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Discussion Starter #1
i have read that some people block off there egr
valve--why

thanks
dave
 

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call me vain, but I did it because it's ugly.
 

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The EGR valve is there as part of the emissions package. It allows a small amount of exhaust gas to enter the combustion chamber. Doing so cools the combustion charge slightly and reduces NOX.

Mike
 

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Certain intake manifiolds do not have the port. Valve will not work so why keep it, just put in the resistors.

 

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So if you remove all the smog stuff, does it still make sense to have the EGR? If you don't have the pipes going to the back of the heads, will the EGR do anything?
 

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I found as many reasons to remove it as to keep it. If you have a cold air intake than why heat up the upper intake with hot dirty exhaust gas, on the other hand it makesit run better and NOX. Search correl.net on subject.
 

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Originally posted by Wolverine:
So if you remove all the smog stuff, does it still make sense to have the EGR? If you don't have the pipes going to the back of the heads, will the EGR do anything?
Yes and Yes.

The pipes going to the back of the heads are from the air pump, not the EGR.
 

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The pipes going to the back of the heads are from the air pump, not the EGR.
I thought that's where the EGR let in the exhaust gases. :confused: I know it's not connected but I figured the EGR popped a solenoid that controlled those pipes.

If it's not, where do they come in? I seem to remember those pipes were also plumbed down to the H-pipe on my donor. But it was 2 years ago that I tore it down so maybe I'm not remembering correctly.
 

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Discussion Starter #13
great info--mine is on the engine but not hooked up with vacuum-so i hooked up the vacuum and the car smokes when i rev it.but the car idels smoother--i have a 92 5.0 ltr with fuel injection-edelbrock aluminum heads--whats up with that??
thanks
dave
 

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Originally posted by Wolverine:
</font><blockquote>quote:</font><hr /> The pipes going to the back of the heads are from the air pump, not the EGR.
I thought that's where the EGR let in the exhaust gases. :confused: I know it's not connected but I figured the EGR popped a solenoid that controlled those pipes.

If it's not, where do they come in? I seem to remember those pipes were also plumbed down to the H-pipe on my donor. But it was 2 years ago that I tore it down so maybe I'm not remembering correctly.
</font>[/QUOTE]The EGR passages are plumbed through the heads and the intake manifold.

Here's a picture of my motor withou the intake manifold on. See the holes in the center of each head between the middle two intake ports? Those are the EGR passages.




Pete
 

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So that must mean there's a port on the intake that lets exhaust gases in, right? I'll have to check that out this weekend. Or am I still completely missing the boat?
 

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The Egr just helps get the engine to temp sooner. Once the engine is there the port is closed untill the engine is cold again. Don't get it confused with the smog pump which injects air into the exhaust path for cat operation and dillution of the exhaust for emissions.

Dan
 

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Originally posted by Wolverine:
So that must mean there's a port on the intake that lets exhaust gases in, right? I'll have to check that out this weekend. Or am I still completely missing the boat?
See the small hole in the top middle of the lower intake - EGR passage.
 

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My understanding of the EGR is that it lets exhaust gas in when the engine does not need the full amount of power the engine would normally create at that RPM under normal air/fuel ratios. If there is too little gas in the mix (air/fuel ratio), then NOX goes through the roof (The combustion temp gets really high, and you start creating NO, which turns to NO2 and will help create smog, as well as rough combustion). The EGR allows an essentially inert gas to be sucked in (only when required) to the cylinder so the air/fuel ratio doesn't get out of whack and combustion temperatures remain lower. At WOT (as an example), EGR is closed, so no exhaust gas gets in. Thus you don't lose power when you want it, only when it's better not to have it.
There are also several different ways EGR gets plumbed. On the modulars, it is sucked straight off the exhaust pipe, into the intake manifold. I'm not sure which valve type is used on the 302's. Ford apparently has had about 5 different designs for this since the 70's.
If you can keep it, use it.
 

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So lets trace this back on more step. That port on the lower intake probably routes back to the EGR valve on the side of the throttle body, right? And that valve is controlled by the EGR solenoid.

Now all I remember is some vacuum lines going to these. What I'm trying to get in my brain is where the exhaust gases for the EGR come from when you take off the smog plumbing.
 

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Gas comes from the exhaust ports in the heads, through the intake manifold to the EGR spacer. When the EGR valve is open, the gas goes into the intake through the EGR spacer.

The vacuum line going from the EGR solenoid to the EGR valve simply opens the EGR valve.

The smog plumbing has absolutely ZERO to do with the EGR system. The smog plumbing you're treferring to is for the air injection system. The EGR and the air injection systems are two completely different unrelated (although they both serve to reduce emissions) and unconnected systems.
 
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