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B.o.v And Boost Control

stagpower

By stagpower,
in Four Door Family & Wagoneers

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Ska Grand Master

Ska

Posted
Posted

Yeah I have a GFB Stealth and when I have it set to full atmo, it's nearly loud enough to wake the dead :nyaanyaa: I love it, but it just screams to cops, "DEFECT ME!" so only turn it to atmo now and again, mainly have it set to plumback :domokun:

Oh and not only can you use the SAFC/SAFC2, but also using a Power-FC fixes this, basically any form of aftermarket ECU/piggy back ECU that tunes fuel should be able to fix it up.

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DECIM8 Grand Master

DECIM8

Posted
Posted

From my infomation a BOV increases the rate at which you hit boost and enables it to come on easier if that makes any sence...

Plumb back is best (im gettin a Stealth FX) and might turn it to atmo when i get a S AFC Neo

ssshonky Grand Master

ssshonky

Posted
Posted

my simplistic take on how Atmo BOVs upset some systems is basically the engine management computer goes

HEY.. WTF did all that air go ? conk .. stall ...

( I did say simplistic )

Yeah BOVS improve shift times due to when the butterfly valve in the throttle body closes ( on liftoff for shifts ) it prevents a big wad of trapped air bouncing back down the intake tract..

Please note that I do not proclaim to be an expert at this. just what I recall from previous discussions

Stinky Rooster Grand Master

Stinky Rooster

Posted
Posted
my simplistic take on how Atmo BOVs upset some systems is basically the engine management computer goes

HEY.. WTF did all that air go ? conk .. stall ...

( I did say simplistic )

:D

Its funny because its true!

Somebody get this man a pork pie hat with a press card in the band

You need to start writing tech articles with eloquence like that

ssshonky Grand Master

ssshonky

Posted
Posted

haa.. at work I got told to work on my writing style for technical write ups because they were " too personal "

:D

Its funny because its true!

Somebody get this man a pork pie hat with a press card in the band

You need to start writing tech articles with eloquence like that

  • 2 years later...
stagman Community Regular

stagman

Posted
Posted

Hmmm, well heres a ancient thread revival. But is one that seemed most relevant in discussion to B.O.V's that i could find.

The talk in this topic seems to be mostly about the series 1 stagea, and from what i understand while a plumback is best suited to either engine, a atmo will work with some form of tuning.

Because my car is the series 2, Will my nistune be able to counter the loss of air the atmo will give or would it be better to just go plumback and not worry. (Yes this is rice( i would like a little sound though), yes i know it doesnt help much with the car, but Its my car and ill do what i want haha :P.)

QWK32 Veteran

QWK32

Posted
Posted
Hmmm, well heres a ancient thread revival. But is one that seemed most relevant in discussion to B.O.V's that i could find.

The talk in this topic seems to be mostly about the series 1 stagea, and from what i understand while a plumback is best suited to either engine, a atmo will work with some form of tuning.

Because my car is the series 2, Will my nistune be able to counter the loss of air the atmo will give or would it be better to just go plumback and not worry. (Yes this is rice( i would like a little sound though), yes i know it doesnt help much with the car, but Its my car and ill do what i want haha :P.)

i haven't seen anywhere in nistune where you can control the decelerating air mixture the way the SAFC does. unless it can be controlled from the main fuel map you'd still get the stalling i'd say.

stagman Community Regular

stagman

Posted
Posted
i haven't seen anywhere in nistune where you can control the decelerating air mixture the way the SAFC does. unless it can be controlled from the main fuel map you'd still get the stalling i'd say.

Ah okay interesting. So that leaves options with a plumback, or just don't waste the money?

ssshonky Grand Master

ssshonky

Posted
Posted

I would just leave the factory BOV in place. The other reason why I am not a fan of ATMO ( ie louder ) BOV's in auto's ( I presume your Stag is Auto? ) is that the auto seems to make the BOV go off at werid times. I guess the same is true with Manuals ( ie rev, back off , flutterz )

pixel8r Mentor

pixel8r

Posted
Posted

I fail to see how a BOV will help with performance at all.

Basically, while building pressure, there will be absolutely no difference between a plumbback or atmo bov. since both will stay fully closed until the pressure exceeds their preset threshold (which wont happen until pretty much as soon as the butterfly closes again).

The difference between them only occurs when you LIFT your foot off the pedal, so there's no way it can make boost build faster or slower. The 2nd difference is after you lift your foot - either the excess air from in the intake will vent to atmosphere or it will end up back in your intake. If its back in the intake then this would assist in response as well, since once you hit the pedal again it doesn't have to suck more air in, its already there ready to go...

I cant see any of that making a huge difference to performance but in any case the way I see it - the atmo bov could only be worse, not better for performance.

The only way performance could increase is because you need some form of ecu/tuning to get the atmo one to work - but I'd argue if you put the same ecu+tuning with the plumbback you'd get the same benefit.

Hope that makes sense...happy for someone to provide a counter-argument since I'm only talking theory here...

iamhe77 Grand Master

iamhe77

Posted
Posted
Basically, while building pressure, there will be absolutely no difference between a plumbback or atmo bov. since both will stay fully closed until the pressure exceeds their preset threshold (which wont happen until pretty much as soon as the butterfly closes again).

If you are talking aftermarket BOV's, then yes, I agree.

OEM Nissan BOV? Different. How so? Well it has a small hole that is constantly bleeding air and bypassing the actual valve which aftermarket units do not have AFAIK.

You cannot just take the tubing off an M35 BOV because it is constantly leaking air which will cause terrible fuel economy and stalling.

I have been told that all Nissan BOV's have this "feature"

atomaly Rising Star

atomaly

Posted
Posted

i have a series 2 RS4-s with a blitz atmo BOV. it came like that when i bought it.. and i'm pretty sure there's no form of non-standard tuning on the car

i dont get any stalling whatsoever! :rolleyes: my fuel economy is not AWESOME tho. i'll get a PFC eventually.

_Ryan_ Grand Master

_Ryan_

Posted
Posted

Any MAF car will have some degree of issue with an atmo BOV.

A MAP sensor based ECU is the best way around this if you MUST keep it.

The best option? remove the fkn ghey BOV, and if you are running stupid boost fit a factory GTR BOV.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
If you are talking aftermarket BOV's, then yes, I agree.

OEM Nissan BOV? Different. How so? Well it has a small hole that is constantly bleeding air and bypassing the actual valve which aftermarket units do not have AFAIK.

I have been told that all Nissan BOV's have this "feature"

There are two ways around this. You can tap this small hole and put a screw in it. Mark the screw when it bottoms and then wind it out and cut it off at that point and cut a slot with a hacksaw. Then screw it back in making sure that its flush (nothing protruding).

The other way is to get a GTR bov. They don't have the hole but they have a different diameter return hose so you will have to make some adaptor.

pyro-ns Community Regular

pyro-ns

Posted
Posted

does anyone know what pressure level the factory bov is good for (in a s2 steagea)? the vast majority of time we're getting flutter... i would have thought it'd be a consistent woosh with a proper plumback setup?

QWK32 Veteran

QWK32

Posted
Posted
does anyone know what pressure level the factory bov is good for (in a s2 steagea)? the vast majority of time we're getting flutter... i would have thought it'd be a consistent woosh with a proper plumback setup?

Mines blowing open at 1bar, so I've had to block it off until I get a new higher rated aftermarket plumb back. If your keen Josh let me know an I'll swap BOV's with you, yours might be stuffed and it's not opening properly so you get the flutter. Mine is working fine, just not good enough for my setup.

Ska Grand Master

Ska

Posted
Posted

I had a Stealth GFB bov on my stag and it was as loud as hell. It was great, I could adjust it for plubback or atmo venting. Didnt make a lick of difference to power. Going through some of the old docs I have laying around my HDD I found these and thought they might be useful:

Blow_Off_Valves.pdf Discharge.pdf

_Ryan_ Grand Master

_Ryan_

Posted
Posted
Mines blowing open at 1bar, so I've had to block it off until I get a new higher rated aftermarket plumb back. If your keen Josh let me know an I'll swap BOV's with you, yours might be stuffed and it's not opening properly so you get the flutter. Mine is working fine, just not good enough for my setup.

Tried a GTR BOV?

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