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R34 - Block Bov = Low Boost

illusiVe

By illusiVe,
in Engines & Forced Induction

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illusiVe Proficient

illusiVe

Posted
Posted (edited)

Hey guys/girls (pfft) ...

anyways I have an R34 GTT and when i block my BOV i get a maximum of 5psi, and it takes longer to build unless its a light LIFT-OFF. (which is why i wanted to remove it, better response).

But i want my full 10-12psi (stock turbo).

I've blocked my lines from the bov, and the boost controller im using is a Turbosmart dual-stage (amazing, never had 1 spike issue with it)

anyway, i just want my full boost without my BOV in use.

help :P

post-12759-1158564655.jpg

Edited by illusiVe
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https://www.sau.com.au/forums/topic/134817-r34-block-bov-low-boost/
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Cubes Grand Master

Cubes

Posted
Posted

lol... Your not blocking off the bov.

By blocking off the boost feed you are allowing it to open easily as there is no pressure on the opposite of the diaphragm, Pressure on the opposite side of the diaphragm equalises the pressure and holds the bov shut under boost.

mad082 Grand Master

mad082

Posted
Posted

the best way to block it off is to remove it and put a plate over the top of the hole. then you need to block the return line.

and by blocking it off you won't get better respnse. in fact on gear changes you will have MUCH more lag as the air in the cooler piping hits the closed butterfly, turns around and heads back towards the turbo, and hits the compressor, slowing it down.

the bov lets the air out and keeps the air flowing in the 1 direction.

and at 12psi you wouldn't be losing any boost pressure. if you are want a bit more response you can block up the recirculation hole in the bov. just take the bov off, countersink a hole so that the head of the screw will be flush with the bov. then put a wood screw in.

mad082 Grand Master

mad082

Posted
Posted (edited)

but you aren't getting the same response. you are only getting 5psi. try the same thing without a boost controller, just off the wastegate (so its 5psi) and see which is better. and you said in your first post that it takes longer to build boost unless it is only light throttle lift off.

yes it takes time to vent, but since your current setup is holding the bov open the air is just flowing straight out. but once you step on the gas again and it buils up enough pressure to open the bov you would lose power, as the turbo keeps working harder and harder, but the boost doesn't rise.

Edited by mad082
illusiVe Proficient

illusiVe

Posted
  • Author
Posted (edited)

last time i take friends advice for 'removing a bov'

my poor turbo :P

so if i do something like this (as i understand it from your post)

will remove bov physically and car will run 12 psi with no leakage :(?

not shown in the pic, i'd also have to block the original hose from the throttle body/intake area thingie :(?

post-12759-1158584172.jpg

Edited by illusiVe
Cubes Grand Master

Cubes

Posted
Posted

You only need to throw a plate on the cross over pipe then bolt the bov back over the top of it. Be sure to use gaskets.

But...... Don't fiddle.. Just leave it.

The stock bov is there for a couple of reasons, improve part throttle drivability and to aid turbo life.

Kinks Grand Master

Kinks

Posted
Posted

in illusive's post, just cut a bit of sheet metal to size and block it where the yellow label is. Don't worry about disconnecting any of the other stuff or plugging anything else.

If you block it at the flange then no air will recirculate, no matter what the diaphragm does. Leave everything else connected so you have no air leaks, and presto.. blocked BOV and it looks stock :)

illusiVe Proficient

illusiVe

Posted
  • Author
Posted

thanks for confirmation, yer last thing u want to do is put a piece of metal in your engine by someone just saying 'do this' and being unsure.

when everyone was basically saying the same thing, i gave it a shot and it works awesumz.

my noBov mod is proudly sponsored by 1 wasted can of coke.

shonen Grand Master

shonen

Posted
Posted

can of coke ????

hahahaha oh man I wanna see a pic of that !! :)

Anyways best way to block off the bov is to take out the black rubber hosing that connects the bov to the return pipe, go to the local hardware and buy 3/4' (from memory) rubber stoppers for chair legs haha and attach to the bov and the return pipe and do up the clamps and your done.....

I only done this to check if the bov was faulty as I seemed to be loosing boost somewhere...and I was right too I was losing boost but it wasnt from the bov....dont recommend leaving it blocked off for extended periods of time though.

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