost gauge?