Jump to content
SAU Community

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

1400r

By 1400r,
in Engines & Forced Induction

 Share

Recommended Posts

1400r Veteran

1400r

Posted
Posted

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 Mentor

RB30-POWER

Posted
Posted

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 Veteran

1400r

Posted
  • Author
Posted

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 Experienced

R33vit

Posted
Posted
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 Mentor

RB30-POWER

Posted
Posted

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Murray_Calavera
      Quieter performance exhausts (or muffler add-on options)

      By Murray_Calavera · Posted

      Nope.    Grab a varex and turn it down as you get close to home, win win? 
    • f00stx
      Quieter performance exhausts (or muffler add-on options)

      By f00stx · Posted

      So, I've had my V36 for about a month now and have already copped an "excessive exhaust noise" notification from QLD TMR, reported by someone in my local area. It's a twin as per the original, and can have a bit of a throaty note to it when idling cold 😄 and if I do get up it a bit, it can be noisy, but it did pass a roadworthy inspection before sale, so.... ... but in the interest of being a good neighbour, I do want to quieten it down a bit. Is anyone here running a quiet aftermarket cat-back on their V36 or 370Z? And the big, bold question: does an aftermarket cat-back really make much of a performance difference on these cars?
    • GTSBoy
      New kid on the block

      By GTSBoy · Posted

      The wiring diagram for the R33 RB25 is freely available, and is essentially the same same as most other RBs (just with differences as to which pin # does which job). To get the ECU to power up, you just need to provide power to the ECCS relay, and have the other power feeds that come in from the top left of the wiring diagram (wrt the ECU) that give perma power to the fuel pump relay, the ECU itself, etc etc, all connected. When you put power on all these it will just come to life. It's pretty clear from the diagram what needs to happen. Just follow the lines from the 12V + supply stuff in the top left over towards the ECU. I've even posted snips of such diagrams (not for vanilla 25, I think for Neo and 26) to various threads here in the last few months, talking about what it takes to get the fuel pump and FPCM up and going. Search these up and they will help get you started on doing the same with the vanilla 25 diagram. Hell, for all I know, I've done the same with that one in years past and have forgotten.
    • Duncan
      New kid on the block

      By Duncan · Posted

      Yep...so unless someone posts up the answer you will need to probe from the ECU connector to the dash plug with a multi meter in continuity mode to trace the wires.  Note the ECU has multiple - and + (and across different key settings - Battery, IGN and Start) and most likely the power is fed from the connector(s) that is normally near the left hand headlight.
    • Songo
      New kid on the block

      By Songo · Posted

      Thanks Duncan, I am actually just trying to get the Rb turning and running with the RB25DET S2 original loom itself  I am just trying to get it going outside the body and not thinking about the S15 or trying to match anything to the S15 loom at all I am only trying to see if anyone has done this and what pin they found to be the ignition trigger and ECU+/- on the dash connector, that's about it. Thanks  
×
×
  • Create New...