Is the check valve in the vacuum line turned the right direction? That's my only guess.

 

Check valve?

Patrick

 

I have a HKS SSQ on my turbo Honda and it has an in line check valve in the vacuum line. Can't remember which way the flow is supposed to go though. It comes with the BOV. My friend has one on his WRX and it has the check valve also. The check valve will only allow air to flow in one direction in the line. I'm thinking air should flow towards the BOV.

 

Hmmm I remember what you are talking about, it's like a little black disk? I used to have that on when it was on my WRX but some of the Subaru guys around here said I didn't need it and made me throw it away lol. They said it was just a filter and was totally unnecessary.

Interesting.

Patrick

 

Nope! Definitely a CV. I could blow thru it on direction and not the other. You can get them at any place that sells aqaurium supplies. Hope this helps.

 

what's a compression surge?

 

what's a compression surge?

Compressor surge is when the throttle plate closes and the built up boost from the turbo has nowhere to go, and it backs up into the turbo and stalls the compressor. It's VERY bad as it puts a ton of uncessesary stress on the turbine and can cause alot of problems.

In my case it's a heavy fluttering sound when you let off the throttle. Instead of the BOV sounding I get a heavy fluttering from the turbo.

Well for now I decided to put the BPV back on and everything works fine until I can figure out what's causing all this.

Patrick

 

my friends evo is like that. he has the GReddy type S bov, and if he lets off slowly he gets the flutter. he has to let off his foot quick in order for it to not do that. so maybe its just the bov and you have to release your foot quickly? i have a SSQV on my del sol ( older style one though) and i never get that.

 

Well if I let off quickly I don't get it, but it just happens too much for my comfort when I think about what it's doing to my turbine

Oddly enough, if I engauge the clutch fully and then let off the gas, it works fine, but if I let off the gas and then push in the clutch I get flutter. It seems to only happen when I have friction on the drivetrain like that. Strange.

Patrick

 

hm, strange.

i hear you though, i wouldnt want to screw up anything either.

did you try looking up the hks ssqv online and seeing if your missing anything?

 

The flutter is most likely the Sequential part of the SSV. It does the ricey flutter at low boost, then full BO at higher boost. That's not likely compressor stall, that's just what they sound like. Of course I don't like BOV's at all:

http://www.siegelracing.com/bov.htm

SS

 

I'm running the hks also with the Turboxs fmic and recirculation fitting back to the intake. The flutter at low boost is just how this bov sounds and at higher boost it just releases pressure at once. It's not compressor surge.

 

The aperture on the HKS SSQV is something like 33-38mm. I highly doubt you're getting compressor surge, and if you are it's from an improper functioning BOV.

 

vostok, do u have an aftermarket intake?? sounds like wastegate flutter to me...mine does it all the time, right before u hit boost and let off the gas, the sound is very apparent...

 

Compressor surge is when the throttle plate closes and the built up boost from the turbo has nowhere to go, and it backs up into the turbo and stalls the compressor. It's VERY bad as it puts a ton of uncessesary stress on the turbine and can cause alot of problems.

In my case it's a heavy fluttering sound when you let off the throttle. Instead of the BOV sounding I get a heavy fluttering from the turbo.

Well for now I decided to put the BPV back on and everything works fine until I can figure out what's causing all this.

Patrick

Sounds like wastegate flutter to me. Sounds like the BOV isn't blowing off at all. On my Honda, before I installed a BOV, Excess air fluttered through the wastegate when I let off the gas or pressed the clutch. Sounded like a rattle snake under the hood sort-of.

 

Compressor surge is when the throttle plate closes and the built up boost from the turbo has nowhere to go, and it backs up into the turbo and stalls the compressor. It's VERY bad as it puts a ton of uncessesary stress on the turbine and can cause alot of problems.

In my case it's a heavy fluttering sound when you let off the throttle. Instead of the BOV sounding I get a heavy fluttering from the turbo.

Well for now I decided to put the BPV back on and everything works fine until I can figure out what's causing all this.

Patrick

wait, so im cunfised, what is the difference in soudnd between waste gate flutter and fluttler fromt eh stall of the turbo



0-spyder

 

like i said on NASIOC...its the design of the SSQV that makes it sound like comp. surge at low boost. I know because I'm hearing the same thing with my 20G, SSQV and FMIC setup. As long as you're not getting the comp. surge sound at high boost you're fine and you're BOV is fine too.

 

dude sounds like your SSQV is jacked...I have gotten the flutter if I slowly let off the gas intentionally, but that puppy whistles while the car works.

 

Lots of misnomers floating around this thread...

Compressor surge is from an improperly sized turbo and it's basically where the compressor side is too big for the exhaust side. On a compressor map, it's when you go past the surge line. It's trying to push too much air for the speed it's spinning and the air backs up and pulses back and forth into the compressor making a similar noise but only under full boost at certain RPMs.

Compressor stall is the momentary pulsing of air back into the compressor due to a blockage in the intake tract- like the throttle plate closing. This is what happens with a messed up or no BOV. It's not as doom and gloom as people make it out.

Wastegate flutter is not a common term but but in my experience, it would be the inability for the boost solenoid to regulate boost properly and it 'hunts' to find the right level- opening and closing the wastegate. Much like hitting warning boost on an aftermarket boost controller. But I could be wrong on this one. It could be a term that was made up by someone to describe compressor stall and now it's a common misnomer.

I've experienced all of these at some point in my car life.