IAC Valve + boost Leak?

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Roblu98

Member

Oct 9, 2007

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16

East Fallowfield, PA

Mar 25, 2009

#1

• Mar 25, 2009

• #1

I am trying to track down a boost leak. Has anyone had any issues with there IAC valve leaking boost? I am think about putting a check valve inline with a IAC valve or putting iac into the discharge side of the supercharger . (like the Procharger set up) What one do think would be better. Thanks fo the help!

 

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Roblu98

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Oct 9, 2007

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East Fallowfield, PA

Mar 27, 2009

#2

• Mar 27, 2009

• #2

Anyone

 

SaleenGT2001

Well-Known Member

Jul 18, 2005

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Four Oaks NC

Mar 27, 2009

#3

• Mar 27, 2009

• #3

wouldnt a check valve cut off all air flow to the IAC????

i've never heard of an IAC causing a boost leak.

 

Flghtmstr1

Member

Mar 31, 2005

572

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Springfield, PA

Mar 28, 2009

#4

• Mar 28, 2009

• #4

I've never heard of it either. It doesn't make sense if you think about it, because the IAC is pulling air from the intake, not from the outside. Even if the IAC "leaked" backwards, it would be dumping air back into the intake, which doesn't matter at all because that air would just find its way back into the engine.

More common boost leaks trouble spots are: vacuum lines that have blown off, intake gaskets, head gaskets, loose silicone couplers in the intake tract, etc.

 

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TonyG

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Apr 12, 2002

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Owings Mills, MD

Mar 28, 2009

#5

• Mar 28, 2009

• #5

I've always been suspicious of that little black cap on the IAC, which is suppose to be a vent. I would like to know more about how/when it vents.

 

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Roblu98

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Oct 9, 2007

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East Fallowfield, PA

Mar 28, 2009

#6

• Mar 28, 2009

• #6

Flghtmstr1 said:

I've never heard of it either. It doesn't make sense if you think about it, because the IAC is pulling air from the intake, not from the outside. Even if the IAC "leaked" backwards, it would be dumping air back into the intake, which doesn't matter at all because that air would just find its way back into the engine.

More common boost leaks trouble spots are: vacuum lines that have blown off, intake gaskets, head gaskets, loose silicone couplers in the intake tract, etc.

Click to expand...

Well it would matter if it dump air to the intake because it would be bleeding boost off. I think i am going to move it to the discharge side of the blower. I will keep everyone posted on how I make out. Thanks for the help!

 

SaleenGT2001

Well-Known Member

Jul 18, 2005

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Four Oaks NC

Mar 29, 2009

#7

• Mar 29, 2009

• #7

Roblu98 said:

Well it would matter if it dump air to the intake because it would be bleeding boost off. I think i am going to move it to the discharge side of the blower.

I will keep everyone posted on how I make out. Thanks for the help!

Click to expand...

the boost would still be going to the intake.....how would that bleed boost off?

 

Flghtmstr1

Member

Mar 31, 2005

572

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Springfield, PA

Mar 30, 2009

#8

• Mar 30, 2009

• #8

I think there is some confusion here because we don't know how your setup currently is. I have a PD supercharger, so the IAC is under vacuum only, just like stock. With a centrifugal supercharger, wouldn't the IAC be pulling air from the inlet tube after the supercharger (which is under boost)? If so, it wouldn't matter whether it leaked backwards or not since it would be dumping into the already compressed air in the inlet. If your supercharger kit pulls IAC air from a non-compressed source of air, then I could see the possibility of a boost leak.

 

bhuff30

Founding Member

Dec 11, 2001

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129

Olathe KS

Mar 30, 2009

#9

• Mar 30, 2009

• #9

I seriously doubt the IAC could cause a boost leak in any configuration. First of all, at WOT, the IAC valve should be closed, which means no matter where it tries to draw the air from doesn't matter because no air can pass through the valve.

How do you know there is a boost leak in the first place? Does the engine fall on it's face when you start getting into boost? Again, look for the common things, like vacuum hoses that popped off and intake gaskets.

 

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Roblu98

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Oct 9, 2007

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East Fallowfield, PA

Mar 30, 2009

#10

• Mar 30, 2009

• #10

My IAC Valve is connected to my power pipe (Intake side of the supercharger). If my IAC Valve is leaking a WOT it would leak boost into the power pipe. Which I dont know if it is leaking because I dont know how to pressure test intake of the motor. If i move it to the discharge side of the supercharger I would not have to worry about it leaking because both sides of IAC valve would be under pressure. I am trying to find if i have a boost leak because I am only seeing 11# of boost and I have a 2.87" pulley on a Vortech SQ. That seems low to me with that small of pulley.