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

    • soviet_merlin
      Duncan's V37.......race car?

      By soviet_merlin · Posted

      Thanks for doing that Duncan! Makes you a good person in my books. We don't get kangaroos or wombats here. But we have bats and it's similar. AFAIK it's often the mums with a baby attached that get hit because they drop lower when starting from a tree. If you hit an animal, check on it. https://www.ifaw.org/au/resources/wildlife-rescue-app An app to get the closest wildlife rescue contact.
    • Murray_Calavera
      Jacks that fit under GTR lips that can reach the subframe?

      By Murray_Calavera · Posted

      My dream is also to have a proper hoist, but I don't think it will ever happen. My quickjack is probably as close as I'll ever get, it really is very good though. 
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      Yeah we keep on in the dailies, it is pretty poor how many animals get hit and the driver leaves without checking....have saved a couple of little ones over the years. Bit of a gruesome job though, pouches generally need to be cut open because they are so tight and often the joey doesn't realise mum is gone so they are still locked onto the teat. I checked the modules in front of the DS wheel where an oil cooler should go.... There is the radar unit - that can go for race use) One of the 2 HX water pumps, the silver cylinder. That needs to be kept but might be able to be relocated But the bad news, the big computer mounted vertically in front of the wheel (blocking any potential air exit) is the electric steering computer. That is required until/unless i do a hydraulic steering conversion, and in CAD based modern car design it is not like I can just pop a big unit like that somewhere else (plus the loom would be too short anywhere else too). So, the passenger side is OK to clear out (just use a smaller washer reservoir, potentially elsewhere), but the DS no beuno
    • Duncan
      Chris' Toyota Mark ii JZX110

      By Duncan · Posted

      Well, all the best with the new camry It was interesting to hear about the UK process, it is generally a lot more streamlined here with a shipping agent looking after all the import side (noting the exact final price can still be a surprise.....) and I've used a few different brokers on the japan (or US) side, and never had any trouble with any of them....luck of the draw I guess. You mentioned you didn't get the auction sheet (understandable since you bought it from a dealer, not auction), but I always try and get hold of that because they are pretty thorough. I've imported 2x R grade vehicles over the years and both were fine, repairs in Japan are pretty thorough compared to here in Oz.
    • Duncan
      Jacks that fit under GTR lips that can reach the subframe?

      By Duncan · Posted

      BTW I measured the jack I have, it is 70mm at the saddle but you only have about 700 until it returns to 150mm high at the cylinder so it is good but no magic bullet.
×
×
  • Create New...