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

    • GTSBoy
      My BMW 335i

      By GTSBoy · Posted

      Maybe also really stiffly sprung track cars. Get the inside wheel up in a corner and all the fun stops. Also me sometimes (rarely) when I have to stand on the brake to convince the diff to drive the wheel that is still on the ground when I'm trying to diagonally get over severe driveway entrance, etc.
    • Duncan
      R33 Fuel Pump & Brakes after alarm swap

      By Duncan · Posted

      I feel like I'm missing something. You had an authorised installer come out and install a new alarm. Post install the car doesn't start, and you aren't getting the installer back to fix what they did wrong?
    • Kapr
      RB20DE NEO smallbox clutch.

      By Kapr · Posted

      So either way it is gearbox out and look what is wrong?  I know about the input shaft bearing. Even before swap/new clutch the it sounded exactly like this: So is that inout shaft bearing or the other was installed backwards?  And can some please tell me the part number for that input shaft bearing? The gearbox is small box from R34 N/A and number is FS5W71C. Thank you  
    • Kinkstaah
      My BMW 335i

      By Kinkstaah · Posted

      I am yet to see anyone ever regret a quaife or helical. ...other than drifting/skidpan duties. I kind of want to upgrade my factory helical with a Quaife (but really it's not ultimately that different, and is a MASSIVE UNDERTAKING), that's how good the hype is about them, that I want to try them 'just to see'  
    • GTSBoy
      Unpeeling the Orange

      By GTSBoy · Posted

      D2 and Ksport are essentially the same thing and basically just generic Taiwanese manufacture. Better than ChinaBay crap, but... not top shelf. Öhlins have got to be some of the best dampers around, so likely to be a good option. It's going to get to the point though where I suggest you buy from Oz. We have at least 2x excellent options here. If I were you though, I'd be talking to KW about doing something for the R33. There's bugger all difference between that and the 32. In GTR land, anyway.
×
×
  • Create New...