Aftermarket BOV, performance or wank factor

[predator]

I've just been mucking around with a Blitz BOV (atmo).. stocker and blocking them both off last few days to compare.

found that the blitz resulted in a bit of a deadspot after a psht even after adjustment.. way too noisy for my liking.

both blocked off, don't notice much difference, maybe a slight stlight flat spot right after, other than the fairly subtle flutter.. I could run this all the time without too much ill effect i think.. not really worried about an old rb20 turbo lifespan, if it does have any effect on that.

then again mine is not running too much boost atm (12psi).. also auto is a differnet thing when it comes to BOV's.. foot off the accel = psht. none on gear changes.

[Mid_Nite_R33]

Hey all !

I have blocked off my standard bov on my r33 gtst and unpluged the plumback tube from it so it makes a nice fluttering noise, is it ok to be doing that ?

Anyone know which sort of after market blow off valve makes a fluttering noise ?

[LowRollaBoy]

Wow. Cbf reading all the pages.

My points are probably m00t, but on the NVH topic, this is a extract from an s14 Service manual:

Recirc Valve

EC-17 Nissan S14 Service Manual 1994.

"The recirculation valve reduces the noise occuring in the compressor

of the turbocharger during acceleration. This valve recirculates air compressed

downstream of the intercooler to upstream of the copressor using the intake monifold

vacuum that occurs when the throttle chamber is suddenly closed.

The recirculation valve also must not be disassembled or adjusted. For

diagnosis, refer to EC-206

Also another point which probably has been covered, is that with AFM/MAF bovless or atmo bov, has the same effect of running rich between gearchanges. Atmo bov has a harsher effect, but the MAF/AFM does run rich due to exiting reverb comming out.

Most OEM bovs also dont like high boost. Nissan in particular design them with a SMALL recirc hole which presents a small boost leak the more boost you run. Also most oem bovs are designed to recirc, and do open at idle.

The only bov known to not leak is the toyota Mr2/SSQ type bov, which has a reverse piston design! ie: The more boost you make, the harder the bov piston is shut.

m00000t

[czy18e]

steve,

I tried winding it fully tight but it still blows off after 15psi so on the weekend ill try putting a plug in the bov so it doesnt work at all and let you know what happens.

My car runs no afm so it cant be anything to do with the recirculating bov.

The bov is mounted about a foot from the throttle body under the drivers side guard.

[sl33ek]

An old style HKS sequential (not super) BOV will make the fluttering sound after the usual pssht sound. It has a rubber valve, which i think is why this happens but dont quote me on that.

doesnt go off or is very quiet on gear changes under 3000rpm which suits me fine