stock R33 BOV

[RB BOY]

hi guys

i was just wonderin whether or not with the stock BOV on the R33 you can pull the plumb back hose off and make it atmospheric. does this cause any problems??? and does it work better, not better, works the same, just makes a louder noise. what?? can u please email me to tell me, thanks alot.

email is: [email protected]

[rev210]

it can't work better, it doesn't work better, it will cause problems.

Leave the factory one alone it's a very good BOV.

[G0DF4Th3R]

i tried it

stalled all the time, wouldnt even idle

[LBR33]

yes you will have problems the car will stall easily, wont hold idle and the turbo can shatter cuz the air isnt flowing back to the turbo

[Ronin 09]

Godfather - I'm guessing the stalling is for two reasons -

1. runs rich because AFM will read higher than actual air into engine when BOV vents;

2. stock BOV leaks on boost (see thread titled "BOV mod" or something similar...) causing excessively rich.

I have a rice-boy-spec vent to atmosphere - It idles OK, stalls about once a week - After market management will fix that.

lbfalcon - don't know what you are talking about mate... you will not shatter your turbo because there is no airflow back to the turbo. I think you have confused having no BOV, the air feeding back to the turbo through the compressor will have long term damaging effects on the blades and bearings.

[G0DF4Th3R]

Ronin - i think i know what ure referring too... seems familiar.. something abt placing a small screw on one of the small holes at the bottom of the bov.. will look it up

[rev210]

the stock bov does not leak on boost, it leaks a tiny little bit of air around 0 pressure to make the transition on and off boost smoother.

The BOV mod is nothing special it does nothing for power. I tried it and I must say leaving it alone is the best idea.

[JasonO]

Ronin - i think i know what ure referring too... seems familiar.. something abt placing a small screw on one of the small holes at the bottom of the bov.. will look it up

Don't use a screw, use the little black lid bit out of the top of an old style BIC Biro. Does the same job, fits the hole like it's made for it, and can be removed without having buggered up the OEM BOV

[otto]

I wonder if a stock bov with the screw mod vented to atmo would idle better seeing as it wouldnt be leaking and causing afr probs?? Just a thaught..

I know a completly stock one will contiuously stall when vented to atmo.

My stokies got the little mod might vent it to atmo and see how it goes just for curiositys sake, however i dont know why youde want it venting to atmo considering all the negative sides to it, and if your into the noise the stockie bov plumbed is pretty loud when youve got a pod filter, well mine is anyway.

[nitemare5]

the screw won't help your cause with it venting to atmo, that little hole just does exactly what rev210 says, smoothes out the transition from off-on boost. blocking it just stops that from smoothing out.

[Anquetil]

I wonder if a stock bov with the screw mod vented to atmo would idle better seeing as it wouldnt be leaking and causing afr probs?? Just a thaught..

In my case it made my idle rougher and caused minor surges, but this was plumbed back...

I originally had an older style Turbosmart Type II BOV which caused a rough idle and surging.

I went back to the factory BOV and the rough idle and surging went away completely, however as already mentioned it just wasnt as snappy.

So I did the screw mod, there was a noticable difference, but it idled a little rough and was surging again but not as bad.

[rev210]

shane,

your problem is there is an air leak somewhere.

[otto]

the screw won't help your cause with it venting to atmo, that little hole just does exactly what rev210 says, smoothes out the transition from off-on boost. blocking it just stops that from smoothing out.

Ok, wouldn't that little leak be just like if you had a leak in your manifold (when the stock bov is venting to atmo of course) and a leak in your manifold would cause rough/no ide wouldn't it?

I just recon this little leak is why the stock bov doesnt idle when vented to atmo and most other aftermarket ones do because they dont have that little leak.

Dont get me wrong im all for the stockie being plumbed back and dont know why anyone would want it venting to atmo. My mate tried to tell me once that venting to atmo was better cause the hot already compressed air went back infront of the turbo again with a plumb back, i dont recon this is really true cause when air drops in pressure it drops in temp aswell so theoretically it would go back at the same temp as it came in, accept of course that the intercooler has already taken some heat out so maybe the air would go back at a lower temp than it came in? would this make plumbacks better??

Also i can see some good in blocking off the hole, yes it may stop the smoothing out as may people have said thats why nissan put it there but surly the turbo would not be working as hard to make the same boost?

[otto]

the stock bov does not leak on boost, it leaks a tiny little bit of air around 0 pressure to make the transition on and off boost smoother.

The BOV mod is nothing special it does nothing for power. I tried it and I must say leaving it alone is the best idea.

How does air leak at zero pressure?? i always thaught you needed a difference in pressure to get movment. anyhow i know for a fact it does leak under pressure cause i blew on it and like alot of other peolpe found out when they tried this it bypassed air (leaked), aparrently a human being can generate almost 2 psi with there mouth i found the harder i blew the more it leaked. this would mean it leaks under pressure wouldnt it?

[rev210]

I'm pretty sure the leak occurs at a point where the piston part is just starting to move. The hole becomes blocked as the piston moves past a little groove due to the manifold pressure feed on the top.

[rev210]

you also might want to look at where the leaking air comes out and where it leaks to. Consider that the feed at the top of the BOV has a pressure difference thanks to the plenum air.

[Ska]

I can say that yes the stock bov vents on spool when I had it venting to atmosphere, I rigged up a really dodgy bent piece of metal which then bent out to vent the air, but I found that having something blocking it almost stopped the stalling on idle, I found this out by holding my hand over where the air vents and it idled smooth as silk, once I unblocked it, BAM rough idle?

I have no friggin idea what this means and am not a mechanic, I will be taking pics later on before I reattach the plumb back just to prove how DODGY it was , sick of just before boost hearing a constant whoosh from the bov and thinking of all that power being lost

[fresh]

just curious, i am thinking of getting a GFB stealth FX valve, do these cause the problems u guys r describing or should they bolt on fine ??