Boost Solenoid

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POWLO

Guest
What does this little gadget do exactly, i can't figure it out.

thanx =o)
 
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AJ4

Guest
in a nutshell... under normal driving conditions it is closed, and restricts airflow to the wastegate actuator so you have more boost. If there is a fault with the car and the engine runs into 'safe mode', the solenoid opens and allows full manifold pressure at the wastegate to drop the boost. Not a lot though, as standard boost is 0.65 bar and safe mode is 0.5 bar :roll: so its pretty pointless.

A good easy mod is to drill a hole in the side of the solenoid so it bleeds off more air ( and hence gives you higher boost ). I bit like a bleed valve, but this method seems to be a bit more stable.



When you add a boost controller, it uses this solenoid ( or one that comes with it ) to control boost pressure more acurately by pulsing the solenoid on and off to control the airflow.
 

ex-gtir

Member
sorry but the solenoid is open for factory boost 0.7bar and when it goes to safe mode is shut and lets the car run actuator pressure 0.5 bar
it a pwm bleed solenoid the ecu can vary voltage to it and it works against a spring of known pondage (spelling)
i should know i make boost mods with these
 
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AJ4

Guest
Sorry, my explanation was overly simplified, but I thought it not really a good idea to mention pulse width modulation to someone who didn't even know what a boost solenoid was ;) :lol: :lol:
 

Fast Guy

Moderators
Staff member
AJ4 said:
If there is a fault with the car and the engine runs into 'safe mode', the solenoid opens and allows full manifold pressure at the wastegate to drop the boost.
I think he was correcting you on that Ross, a higher pressure at the wastegate will make the turbo produce more boost :wink:
 
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AJ4

Guest
no it won't, the wastegate is pressure operated, the more boost it sees the more it opens and bypasses exhaust gas, lowering the boost. <think of leaving the boost hose off accidently and running at full boost ;), likewise, a bleed valve works by bleeding off pressure to the actuator so less pressure at the actuator = more boost :D >

In effect your tricking the turbo into thinking it is running less boost than it is, by feeding less of the boost pressure back to the actuator, so it keeps on spinning up.
 

Fast Guy

Moderators
Staff member
Yep, my mistake I'm working arseaboutface :oops:

OK, the correction lol is that mike says the solenoid shuts, you say it opens :wink:

I thought the solenoid valve was permanently bleeding 0.2bar off to give a normal 0.7bar and in safe mode it shuts, stopping the bleed and reducing it to 0.5bar :?:
 
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AJ4

Guest
yep, thats correct. Depends on whether you mean the solenoid is open to atmosphere ( ie, bleeding pressure off ) or open to the actuator ( ie, allowing full boost to reach it ), your explanation is technically better though, I was wrong.. ;)

:D:D:D
 

geoff pine

Well-Known Member
right so does this mean with a hiteq boost loop im running .9 bar not 1bar :oops: would make my rolling road read out at .9 bar not 1bar or have i got it wrong yet again . :oops: :roll:
 
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