no bov low boost .5 stock bov .7 bar boost?

[1400r]

bypassed my stock bov on my 32 the other day and it made the nice flutter noise but would only hit .5 bar not the normal .7 bar with it hooked up to bypass I stuck a bolt in the vac line leading to the top of the bov. Also when I tried to run the bov as non plumb back it would open and close at idle? once replumbed it was fine again. Any idea did I bypass the stock bov wrong I could make up a plate if that what I need to do my mate cefiro runs no bov at all and it boosts easily to .7

[RB30-POWER]

If you remove the vacuum/boost feed line from the top of the BOV it will leak under boost.

You need that connected to equalize the pressure on both sides of the bov diaphragm.

If not you have boost/positive pressure pushing on the bov piston inside the crossover and no pressure on the other side to eqalize the pressure and keep it closed. Without that it will open and let boost out.

Hence you getting less boost.

Not to sure why your messing with it anyway.

Messing with it will only cost performance at the end of the day.

[1400r]

the vac line seemed to suck when I took it of not blow as it would need to hold the bov closed? however this was only at idle so it may change under load. Im messing with as it seems to be leaking (opening and closing at idle) when I took the plumb back hose off.

[R33vit]

the vac line seemed to suck when I took it of not blow as it would need to hold the bov closed? however this was only at idle so it may change under load. Im messing with as it seems to be leaking (opening and closing at idle) when I took the plumb back hose off.

Under boost there will be positive pressure not vacuum

[RB30-POWER]

They do open under idle as one side has vacuum on it from the plenum (the hose your talking about). This is normal.

The system is designed to do this. Almost all OEM bov fitted cars are designed to recirculate on idle.

When you 0 vacuum or boost, the boost from the plenum line will push on top of the bov and keep it closed because the pressure on top of the bov and in the crossover are equal.

[psybic]

Try a harder spring. Had an after market BOV on old car, didn't open at idle. You could see it clearly shut, didn't leak until i put a soft spring in it being a ricer seeking noise...