bov problem plz help

[ajbrain]

hi guys, i got a Greddy type RS bov. its not brand new when i bought it. heres the problem. the bov does not blow off at low psi like 1-2psi. i can hear compressor surge. when i boost to 10psi at high RPM and shift, i can hear compressor surge a bit for 0.5 second then it blows off. i try adjust softer but the RPM will drop down very low sometimes even stall when i shift to neutral and let it go by itself. plz help me out. thank you so much.

s13 redtop max boost at 10psi
stock maf
stock fuel bump
370cc injector
all work find.

[jspaeth]

It is working fine. The BOV shouldn't open from just 1-2 psi.

10 psi, it should open no problem. The diaphragm may be pinched a little or something if it's not opening right away.

[ajbrain]

It is working fine. The BOV shouldn't open from just 1-2 psi.

10 psi, it should open no problem. The diaphragm may be pinched a little or something if it's not opening right away.

but i can hear a little bit flutter for 0.5 second, which is surge. then it blows off. is it OK?

[whitey240]

Is your BOV recirculated?

Do you have a dedicated vacuum line from the throttle body to the BOV?

[ajbrain]

Is your BOV recirculated?

Do you have a dedicated vacuum line from the throttle body to the BOV?

it is not recirculated. i connected two vacuum sources to the bov. one is on and after the throttle body. the other one is the brake vacuum line before the check valve. i think the vacuum sources are strong enough.

[jspaeth]

it is not recirculated. i connected two vacuum sources to the bov. one is on and after the throttle body. the other one is the brake vacuum line before the check valve. i think the vacuum sources are strong enough.

Huh? I am confused....does your BOV have two ports?

Mine has one, and it is connected to the intake manifold.

[ajbrain]

Huh? I am confused....does your BOV have two ports?

Mine has one, and it is connected to the intake manifold.

the bov has one port only. i connect those two sources with a big T before the bov needle.

[jspaeth]

the bov has one port only. i connect those two sources with a big T before the bov needle.

Okay, well that is overkill. One vacuum line from BOV to somewhere on the Intake Manifold.

[segovia]

I had the exact same problem out of box, I tried all vacum sources, and nothing worked, until i ended up cutting/shortening the spring. Both springs actually. It worked great after that, no leaking or surging. I got tired of the rmp drop in shift from not recirculating, so i ended up going back to stock recirc. works great since. Just bought PBM HMIC Kit, i wont be running a bov at all. Type rs is a definite headache though. Good Luck.

[S14DB]

the bov has one port only. i connect those two sources with a big T before the bov needle.

yeah, your BOV should ONLY be hooked up to the Intake manifold to see Vac.

[ajbrain]

I had the exact same problem out of box, I tried all vacum sources, and nothing worked, until i ended up cutting/shortening the spring. Both springs actually. It worked great after that, no leaking or surging. I got tired of the rmp drop in shift from not recirculating, so i ended up going back to stock recirc. works great since. Just bought PBM HMIC Kit, i wont be running a bov at all. Type rs is a definite headache though. Good Luck.

im having headache now lol. the bov now works but not perfect. the only problem is a bit surge without dropping down RPM while shift to neutral. i think the rpm will drop is because the bov, causes leak in the piping, is open when it suppose to be closed. in my opinion, the ECU would detect the throttle is closed maybe the Throttle Position Sensor will send the massage. so when the throttle is closed, it doesnt matter how much metered air blows off. the ECU will switch the engine to the idle mode. if the throttle is closed, no matter how you modify the car, the metered air would not go through the throttle and no fuel would be injected for that much air. so recirculated the bov/dv/etc is preventing the bov/dv/etc from leaking. therefore you dont need to care about the adjustment. it will blow off to the intake between the TB and MAF. correct me if im wrong.

[S14DB]

im having headache now lol. the bov now works but not perfect. the only problem is a bit surge without dropping down RPM while shift to neutral. i think the rpm will drop is because the bov, causes leak in the piping, is open when it suppose to be closed. in my opinion, the ECU would detect the throttle is closed maybe the Throttle Position Sensor will send the massage. so when the throttle is closed, it doesnt matter how much metered air blows off. the ECU will switch the engine to the idle mode. if the throttle is closed, no matter how you modify the car, the metered air would not go through the throttle and no fuel would be injected for that much air. so recirculated the bov/dv/etc is preventing the bov/dv/etc from leaking. therefore you dont need to care about the adjustment. it will blow off to the intake between the TB and MAF. correct me if im wrong.

The factory ECU expects the BOV to be recirculated. If it's not, metered air is dumped that the ECU expects to stay in the system.

[ajbrain]

The factory ECU expects the BOV to be recirculated. If it's not, metered air is dumped that the ECU expects to stay in the system.

got it! thank you. im wondering can a Emanager fix this problem by slight tuned?

[Max_PSi]

Honestly when I was running 10lbs. I never had a problem with idle or driving issues. That was with a basically stock setup though.

You'll run rich between shifts but you shouldn't notice anything.

[jspaeth]

got it! thank you. im wondering can a Emanager fix this problem by slight tuned?

No, it has nothing to do with which computer.

You can solve the problem by running a "blow-through" MAF setup or a MAP setup, both of which would realize air is missing upon blow-off.

[ajbrain]

but where should i put the "blow through" MAF? right after the air filter or after the BOV? i knew a "blow through" setup will help. thank you all you guys.

[S14DB]

No, it has nothing to do with which computer.

You can solve the problem by running a "blow-through" MAF setup or a MAP setup, both of which would realize air is missing upon blow-off.

There are computers that can do decel and idle compensation for BOVs.

Still easier to go back to recirc...

[ajbrain]

There are computers that can do decel and idle compensation for BOVs.

Still easier to go back to recirc...

i had tried recirculation but i clearly heard surge. dont no y. its better to blow off to atmosphere i think. so i want to keep the setup.

[S14DB]

No, it's not on MAF setups. It just makes a cool sound.

Was this when you had that T hooked up?

[ajbrain]

No, it's not on MAF setups. It just makes a cool sound.

Was this when you had that T hooked up?

it was recirculated while had only one vacuum source from the intake manifold.

[Z32TT-R]

i had tried recirculation but i clearly heard surge. dont no y. its better to blow off to atmosphere i think. so i want to keep the setup.


Not neccerarily true, recirc is usually the best way to go especially with an Maf set up.

[Mosaic]

A good BOV install will do 3 things for u.
1) Vent hi pressure surge on throttle close and save turbo inertia.
2) Apply that inertia to precharging the IC, by not remaining open
3) Allow the IC pressure to give you better throttle response and get your turbo back to speed and NOT leak.

A better BOV install will also allow you to have an emergency boost vent upon a spike occuring or Lean boost detected to save your motor.

The best BOV install will do all of the above AND be response/duration tunable with in cabin control to easily switch to super throttle response or moderate street driving depending on street conditions.