No boost

[33bomb]

Hi I'm having trouble with my bov. Got it all recirculated but when I put the vacuum line on the bov I get no boost. The previous owner had blocked the bov and had the vacuum line running back to the other lines. Could it be the bov has a big leak? Sorry still new to turbo cars. It's a r33 with a rb25det. Cheers 

[Duncan]

Yes, this is probably the issue. a BOV is literally a big boost leak by design.

It needs a vacuum line to the top of the BOV from after the throttle. If you don't have the same pressure in that vacuum line as the intake, the BOV falls open.

[GTSBoy]

Yeah, wot he ^ sed. The vac line has to be from the plenum.

[33bomb]

1 hour ago, Duncan said:

Yes, this is probably the issue. a BOV is literally a big boost leak by design.

It needs a vacuum line to the top of the BOV from after the throttle. If you don't have the same pressure in that vacuum line as the intake, the BOV falls open.

This is how they'll previous owner had the vacuum line setup for no bov. I reconnected the line circled to bov but get no boost.

[GTSBoy]

That line that runs from the closer T piece and heads to or under the crossover pipe. Is it connected to the crossover pipe nipple there or is it connected to a steel pipe that goes further forward?

[33bomb]

28 minutes ago, GTSBoy said:

That line that runs from the closer T piece and heads to or under the crossover pipe. Is it connected to the crossover pipe nipple there or is it connected to a steel pipe that goes further forward?

It goes to a steel pipe under the crossover pipe further to the canister. Could it possibly be that the person that did it had the boost gauge hooked up the those lines?

[Ben C34]

Anything Is possible

No boost means the car goes slow.  that's why the turbo is there.