Weird BOV sound (pics+vid pls help)

[necrotopsy]

this is 14 psi. it's a greddy type RS. as you can hear when you watch it it goes tu-tu-tu-tu and not whoosh. any sugestions?

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[GsXdSmKingGsX]

Its compressor surge or flutter my friend even though you insist it isnt.

 

[hurricanecris24]

i believe thats how the rs is supposed to sound

 

[GsXdSmKingGsX]

i believe thats how the rs is supposed to sound

Oh god no man. not even close

 

[hurricanecris24]

im wrong

 

[necrotopsy]

okay well if you think it's comp surge what would your suggestion be?

though i've had several people i trust tell me that it's not comp surge

 

[GsXdSmKingGsX]

just not as drastic as his is. Its kinda like it but not as healthy sounding

It depends. You have no mod list .

 

[necrotopsy]

oh right.. hahah sorry. here is the engine specs:

Star turbo manifold w/ external wastegate
Garrett T3/T04E hybrid
Hahn big front mount intercooler
Greddy Type-RS BOV
JE Pistons 8.8:1 CR
Eagle rods
Ported and polished head with pt lifters and rockers
60mm throttle body
walbroh 255HP fuel pump
stillen 1:1 fuel pressure riser
8 injector set up with 034eic - stock (210cc) primaries and 60#(610cc) secondaries
Coolingmist water injection
3" turbo back mandrel bent exhaust
Spec Stage 4 clutch
5 speed swap w/ short shifter
symborski shift kit
solid front and rear motor mounts

oh, it's tuned for and handles 25 psi. 15 psi for street and it does this. seems like 20 psi it doesn't do it--- i lied it did it even at max boost, but only twice vs. 4 times in lower boost)

 

[GsXdSmKingGsX]

What kind of boost are you running? compressor surge can happen when you BOV doesnt open of the diaphragm or seal is broken

 

[necrotopsy]

boost was added at end of one post. that video is 14 psi. and i run 15 for street. but it sounds like this from 1 psi to 15 psi. maybe not for 20+... by that time engine/exhaust/wastegate is so loud it's hard to hear the BOV--- it does do it even at 26 psi. TU-TU vs TU-TU-Tu-tu at lower boost

 

[GsXdSmKingGsX]

just check the seals and diaphragm on your BOV and then get back to me

 

[necrotopsy]

have to wait untill the morning.

 

[GsXdSmKingGsX]

sounds good buddy. Ill be looking for this thread

 

[necrotopsy]

the diaphgram had a wrinkle in it. and now it's wore more in the area than anywhere else. i straightened it out, but idk...

i should probably replace it?

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[tec_41]

I had a similar sound once...fixed it by tapping a better vac source with bigger hose.

 

[necrotopsy]

dunno if i can do that, i'm already using the biggest hoses that fit. besides if you look at the pictures i think it's the bov that's the problem. but i've never seen a bad bov so idk.

 

[TSimage]

Its a toss up.. May be time to upgrade to a better BOV anyways. Those Greddy BOVs are junk, even the knock off NGR versions of them are better (improved diaphragm) Your video is definitely surge and your only other way to fix it is to loosen up your bov adjustment screw. What happens is on cars that run more boost they have to tighten it down so that it isn't blown open during boost. If you run lower boost however, like you do, you have to loosen it or else it wont open fast enough/wide enough to let all the air escape, thus the fluttering sound. What this means is that that back pressure is reaching your turbo which is no bueno..

 

[necrotopsy]

i was thinking about doing the spring mod. take out one of the 2 springs.
'
but i was hoping for a BOV i could run at both 15 PSI and 25 PSI...

 

[JusMX141]

i was thinking about doing the spring mod. take out one of the 2 springs.

This isn't a "mod", this is what is required on certain applications in order to prevent the BOV from killing the turbo.

Lose the little spring- use the big one ONLY. Tune the valve with the adjusting screw so it's either slightly open (1/8" or less) or just barely closed at idle.

Had you kept the valve as stiff as it was it would have eventually caused your turbo to fail.

but i was hoping for a BOV i could run at both 15 PSI and 25 PSI...

When on boost, the amount of pressure the valve should hold with the quick-release feature disabled is indefinite....there is as much boost pressure filling the upper chamber and holding the valve shut as there is in the piping trying to push the valve open.

 

[necrotopsy]

oic. thanks jusmx.

 

[Bluefire16]

This isnt compressor surge. Justin and Tsimage have it correct however. You need to loosen your BOV, it is set to hard, and not able to release enough air.

The whole compression surge thing has been debated and debated and often is confused.

Here is a video of true compression surge. True surge happens under load, not when letting off and shifting.

YouTube - True Compressor Surge

Do some searching this has been beat'n a million times.

 

[JusMX141]

There are actually two types of surge...one which happens under load, and one which happens when the throttle plate is closed and air cannot escape. A compressor bypass valve is in place to protect the latter form of surge. If your compressor bypass valve is too stiff, you may as well not have one at all.

 

[necrotopsy]

so would you recommend i just tak the smaller spring out, take the spring out and loosen it, or just loosen it? trying to not have to take it apart 100 times if i don't have to.

 

[Bluefire16]

No, just loosen the bov itself. Normally there should be a screw on top. Right to tighten it, which would require more air and pressure to open it. And to the left, to loosen it.

So just turn the screw to the left a tad and loosin it. On most there is a stem piece and a nut. Normally you loosen the nut and then adjust left or right to tighter or loosen using a allen wrench. Then retighten the nut to hold it in place.

 

[necrotopsy]

yeah the nut on top of the BOV is already as loose as it goes while still being tight enough to stay on.

i guess i'll try the single spring and see if that works.