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masterblaster
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Discussion Starter · #1 · (Edited)
HELP!!!where is the best place for manifold pressure for a wastegate

anyne have any pics of where the best place to tap into manifold pressure is for a greaddy wastegate,we cant get this thing to open at 18psi,also is the blue spring the stocker 18psi one?
 

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suncom3 said:
anyne have any pics of where the best place to tap into manifold pressure is for a greaddy wastegate,we cant get this thing to open at 18psi,also is the blue spring the stocker 18psi one?
Not sure where you came up with that idea. The wastegate should be pressurized from a hole in the IC piping preferrably close to the turbo. Some turbos have a nipple on the side of the compressor housing. This works real well. Make sure you run that directly to the side port on the wastegate. Put a T in this line and run that to the in side on your boost controller. The out of your boost controller goes to the bottom port on the wastegate.

Take care,
Chris.
 

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masterblaster
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Discussion Starter · #8 ·
thank you kindly bud,this helps alot im sure he has it plumed diffrently than this. Now that you say it,this does make alot of sence. I figured manifold pressure would read the same as boost pressure,but im sure this is a much more reliable sourse to tap.
what is the function of the bottom port that runs out of the wastegate to the boost controller?does this just balance the pressure?
 

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suncom3 said:
thank you kindly bud,this helps alot im sure he has it plumed diffrently than this. Now that you say it,this does make alot of sence. I figured manifold pressure would read the same as boost pressure,but im sure this is a much more reliable sourse to tap.
what is the function of the bottom port that runs out of the wastegate to the boost controller?does this just balance the pressure?
Side port pressure helps open wastegate, bottom port pressure helps keep wastegate closed. There's a diaphram inside that causes the pressure to add or take away from the pressure that's already exerted by the spring depending on which port you're applying pressure to.
 

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SpooooL
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although im sure that is the best place, what part of the stock manifold would you most likely tap next? I need to make sure that the wastegate I have isnt defective.
 

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JS4KIKZ said:
although im sure that is the best place, what part of the stock manifold would you most likely tap next? I need to make sure that the wastegate I have isnt defective.
Why would you tap a stock manifold? First of all, there are 3-4 holes coming out of it already that you could use if you wanted. Secondly, you don't hook the stock manifold to a wastegate because pressure is less and when you close the throttle, manifold pressure instantly goes negative.
 

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Misty and Wet
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ChrisBergemann said:
Side port pressure helps open wastegate, bottom port pressure helps keep wastegate closed. There's a diaphram inside that causes the pressure to add or take away from the pressure that's already exerted by the spring depending on which port you're applying pressure to.
Just a couple of questions here, because it doesn't make sense to me:

I've got the UK spec model, which for all intents and purposes is identical to US spec, right?

1. I can see two ports to the back of the actuator, yes. One from the top, one from the bottom (roughly). The one from the top is connected to the pressurised side of the intake, the bottom one to the atmospheric side of the intake (via the VSV). Both appear to be on the same side of the actuator diaphragm, and Toyota's own diagram verifies this.
So I can't see how these ports can play "push-pull" with the diaphragm :dunno:

2. The bottom port can never apply pressure, being on the atmospheric side. It will always be under a degree of vacuum while the engine is running. (that's why it's normally used for crankcase ventilation after all)
As far as I can see, it can only release pressure that has been built up by the other port, or not allow pressure to build up at all (depending on the whims of the VSV)

Since my understanding of the setup differs so much from that of an experienced member here, I wonder: Am I missing something here?

My gut feeling would be to insert a manual boost controller (ball and spring) on the top pipe, thus preventing boost pressure from reaching the actuator in the first place (instead of letting it get there, and then being bled off via the other pipe)
Once the preset setting of the MBC is reached (say 1 bar) then boost pressure would flood the actuator, and it would pile up as the ECU would have instructed the VSV to be closed by then, thus opening the wastegate and stopping further boost rise.
This would help keep the wastegate totally shut for as long as possible, improving boost buildup.

Does this make sense to anyone here?
 

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Sooooooo JDM
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JohnA said:
Just a couple of questions here, because it doesn't make sense to me:

I've got the UK spec model, which for all intents and purposes is identical to US spec, right?

1. I can see two ports to the back of the actuator, yes. One from the top, one from the bottom (roughly). The one from the top is connected to the pressurised side of the intake, the bottom one to the atmospheric side of the intake (via the VSV). Both appear to be on the same side of the actuator diaphragm, and Toyota's own diagram verifies this.
So I can't see how these ports can play "push-pull" with the diaphragm :dunno:

2. The bottom port can never apply pressure, being on the atmospheric side. It will always be under a degree of vacuum while the engine is running. (that's why it's normally used for crankcase ventilation after all)
As far as I can see, it can only release pressure that has been built up by the other port, or not allow pressure to build up at all (depending on the whims of the VSV)

Since my understanding of the setup differs so much from that of an experienced member here, I wonder: Am I missing something here?

My gut feeling would be to insert a manual boost controller (ball and spring) on the top pipe, thus preventing boost pressure from reaching the actuator in the first place (instead of letting it get there, and then being bled off via the other pipe)
Once the preset setting of the MBC is reached (say 1 bar) then boost pressure would flood the actuator, and it would pile up as the ECU would have instructed the VSV to be closed by then, thus opening the wastegate and stopping further boost rise.
This would help keep the wastegate totally shut for as long as possible, improving boost buildup.

Does this make sense to anyone here?
John -
What you missed is the mention of a Greddy external wastegate being used, not the OEM actuator. Chris's explanation was spot on.

FWIW -
Always source your WG/BC pressure from the compressor housing or damn close to it. It's not *as* big a deal on the larger turbos but will cause boost spikes on the "smaller" ones.

Ryan
 

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masterblaster
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Discussion Starter · #18 ·
chris,thanks for you help and explantion on the wg,we will post results soon,im sure it open properly now,it seemed to work well when we took it apart apart and put some antiseize on it,the gate was slamed locked in the internal bushings before we fixed it.
 
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