I know I may sound like a newbie or something but my blow off valve (blitz) is making a fluttering sound during shifts instead of a smooth "whoosh". I though is was due to a vacuum signal but I check that out and it was fine. What else can be making it do this?

Also, I tried turning the valve at the top both out and in and it seems to help nothing. Do I need to just get a different bov.

www.xlr8shen.com

I believe your blow off valve is working perfectly fine. I have a Greddy Type S BOV and it all depends on how much boost you are building when you shift (certain BOVs are made strickly for higher pressures). If I am just doing normal driving, not pushing the car, and shift around 3,000 rpm (0-1 psi) the valve will release and sound like a turkey (flutter). It is only when I push the car and build more boost (6 psi - Stage II), that I get the smooth release sound. Also the adjustment on top of the blow off valve (not sure what the Blitz valve looks like) is to adjust the pressure at which the BOV releases. If it is too soft, you will hear it release too early and not build the full pressure your kit is capable of (depending on the wastegate setup).

Hope this helps,
Kurt

depends on how much boost your running. If you not boosting a lot then it won't open as much. Trying hitting full boost and letting off on the pedal you should get a loud sound haha then you car will buck back and forth hehe.

Is the vaccum line for the BOV tee'ed off of something or ran to its own vaccum source? if its tee'ed off something, it could cause it to flutter when releasing.




www.TeamKLR.com
1997 Silver RS
12.3@118mph,20psi, race gas(drag radials)
Wiseco 10.5 Pistons
Eagle Rods
Started as a manufactured turbo kit, now its a custom one!
Vortech FMU
Greddy Exhaust
440cc Injectors

Waiting on the EVOlution!

Yeah, I think that may be it. I had the vaccuum line teed so I will try running it straight and see how it does.

Hey guys don't you have to tee the line from the bov to the intake manifold because of the boost controller? That is how mine is setup, and I do have compressor surge. How can you just run the vac line from the bov straight to the intake mani if you have a boost controller? Thanks for any insight.

On my old turbo car the BOV line was run directly from the intake manifold to the BOV. The MBC was directly from the compressor housing to the boost controller to the wastegate actuator. Thats the best way I see to run them.

Originally posted by 740 turbo brick
On my old turbo car the BOV line was run directly from the intake manifold to the BOV. The MBC was directly from the compressor housing to the boost controller to the wastegate actuator. Thats the best way I see to run them.

same here

I dont have a compressor housing fitting on my t3/t4 turbo so what to do???

Originally posted by FreikDog
I dont have a compressor housing fitting on my t3/t4 turbo so what to do???

post a pic

I will post pics of the way it is set up now, and describe for now. Basically if I was to run the bov line straight to the intake mani, would I just run the mbc off the intake mani, and then to the wastegate. I do have an extra nipple on my intercooler piping by the throttle body I could use I suppose. Any thoughts????

Originally posted by FreikDog
I will post pics of the way it is set up now, and describe for now. Basically if I was to run the bov line straight to the intake mani, would I just run the mbc off the intake mani, and then to the wastegate. I do have an extra nipple on my intercooler piping by the throttle body I could use I suppose. Any thoughts????

yes, post a pic of your turbo of all angles.

For what its worth, My HKS SSQV (and my TIAL 50MM) had the flutter sound at low boost (under 10PSI). The flutter was very dependant on the intake of the turbo. If I put the filter directly on the turbo, the flutter went away. If i moved the filter even 3" off the turbo the flutter came back. Not sure why.

Right now my filter is in the bumper and I get no flutter from the Tial 50MM.

Terry

Hey guys. I just finished installing Portfueler on my car and with the addition of a MBC I am now making around 20psi of boost whereas before I was hitting around 10psi. Everything seems fine, except for some reason now when I let off the gas under boost my Greddy Type S BOV flutters instead of having a nice smooth release like it used to. I have the same vaccum line running to it, and I even took it apart to check everything internally and it looks fine. Weird thing is, at low boost levels, like 4-8psi, it still sounds normal. Its only when I really get on it that it sounds weird and flutters. Sounds counter intuitive if you ask me

Anyone know why this would happen?

*Update* I did what the dudes on the Evo forums who run the Type-S do. I removed the small inner spring from the BOV and tightened the set scew about 3 full turns from when it first contacts the spring plate. This totally got rid of the flutter sound I was seeing. If any of you guys out there are running the Greddy Type-S and can not get it to sound right or are seeing compressor surge, I would def try this before you go out and spend money on a new one.