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Vacuum Line on TB, What for??

  • Thread starter Thread starter AnthonyR23
  • Start date Start date Sep 25, 2009

AnthonyR23

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Sep 8, 2006
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Sep 25, 2009
#1
  • Sep 25, 2009
  • #1
Hey so on my 347, with Trick Flow top end, with powermax 2030 cam, I am looking to replace my 65mm TB, Cold Air Intake kit and 70mm Mass Air Meter said to be cal. for 30lb injectors which I have for a 75mm Accufab TB, 4 inch anderson power pipe, and a velocity PMAS MAF cal. for 30lb injectors.

So first thing I am looking to get is the Throttle Body, It says the Race version of the throttle body has the 4 inch opening so I am thinking I want to go with that version, but still want to run the 75mm EGR Spacer, while keeping the EGR system functional rather than switching to a blank spacer. They offer the regular EGR spacers from accufab that are 75mm, just wondering if I will run into a problem using the 75mm race throttle body. Only difference is that it doesn't have that Vacuum Line on the TB.

Just wondering if this will cause me any headaches. Any opinions about this? Thanks!
 

ID89GT

10 Year Member
May 26, 2008
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49
Spokane Valley, WA
Sep 25, 2009
#2
  • Sep 25, 2009
  • #2
That is for the pcv system, recirculates blow by gases back into the intake to be reused.
 

AnthonyR23

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Sep 25, 2009
#3
  • Sep 25, 2009
  • #3
Well if I want to retain the PCV system, couldn't I just have the PCV system connected to one of the other manifold vacuum sources? With a vacuum T connector for example??
 

liljoe07

5 Year Member
Feb 18, 2009
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Cartersville,Ga
Sep 25, 2009
#4
  • Sep 25, 2009
  • #4
Posted via Mobile Device

The throttle body hose is the fresh Air intake tract of the PCV system. If you don't run it, you apply vacuum to the crankcase, and wind up with oil in the intake manifold. The Throttle line is to make sure the crankcase gases have a way to circulate.

You can mount a fitting on the Air duct tubing, and connect it to the filler neck tube. Just can't vent the crankcase by pulling air from in front of the MAF sensor.
 

AnthonyR23

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Sep 25, 2009
#5
  • Sep 25, 2009
  • #5
So I just had the tb vacuum line hooked up to the oil filler neck tube, so like your saying, then I could just hook up a tube on the power pipe that would do the same thing, right before the tb, but after the mass air meter.

So for the PCV system itself, and the PCV valve, it is just hooked up to manifold vacuum, which is correct right?? Assuming the Valve keeps only the vapours from escaping to the manifold.

So if I do that then do you think I should be okay with the 75mm race version of accufab's throttle body's with the 75mm egr spacer.
 

liljoe07

5 Year Member
Feb 18, 2009
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Cartersville,Ga
Sep 25, 2009
#6
  • Sep 25, 2009
  • #6
AnthonyR23 said:
1So I just had the tb vacuum line hooked up to the oil filler neck tube, so like your saying, then I could just hook up a tube on the power pipe that would do the same thing, right before the tb, but after the mass air meter.

2So for the PCV system itself, and the PCV valve, it is just hooked up to manifold vacuum, which is correct right?? Assuming the Valve keeps only the vapours from escaping to the manifold.

3So if I do that then do you think I should be okay with the 75mm race version of accufab's throttle body's with the 75mm egr spacer.
Click to expand...

1- Yep sure would.

2- Manifold Vacuum is what pulls the Crankcase pressure out. The PCV valve lets air only flow one way.

3- Yes.

 
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