would BOV open under boost?

[nismo1003]

I know it's not supposely open , but I hear the BOV blowing sound while driving , it's fully open when it drop back to vaccum. u know what cause that? I have a boost gauge, the higher RPM , the lounder the blow off sound , I did adjust the spring, but it didn't help much. It's a Blitz BOV , i got it new, I don't think it had problem , how can I test if it is working properly? what kind of tools should I use? My o2 sensor gauge (AUTOMETER) move up and down at low RPM around 2000-3500rpm , but once it reach 5000( basically when I reach boost) , my o2 sensor gauge shut off by no reason, what cause that?shut off like no light at all.

[95_240sx]

your gauge will do that when you go full lean or full rich and go off the scale. thats what happens when you buy a cheap A/F ratio gauge, Haltech makes a very nice gauge however.

Rick

[SloS13]

Why would the brand of gauge matter? Arent all narrowband gauges just voltmeters reporting the voltage that the sensor is sending out?

Speaking of A/F gauges, I'm getting this one soon:http://www.innovatemotorsports...98b37

[rco8786]

dude are ya sure it's not your wastegate?

[02_silver_wagon]

I know when I got on my WRX hard. It was the wastegate that made this high pitch fluttering sound. I was pushing 19psi using vf30 internal wastegate and it couldn't handle the pressure.

[d240t2]

What kind of sound is it? If it is a ch-ch-ch-ch-ch...then that is compressor surge and not a blow off valve noise. In that case, your compressor is improperly sized for your setup and that is causing compressor surge. If it is a whoosh sound, then that indeed may be the BOV opening...but it may also be the sound of exhaust going through the wastegate.

[SloS13]

where is your bov getting its vac signal from?

[95_240sx]

Teed off of the FRP Vac line.

Rick

[nismo1003]

maybe my wastegate, ,I can reach to 8 psi, my boost gauge also read at 8 psi . my car just didn't want to go (when it reach boost) , what I am thinking now is that , I am running too rich at high RPM because I am using a 270cc w/ FMU . and the FMU build up the pressure and too much fuel either burning rich or lean, and that's why my o2 sensor gauge is off like 95_240sx siad the scale is off( but isn't it read 0-1v) only ? i read the FSM , the o2 sensor can't go beyound that?. I put the MAF before the compressor sidie ,if my BOV is open under boost . so it can't read accuratly reading . I will try to lift the car up and put in to gear and rev it, and see what's making the noise

[huguetpj]

The autometer gauge will go off the scale if running very lean, but will stay at the last green light if running very rich. Just FYI

[C-Kwik]

Check for a boost leak. Boost leaks can casue two circumstances that can cause a loss of power.

#1, in order to flow more air, the turbo must spool more air. If the wastegate reads manifold pressure, then it will keep the wastegate closed longer to reach full boost. You may have 8 psi at the manifold, but it's possible you have a much higher psi at the compressor.

#2, a boost leak can cause a rich condition. With an FMU, it will be initially much richer than it should, but then as the injectors and fuel pressure maxes out, it will become fairly normal.

Reason #1 would be more likely to cause a loss you can actually feel. A boost leak will sound like a BOV depending on the type of BOV you have.