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Intake manifold Emissions questions

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Old Apr 13, 2009 | 03:11 PM
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Default Intake manifold Emissions questions

I know I know, if it ain't broke, don't fix it. I'm just more curious more than anything. I'm trying to experiment with re routing some vacuum lines and making the most simple intake. Just a bare bones type of thing.
I've got some questions though...

1)
is the air regulator actually needed?
All it does is high idle to warm the motor up faster, right?

2)
Does the Pcv line that comes from the Valve cover need vacuum?
I know a lot of people just put those little filter things on there and call it even, but I'm wondering if there would be any gain to re-routing it to the manifold so it has vacuum. Would it need a check valve like the lower assembly has?

3)
The IACV isn't needed to idle, right?
The motor idles on its own and the IACV just compensates for added load, like the AC compressor cycling, or the power steering pump. I've seen guys disable, and/or remove the IACV and still power steering. The motor would bog down when you turned but it never died. The catch is, they never had a/c. Would the compressor cycling on and off create that much extra load?
Would you be able to compensate for not having an IACV but upping the idle a little bit? Which is my next qustion. I was told the only way to adjust the idle is by adjusting the IACV. Is that the only way? Other than just keeping the throttle plate open, is there any other way to adjust the idle?



Thanks for the assistance!
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Old Apr 13, 2009 | 09:58 PM
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any one?
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Old Apr 14, 2009 | 02:24 PM
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Originally Posted by Empire
1)
is the air regulator actually needed?
All it does is high idle to warm the motor up faster, right?

2)
Does the Pcv line that comes from the Valve cover need vacuum?
I know a lot of people just put those little filter things on there and call it even, but I'm wondering if there would be any gain to re-routing it to the manifold so it has vacuum. Would it need a check valve like the lower assembly has?

3)
The IACV isn't needed to idle, right?
The motor idles on its own and the IACV just compensates for added load, like the AC compressor cycling, or the power steering pump. I've seen guys disable, and/or remove the IACV and still power steering. The motor would bog down when you turned but it never died. The catch is, they never had a/c. Would the compressor cycling on and off create that much extra load?
Would you be able to compensate for not having an IACV but upping the idle a little bit? Which is my next qustion. I was told the only way to adjust the idle is by adjusting the IACV. Is that the only way? Other than just keeping the throttle plate open, is there any other way to adjust the idle?


So, after tinkering around some and figuring out how some things work, I think I've answered most of my questions.

1) No, the air reg isn't needed. All it does is let more air into the manifold to warm the engine up quicker. It doesn't effect performance or anything like that to have or not have it. You could technically gut it out and use it as a source or vacuum if you wanted.

2) it doesn't need vacuum and shouldn't get vacuum. It does however need filtered air, that's why it taps off of the intake piping. It doesn't need metered air, just filtered. so the only thing you can really do with it is put a little filter on it and call it even.

3) The IACV does control idle. It also allows for idle. When the throttle plate is closed, the only way air gets into the manifold for idle is through this valve. Simply put, the IACV has a small hole for "base" idle, then the valve just opens to add more as needed. So the people that had completely removed this got their idle by keeping the throttle plate open a little bit. Unless I'm missing something... which is quite possible...
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Old Apr 16, 2009 | 06:47 PM
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Originally Posted by Empire



2) it doesn't need vacuum and shouldn't get vacuum. It does however need filtered air, that's why it taps off of the intake piping. It doesn't need metered air, just filtered. so the only thing you can really do with it is put a little filter on it and call it even.
you got # 2 backwards. Its hook to a vac/intake source so that the bypass/blow by air can be sucked out the block. the PCV releases the pressure from the block and head. some people unhook it and put a filter on.

#1 not sure what u mean by air regulator?
#3 if u N/A just keep it, it makes life easier.

Last edited by KnightDrifter; Apr 16, 2009 at 06:49 PM.
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Old Apr 17, 2009 | 08:48 AM
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Originally Posted by KnightDrifter
you got # 2 backwards. Its hook to a vac/intake source so that the bypass/blow by air can be sucked out the block. the PCV releases the pressure from the block and head. some people unhook it and put a filter on.

#1 not sure what u mean by air regulator?
#3 if u N/A just keep it, it makes life easier.
k... I see what you're sayin about the PCV...

the air regulator is that thing right next to the IACV... taps off of the same hard line... hard to explain without a picture... I'll see if I can find one somewhere...

and yeah, I don't see why removing it would really be much gain...
you said if I'm staying NA... what would you do for boost? just curious...
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