Is the 3rd vacuum line necessary?

Tedbuildiy

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Hello all,

So I have recently joined the group of many people who snapped the plastic nipple off of the manifold (goes to DV) on my stock DV, why is it even needed to connect to the manifold ?
Can I not just plug the 3rd line?

Obviously my car is only boosting to 6 PSI (Target : 18)

Just wondering if there is a workaround instead of drilling and tapping a hole in the manifold...
 

Tedbuildiy

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Jan 9, 2020
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I cant tell if you are serious or trolling but yes you need to fix it.

I’m being serious, just want to know to know why the vacuum has to connect,

the only solution I came to was it’s all a closed system
 

JBacon335

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the vacuum is what actuates the bypass valves. it is absolutely necessary if you don't want to kill your turbo(s)
 

Tedbuildiy

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the vacuum is what actuates the bypass valves. it is absolutely necessary if you don't want to kill your turbo(s)
Thanks for clearing that up. Was just reading online why it’s needed.

It wasn’t a troll post just curious to know the science behind it
 
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derekgates

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Thanks for clearing that up. Was just reading online why it’s needed.

It wasn’t a troll post just curious to know the science behind it

That line is what allows the diverters or blow off valve to open up when the throttle body/butterfly valve closes. This allows the excess boost pressure to be released instead of causing 'back pressure' to the turbo and risking the chance of damage (as the extra pressure can cause a reversing of direction on the turbine and eventually cause fatigue on the shaft or fins)...

The 'pulling' of the vacuum in the line is what opens the valves in the diverters or blow off valve.

It is great to learn about this stuff! Hard to tell if someone is serious on the internet. :)
 

Tedbuildiy

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That line is what allows the diverters or blow off valve to open up when the throttle body/butterfly valve closes. This allows the excess boost pressure to be released instead of causing 'back pressure' to the turbo and risking the chance of damage (as the extra pressure can cause a reversing of direction on the turbine and eventually cause fatigue on the shaft or fins)...

The 'pulling' of the vacuum in the line is what opens the valves in the diverters or blow off valve.

It is great to learn about this stuff! Hard to tell if someone is serious on the internet. :)

Hey!

Thanks for that, really helps me under the concept of N54, and what the additional things are 3)

Yeah it’s hard to ask anything nowadays which is annoying but oh well.

Thanks once again.
 
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derekgates

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Tedbuildiy

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Jan 9, 2020
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For sure. Don't hesitate to keep asking questions! These cars are complicated and quite sensitive.

I like how you opened a thread for this question, excited to see others from you.
There’s definitely a few things which I might have problems with in this upcoming weekend (turbo) install.

it’s amazing how finely tuned everything is yet it all works in sync.
 

b4llistic

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EDIT: Thanks your finding and reading my post. Unfortunately, Spoolstreet is no longer a neutral platform where we can have honest discussions on subjects and products freely.
For this reason I have deleted all information I posted on the forums.
 
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ansch

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Sep 23, 2018
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It's an interesting system once you get to know it. The manifold tap is the only place from the factory you can get a boost/ vacuum reference, although you can get an adaptor for the throttle body vacuum port as well these days. The other two vacuum line you mentioned are for each of the boost solenoids, and that vacuum source is driven by the vacuum pump that handles the brake vacuum and exhaust flap as well.
 
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