B.O.V. not going PSSHH

[wobbly]

im a bit confused as to why only my car that i have come across does this, when im parked in the garage and give it some revs turbo doesnt spool so doesnt build up pressure to be released out bov, only when engine is under a load (moving), but utube clips, people are in parking lots and they work for them, i thort it was because i had a factory bov, but got a hks one today and same thing
anyone know why???

[gt4dude]

theres 2 main kinds of bov
push and pull



example hks ssqv is a pull type, boost keeps it closed, vacuum pulls it open, theres no way for boost to escape like example you cant push a door that says pull lol. so the hks doesn't need to be adjustable, the diaphragm is just preset to an optimum boost level, any less than said level and its doing fk all harm to your turbo to even bother blowing off.

now to the traditional push type, this is adjustable by a bolt and locknut preload on the spring which operates a push type, the air pushes against the piston to escape, boost from the feed equalises pressure to keep it closed, the differential between boost and vacuum allows the boost to push the piston up revealing the exit port, when you loosen the preload bolt, the less boost it will take to push open that port, and when you tighten the more boost it will take.
you adjust it to find a medium where 1. high boost levels dont push it open and leak boost and 2 its not done up so tight that boost can barely move it at all and it cant let out enough air causing compressor surge...


i was just about to delete all that and say go look up the difference between push and pull type bovs, but i wrote it anyways *sigh* prob doesn't even make any sense either lol its 5am

what i was getting at with this is the ones you saw in their videos were probably set loosely

[gt4dude]

from what i can tell, the factory gt4 and also your gtt bovs are the pull type, but they are set alot looser than the hks ones, hks ones retain more air in the cooler piping for better boost response when you get back on the throttle after a quick gear change.

if you want more bov sounds with less load you could use your factory one and just vent to atmo with it, but its far too leaky for my liking, it was only ever designed to be plumbed back in.

blowoff sounds crap when theres not enough load anyways i dont see why you would want to do it, it just sounds like a pathetic exhale.

atmo bov is fad has passed anyways, heres how you do it these days , it's all about the tutututu

[FST4RD]

im a bit confused as to why only my car that i have come across does this, when im parked in the garage and give it some revs turbo doesnt spool so doesnt build up pressure to be released out bov, only when engine is under a load (moving), but utube clips, people are in parking lots and they work for them, i thort it was because i had a factory bov, but got a hks one today and same thing
anyone know why???

thort

Seriously though I have had cars that haven't done this, depends on the BOV your running.[/b]

[mjrstar]

, depends on the BOV your running.[/b]

Unlikely, if the engine is not building boost when stationary there will be no noise. some cars will build a small amount of boost without load.

ie something with a small framed turbo with lightweight internals.

[l1ttle_d3vil]

when driving mine I can easily hear mine venting anything over 2500rpm. when stationery I need to rev it to about 4000 - 4500rpm before I can hear it vent. Can feel air venting on lower revs when its stationery though, just a bit harder to hear it for some reason.

[wobbly]

ok here is my example, this not my car, but exactly the same, my car did not do this when it had factory bov, but this one seems to. am confused...
http://www.youtube.com/watch?v=A2AQmytsBJU

[andrewgreen1000]

Here is a video of a complete stocker that doesn't seem to "PSSSSH".
So probably B.O.V type?

http://www.youtube.com/watch?v=V2eWnV2ATA8&NR=1

[MR2SIK]

, depends on the BOV your running.[/b]

Unlikely, if the engine is not building boost when stationary there will be no noise. some cars will build a small amount of boost without load.

ie something with a small framed turbo with lightweight internals.

like most Nissans, all the sick street driftaz manage to do it

launch control will get you to do what you want

[cogent]

just gonna leave this here
http://www.youtube.com/watch?v=gUuTb0M9YQI

[base]

is it boosting at all might sound like it is but does it have the extra power?

[h8wrxs]

just gonna leave this here
http://www.youtube.com/watch?v=gUuTb0M9YQI

why does it make that noise before??? is that from running no bov?

[Akane]

It's running no BOV, which tests on mr2oc.com shows you hold boost better between gear shifts as it keeps the intercooler and intercooler pipes pressurised between 3-5psi for a few seconds even tho the blades has stalled and regain "lift" again (everytime you hear it go Do do do do it has stalled to a very low pressure rating which then in turn unstalls the blades and builds pressure up again... rinse and repeat), if you run a BOV you vent all pressure and it has to be build pressure up again.

I have come up with a somewhat uneducated conclusion that the rotational inertia of the turbo is great enough at such high RPM that you only lose a tiny bit more rotational speed if you run no BOV compared to running a BOV. The turbo fins are not too heavy but if you multiply it to 90k RPM, there's some serious inertia there.

I'm talking about race applications that lifting the throttle for only half a second and stomping on the throttle again. Not your average "drag that WRX of au" gearshifts.

I would so run my turbo without a BOV but can't really afford the monthly rebuilds........

[gt4dude]

Dooose it

[Soiled]

I ran my car for quite awhile without a BOV when I first installed the turbo, it definatly didn't hold boost better between shifts. It nearly completely stopped my turbo each gear and had to build boost again. Having the BOV made a world of difference.

Was only running low boost at the time so maybe that makes a difference also.