I just got a used hks bov, and it works ok, but only after I shift after full boost and shift fast. Its a used bov, and the adjustment screw is broken, what I want to know is how the screw adjusts when the bov will blow off. I want it to sound when i just rev it hard. So i can be a ricer of course. does the screw just adjust how much of the vac/boost signal the bov sees, so could i just rig up a regulator valve myself to adjust it? Thanks,
Chris

 

It's not going to work when you "just rev it hard" because it works on a vacuum. The engine won't create a vacuum when it's not under load. Your blow off valve is releasing pressure built up by your turbo, so if you don't see the boost gauge moving, guess what? No pressure to release, hence, no "blow-off".

 

Blow off valve, simple, it releases compressed air from the Upper IC pipe so it doesn't slam back into the compressor wheel possibly damaging the fins. There is no adjustment to when the valve "blows off". Like $100T2 said, if the engine's not under load then boost isn't being made because the wastegate is open, no boost means no compressed air in the IC pipes, which means nothing to blow off.

 

yeah...I wonder how i see movie clips of cars reving and having blow off valves going . also i want to adjust it so it will blow off between shifts easier, b/c now it will bearly go and sometimes not at all.

 

Just the opposite. Engines create more vacuum when under less load. Slam the throttle shut and vacuum goes to max.

 

Because movies are not real life. Welcome to reality, jump on in, the water is fine.

 

Please dont tell me you cant adjust them man...that I know you can do. can anyone else with one back me up here. You simply adjust the point where it relieves pressure if im not mistaken. the movie clips are of real cars not tfatf. Im talkin vid clips somone took of their car. If you really cant and im just absolutly retarded Im sure someone will be so kind as to let me know.

 

Haven't you guys ever heard any decent turbo car rev? I hear THEIR BOVs.... you can get a little boost by reving on some cars, but not much. Unless whomevers 3rd gen I was standing to has that fake BOV

 

Well if you open up the intake an exhaust you can get some boost with it in neutral. Its not going to be too loud without enough boost either.

 

I have a Turbo XS-H and its adjustable with the tension of the springs .. you add & remove washers to make the spring tighter & looser.

 

I can make boost in neautral with my mods, but it builds slowly

 

the way the BOV adjusts it is by the spring forces. If you compress the spring more, it applies more force, hence it takes more pressure to open the valve. Since the vac line at the top of the Valve is bringing in air at the same pressure when on the gas, but different when you shift, the valve will open. It will do it in neutral. Try revving it, backing off, and revving again while high in the RPMs (maybe even around 3k-4k) and it should be enough of a pressure DIFFERENCE (not exactly boost) to make the valve open.

 

Ive wanted the rev thingy too. My HKS SS wont do it. I have been having a slight leak so hopefully after I get the manifolds back on it will boost alittle when reved high. Ive seen videos where s13s are wooshin at a parking lot, stopped. I just love hearing it, is that soo wrong? I dont think its rice.

 

yeah i heard a Supra Turbo making some crazy Blow Off sounds while parked. He did like I said earlier and revved, backed off, revved, etc. Pretty obnoxious, but sounded pretty sweet

 

You just want to make sure that all this 'coolness' doesn't get in the way of the bov doing its job right.

The last thing you want is for the bov to get sucked open too easily and blowing off air that shoulds still be going to your engine to make boost.

 

Of course a setting of lower psi would be safer than a higher psi. Doing it's job correctly would mean stopping the compressor surge, and if it's set too high, it will surge. If it's set too low however, you may just not make full boost. In any case, it does need properly tuned for the right balance.

 

sweet I new Id get some good answers. thanks alot.