Question on waste gate hook up, new turbo

[DeepBusch69]

My old Turbonetics had a reference port near the end of the outlet for the waste reference line.  I bought a Garrett and there is no such port.  How should I hook this up?   

 

[LegitDuner]

My reference line was hooked to the manifold. That was so the blow off valve was responding to what the motor was actually seeing not what the turbo was putting out. You could have 15 at the turbo housing but the motor could only actually be seeing 12. Is your boost gauge teed off that compressor fitting or is it referencing manifold pressure?

There's definitely two schools of thought about this. I would ask your tuner what he prefers.

 

[ChasingSand]

I second connecting it to the manifold. I blocked off my port on the compressor housing. 

 

[Bobalos]

X3. Just do some cautious laps and see what the boost does.  

 

[John@Outfront]

My reference line was hooked to the manifold. That was so the blow off valve was responding to what the motor was actually seeing not what the turbo was putting out. You could have 15 at the turbo housing but the motor could only actually be seeing 12. Is your boost gauge teed off that compressor fitting or is it referencing manifold pressure?

There's definitely two schools of thought about this. I would ask your tuner what he prefers.

Referencing the wastegate off the manifold is a poor idea. If you have the issue you mentioned then your intercooler is too small.  Drill and tap the housing in the same place. We do this daily. There are also other benefits by having the WG referenced off the turbo. Boost controllers like turbo reference better than intake too

 

[Okie]

I am glad I came across your post DB69. I am currently staring at my new turbo build and was considering moving my reference port to a different place this time, closer to the manifold. I had never heard or seen people doing it different than the turbo compressor, though. I will explore John's comment on boost controllers now, and re-think my decision. I have just recently been researching (articles and you tube videos) how electronic boost controllers actually work, and found out it is way more involved than I thought. John, can you provide details on your post about this subject, or share links to how the controller benefits from actual turbo boost at the compressor? DB69, we will have to share our final "outcomes" on these at our spring dune gathering. It will be good to dune with you again.

 

[John@Outfront]

I have install hundred of boost controllers and none will show a schematic of referencing the intake as source of boost. IMO there are other benifits. When decelerating intake goes to extreme vacuum but the turbos port is extreme high. Perhaps for a moment even higher than your desired boost (that’s also why we have blow off valves). But think about the diaphragm in the wastegate. I think it’s designed for pressure only, so if it’s ported to the intake it sees extreme differentials. I don’t like the idea my WG diaphragm is getting sucked tight against the piston inside the wastegate. Perhaps violently from 30inHg to 20+psi of boost perhaps multiple times in seconds that’s just the extremes, now think about partial throttle. Intake is still in vacuum whereas the turbo could have a few pounds of boost. The wastegate would respond to opening easier than the manifold as I stab the throttle   

 

[John@Outfront]

Any where from turbo to throttle body would work but if you have an intercooler- any where from the turbo to inlet side of intercooler. So this could also include tapping off the piping to the intercooler or the inlet tank of the intercooler as pressure is really all the same in those three areas ( turbo housing, pipe, intercooler intake tank)

 

[Okie]

Perfect explanation about how it affects the internals of the wastegate. I hadn't considered vacuum! I plan on putting the reference port just before the intercooler. DeepBusch69, what controller are you using?