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R.I.P Dennis Jarvis
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Discussion Starter · #1 ·
Currently I have the wastegate and a vacuum line from the turbo connected to my wastegate sol. When you install a g-valve what do you do with the vacuum line running to the turbo?
 

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Do you have a haynes or chiltons repair manual and look at the vacuum diagram. I know for my car, the turbo vac line is optional. But mine is an 89 t2
 

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R.I.P Dennis Jarvis
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Discussion Starter · #3 ·
See what I mean?
 

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You want to install the G-valve in place of the solenoid. On the '88 2.2 T1 (and the 2.5 T1) the pressure (yes, PRESSURE) line to the actuator is constant (when the turbo is boosting the pressure is going to the actuator without being diverted or blocked) and the solenoid vents the appropriate amount of pressure to control the actuator to maintain the proper boost pressures. Turbo 2 engines do it a different way.
 

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R.I.P Dennis Jarvis
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Discussion Starter · #5 ·
Explains why I never could get my g-valve to work. I just pluged the one comming from the turbo!
 

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Put it before the t on your vac lines
 

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Here is an explanation of turbo bleeds compared to G-Valve I wrote many years ago when I was very active in the turbo dodge scene.

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2.2 / 2.5 Liter Engine Turbo Bleeds

#1 Bleed
A bleed is when the air system has an alternate route to let air escape so that the device being controlled (wastegate) will see less pressure. This will make the wastegate open fully at say 10 PSI instead of 7 PSI. Most of you do a bleed combined with the stock solenoid bleed.

#2 Stock Solenoid Bleed
The stock wastegate control system uses the solenoid to create a bleed. The solenoid opens and closes real fast at different rates (duty cycles) to create more and less bleed on the wastegate. The more often the solenoid is open, the more it bleeds, and the less often the wastegate is open, allowing more boost. If the solenoid is open less, the wastegate will see more air pressure, and be further opened, allowing less boost. The solenoid is controlled by the computer by the feedback it gets from the MAP sensor. If the solenoid is stuck closed not allowing a bleed, or if you connect the vacuum line directly to the wastegate, the boost level should be about 5 PSI max. So if you only get 5 PSI your solenoid is likely shot.

#3 G-Valve
A G-Valve does not let air escape but holds it back from the wastegate until a certain pressure is obtained. Then the valve opens allowing the air pressure to open the wastegate. There is a bleed which is not the major controlling factor on the wastegate side of the G-Valve that allows for the wastegate to close again after the pressure closes the G-Valve. If this very small bleed was not on the wastegate side, the wastegate would remain open and you could boost no more than 5 PSI. So maybe some of you consider this small bleed on the wastegate side a bleed that controls the boost? The vacuum line never sees this small bleed.

The 1st 2 systems (bleed and stock solenoid bleed) always puts some pressure on the wastegate allowing it to open a little at low boost. This is what causes some of the turbo lag. A G-Valve does not let the wastegate open at all until is sees the set pressure so it has less lag.

Note: Much of this comes from the work of Gus Mahon

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I was very fortunate to have me Gus at Gary Donovan's back then.
 

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R.I.P Dennis Jarvis
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Discussion Starter · #8 · (Edited)
Since my boost is generated by the turbo (refer to my vacuum diagram), I assume this is the best way to plumb mine. (Blue second pic)



This is the other method I've seen used. However it does not reflect a connection to the turbo.
(first pic)
 

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a line needs to be coming from the outlet of the turbo, or the intake (works better off the intake) go to your grainger valve, then connect to your wastegate actuator. Easy Peasy.
 

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R.I.P Dennis Jarvis
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Discussion Starter · #10 ·
One good thing about the first option (mot using the turbo boost) is that it's closed looped and I don't have to worry about contamination.

However with the turbo vac line plugged and using a vacuum connection to the intake, what is generating the boost. The turbo is disconnected.

As in this 87 vacuum line the turbo is not connect so what is creating the boost?
 

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No, when boost hits in your intake it'll push the grainger open. The reason it's better to use the intake is because there is usually more boost in the lines than in the intake. Sooner too which will make the valve open sooner and possibly not reach as much boost as it's full potential. So you'll get quicker spoolup with it connected to the intake and be able to crank the boost higher without stretching the spring provided you have the supporting mods to run more boost.
 

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One good thing about the first option (mot using the turbo boost) is that it's closed looped and I don't have to worry about contamination.

However with the turbo vac line plugged and using a vacuum connection to the intake, what is generating the boost. The turbo is disconnected.

As in this 87 vacuum line the turbo is not connect so what is creating the boost?
The turbo is creating the boost.....

Forget about the vacuum nipple on the turbo. The turbo outlet is pressurizing the entire intake system, so any vacuum port is seeing boost. You want to plumb the grainger from the intake so you don't get the waste gate opening until the entire system is pressurized. Your first picture is ideal, the second one, not so much.
 

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Since my boost is generated by the turbo (refer to my vacuum diagram), I assume this is the best way to plumb mine. (Blue second pic)



This is the other method I've seen used. However it does not reflect a connection to the turbo.
(first pic)
87 T2 also
would it be ok to hook up a vacuum block on that nipple with the manual boost controller on the back of the intake, or should the mbc be the only thing on that nipple and the vacuum block be connected to the vacuum port on the front of the intake that controlls the pcv and fuel pressure regulator?

i am going to be using the type of bleed g-valve in the faq section it has one nipple and one hole and connects to a T in the vacuum line
 

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nevermind it is the one that lookes like picture one

but the question is the same should i hook up the mbc alone or can i hook it up to the vacuum block?
 
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no prob.its so much better this way.i have a few lines that need to be removed but i dont have any caps to plug the ones not being used
 
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