Search temporarily disabled as everyone knows, so I don't know if this has been asked before. I looked at the FAQ thread and found nothing.

89 civic Si hatch OBD 1 conv. P28 Neptuned and tuned. 240 WHP Drag kit with blitz BOV and Tial 38mm

BOV teed into intake manifold

It always makes that fluttering sound when it blows off. If it makes a difference, I have the filtered tip on it right now. I have tried all the way tight, all the way loose, and just about everywhere in between.

Any suggestions?

In layman's terms, my car doesn't go "whoooooosh" like everyone else with a turbo. My BOV sounds like it is on crack or something...

It sort of sounds like chipachipachipachipachipachipa

 

Compressor surge.

Where on the intake manifold is the vacuum source coming from before the tee? FPR? Single dedicated source?

 

yeah agreed. i have found that the PCV is a great place to tee unless you have provisions for a dedicated source.

 

Of all things related to motors, vacuum is one of the things I am least familiar with. It is a complete mystery to me. I understand how it works by the pistons sucking in air and fuel, and that certain systems are powered by vacuum, but aside from that, I am clueless, especially when it comes to runnin vacuum lines...

The only one I could find with the same diameter vacuum hose was the one that goes from the top of the intake manifold to that round thingy on the front.

I have tried teeing it off the brake booster, and off the FPR, but that did not help the issue...

Here are some pics...

 

But my PCV seems to have a light coat of oil inside it... wouldn't that be bad for the BOV seal?

 

as long as the hose you have pictured has manifold vacuum, it will work.

 

It does have vacuum, and so did all the other sources I had it teed into, so why is the BOV not functioning correctly?

 

Maybe the valve is defective... can you open the valve manually?

 

Yes. It has been doing this since the first time I installed it about 3 years ago. I'm sick of the crappy sound, which is why I started this thread. After it made the sound the first time I drove my car with the BOV installed, I did some research, and found out that it might be dust or debris built up around the piston seal inside the BOV, so I popped off the top, wiped out the inside with a damp rag and dried it off with compressed air. I put it all back together, and that did not help the problem at all. I was hoping that it was just an issue with tuning, but I got my car tuned last month for the first time, and it is still doing the same thing.

 

Also, I noticed that my car doesn't blow off unless it is under a load. I don't know if that is normal for hondas, but I don't see why it should be different from other types of vehicles which can blow off under zero load...

 

you were driving around for almost 3 years untuned!?

is it a real blitz bov, or a knockoff one? i know the knockoffs can be more prone to failing, or being defective from day one. i suppose even if you do have a real one maybe you just were unlucky for whatever reason and it was DOA. don't some of these bov's have double internal springs. i think i recall reading something that someone mentioned in another thread about taking one of the springs out, and it made it finally work the way it was supposed to. i forget who made the original post but it was only like a week or 2 ago

 

Well, I ran it untuned because the DRAG kit came with an FMU and a MAP bypass valve. It worked ok, but I wasn't out redlining it for obvious reasons. I don't want to get into my mentality at that time, but a lot of it had to do with a severe lack in understanding how turbocharging and fuel management work. Trust me, I have come a LONG way since then...

Anyway, I hope it is a real one considering it was the one included with my turbo kit from DRAG, and the fact that it came in a blitz box with all sorts of asian writing all over it. It has been so long since I popped off the top that I can't remember if there were 2 springs in there. I read somewhere that the type I have is called a DD (dual drive). I don't know how to set it to the lower setting since I have long since thrown the box and instructions away. In fact, I don't even know how to tell what setting it is on exept for the little adjuster thingy on top of it which hasn't helped at all. I will have to pop the top off again and take a look in there and see if I can find 2 springs...

 

Crap, it's raining outside. Maybe I'll do it tomorrow

 

If it is a small amount of flutter at a low psi level, say only 2-6psi regardless of turbo, it is rather normal, since you are simply taking the car out of vaccum briefly, and the BOV wants to vent ANY excess pressure. Almost all BOVs do that, and generally is not a problem unless you're going into higher boost pressures and releasing causing reversion. If you're getting picky about that flutter a 2-5 psi, better get used to it. Based upon your pressure source, you don't seem to be in a bad spot, so this should be ok.

Hondas normally don't blow off unless underload due to the lack of pressure that they can make at vaccum compared to most other turbo-factory cars that use a MAF. The tighter you make the spring, the better it will hold off on higher pressures, but also, the more reversion you may create at the lower pressures, because the spring can't vent the excess pressure, so just be careful.

 

Shodan beat me to it, i was going to say something similar. My car does the chachacha when im like on boost half throttle a few psi, but when i floor it and shift at high rpm with 10-15psi it does NOT do the chachacha.

 

I don't know if you consider 9 lbs of boost low, but mine does the chachacha even when it is a full boost, which is 9lbs for me. I'm going to take it apart today. I'll try and post some pics

 

OK, so here is what I found inside. Only 1 spring. If felt like it was a little too stiff. I think that it is too stiff to open when there is little pressure. I tried pushing on the piston with the spring still in it, and it was pertty hard (even with the adjuster completely out).

I went ahead a put a light coat of gun oil in there anyway to see if it would help.

I put everything back together, and that didn't help at all. Still same thing. Even at 9 PSI. Is it possible that I got the wrong spring. Blitz has 2 different springs on their website, but they also say that the BOV should come with the standard spring...

I don't know what else to do.

 

Thats a rather tall and stiff "looking" spring, people with greddy bov have cut coils off there spring before to fix the minor flutter, 9psi it should open clean and not chachacha, some bovs do chachacha though, if you have a 2step i would hit that with the hood open, have someone stand out side near the engine bay and see if the noise is comming from the bov or from the turbo, if the noise is comming from the bov its fine, if its comming from the turbo then you could have a minor problem...

 

Here is a shot of the Dual Drive. I guess the smaller opening at the bottom is for "low boost" and the bigger one is for higher boost. I don't see how this design would make it any more efficient or responsive. Seems like it would just be more restrictive than anything. In fact, now that I think about it, what if the fluttering sound is the piston opening up past the smaller opening and into the larger opening for fractions of a second? Perhaps it is actually releiving pressure well enough, but it sounds wierd because there isn't enough pressure to keep it open past the larger opening.

Ugh! This is rediculous! Now I don't know if it is just a wierd design or if it is because the spring is too stiff.

I don't know about cutting the spring. I think I might try to call a place that sells the replacement springs to find out how stiff it is supposed to be. Maybe I got the "hard" spring...

 

another shot of the dual drive

 

Then why not do as i suggested?

 

That's just Blitz. They sound like that very easily at 9psi for their dual drive. Get over 14psi with it, and it will not happen.

I'd be against cutting the coil. That is outside their scope of design.

 

Not what I wanted to hear. Why would they design it that way? isn't that bad for the turbo?

Anyone know of any BOV that work/sound well with low boost applications?

 

What do you mean? Cut the spring? It looks like the spring is designed to be perfectly flat on top and bottom, so won't that change the angle at which the spring sits and ultimately cause the piston to move at awkward angles?

 

All will flutter on average at 9psi or under except for the HKS and Greddy Type RS BOVs. The Turbo XS Type H line doesn't flutter either, but I don't like their design. If you think you're picky now, the Type H will really **** you off with the "washer" system that they use to change the spring rate, as well as the piston in the valve having a tendency to freeze up over time.