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Boost Solenoid RB25DET


240Z_Master

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Okay, I'm pretty sure I am missing my boost solenoid (it's funny how solenoid is spelt, but oh well).

 

My question... I have a GReddy Profec B-Spec II which came with a boost solenoid, is there a way I can use that signal from the GReddy unit to send to the ECU?

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I may be wrong but the solenoid you are seeing is probably a signal for the computer to know when an overbooste condition exists to cut fuel and not to control boost. The vacuum signal to the waste gate actuator controls boost. It is not the same solenoid you have fro the GReddy Profec B-Spec II. Anyway you can post the wiring diagram?

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I may be wrong but the solenoid you are seeing is probably a signal for the computer to know when an overbooste condition exists to cut fuel and not to control boost. The vacuum signal to the waste gate actuator controls boost. It is not the same solenoid you have fro the GReddy Profec B-Spec II. Anyway you can post the wiring diagram?

 

I think stony is right on that one

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It does say booste control on the diagram. But I'm still pretty sure Its a sensor for controlling boost with a fuel cut. if you overboost it will cut fuel and booste will drop. that is why alot of guys put the boost cut defencer's in. This tricks the computer into thinking you are at a lower booste then you are and not cutting fuel. I had an rb25 when i was in japan and it was a manually controlled boost system that had LINES plumbed directly off the intake and this is what controlled the wastegate actuator.

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If this is the solenoid I'm thinking of, it is in line with a T off of the actuator boost line, then it recirculates back into the air inlet to the turbo. This is used to "spike" the boost. It keeps boost off of the actuator until a certain point so the boost comes up quicker. When using an aftermarket boost controller, this solenoid goes into the trash or it will cause extremely erratic boost. The "gain" feature on modern boost controlers does the same thing, it holds off boost from the actuator/wastegate until a predetermined point is reached. You turn up the gain until the boost overshoots a little, then turn it back a little.

 

Boost acts on the actuator as soon as it sees even 1psi. Say at max rpm, the wastegate valve needs to be open 10mm to hold the boost at 10psi. That means that it starts to open at much lower boost. This, in effect, bleeds off exhaust pressure on the turbine wheel, making boost come up much slower. The solenoid is normally open, allowing boost to bleed back into the inlet pipe, lowering the signal on the actuator. When the boost reaches a point set by Nissan, the valve closes, giving the actuator a much later opening, and bringing boost up much quicker.

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If this is the solenoid I'm thinking of' date=' it is in line with a T off of the actuator boost line, then it recirculates back into the air inlet to the turbo. This is used to "spike" the boost. It keeps boost off of the actuator until a certain point so the boost comes up quicker. When using an aftermarket boost controller, this solenoid goes into the trash or it will cause extremely erratic boost. The "gain" feature on modern boost controlers does the same thing, it holds off boost from the actuator/wastegate until a predetermined point is reached. You turn up the gain until the boost overshoots a little, then turn it back a little.

 

Boost acts on the actuator as soon as it sees even 1psi. Say at max rpm, the wastegate valve needs to be open 10mm to hold the boost at 10psi. That means that it starts to open at much lower boost. This, in effect, bleeds off exhaust pressure on the turbine wheel, making boost come up much slower. The solenoid is normally open, allowing boost to bleed back into the inlet pipe, lowering the signal on the actuator. When the boost reaches a point set by Nissan, the valve closes, giving the actuator a much later opening, and bringing boost up much quicker.[/quote']

 

Wow, thats why you are the man, thanks a bunch.

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