How does the iab's really work?

I have heard it stays closed until 5700rpm then it opens up to let more air in.

I also heard from this well known ecu chipper/ tech that the iab's are really open all the time unless you are running a p72 ecu, because the ecu(p72) actually closes the iab's until it hit 5700 rpm were it "reopens" the iab valves.

The tech said if you open up a gs-r intake manifold you'll see that the iab's are not closed, but open.(i never tried it yet though...I'm a noob)

Any idea?

 

They default to the open position. The ECU has to use the solenoid and vacuum reservoir box to keep them closed by operating on the IAB diaphram on the side of the manifold.

 

When you start the car, vacuum is applied and the IAB actuator closes the butterflies. You can watch this happen.

 

so this means that the iab closes whenever the engine is on but will reopen only if the right ecu reopens it at 5700rpm then?

thanks for the info guys

 

Where is the IAB sensor located on the manifold?? Im trying to hook up some lines to my ecu but dont know where the sensor is located at and how it looks like.. Is it under the manifold or something??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 562daybid &raquo;</TD></TR><TR><TD CLASS="quote">Where is the IAB sensor located on the manifold?? Im trying to hook up some lines to my ecu but dont know where the sensor is located at and how it looks like.. Is it under the manifold or something??</TD></TR></TABLE>

The IAB sensor is loacted on the vacuum log in between the lower part of the manifold and the cylinder head. Kinda tucked in right where the manifold makes it's curve up.

IAB's stay closed until 5750, when they open it gives the incoming air the shortest possible and most direct way into the cylinder head. The reason for the two different runner lengths, is more torque at lower revs and a flatter torque curve.

 

so let say for example, if i was running an ecu that did not support iab's would it be to my benefit to enable the iab's or vice versa and why? and if so how would i go about doing that? is there a sensor or vacuum line that i need to disconnect?
also someone once told me to zip tie the diaphram open, what would this gain or effect?
TIA

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 562daybid &raquo;</TD></TR><TR><TD CLASS="quote">Where is the IAB sensor located on the manifold?? Im trying to hook up some lines to my ecu but dont know where the sensor is located at and how it looks like.. Is it under the manifold or something??</TD></TR></TABLE>

It is not a sensor, as it sends no feedback to the ECU. It is just a blind solenoid.

The solenoid is part 6.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by polishedturd &raquo;</TD></TR><TR><TD CLASS="quote">so let say for example, if i was running an ecu that did not support iab's would it be to my benefit to enable the iab's or vice versa and why? and if so how would i go about doing that? is there a sensor or vacuum line that i need to disconnect?
also someone once told me to zip tie the diaphram open, what would this gain or effect?
TIA </TD></TR></TABLE>

You can custom wire an RPM activated switch to control the IAB.

 

and to disconnect it? or should i bother because the ecu doesnt support it anyway?
what would be pros and cons of doing this? i think the answer would clear up alot of questions for people.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dogginator &raquo;</TD></TR><TR><TD CLASS="quote">

It is not a sensor, as it sends no feedback to the ECU. It is just a blind solenoid.

The solenoid is part 6.


</TD></TR></TABLE>
so where wouuld you wire it from in order for the IAB to work into the ecu?? I know for a civic its pin A26 but I dont know where to wire it from the sensor..