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Topic: To EGR or not to EGR...

in Forum: C3 Fuel, Emission Control, and Exhaust Systems

To EGR or not to EGR...

Posted: 6/22/06 11:06am Message 1 of 8
Former Member
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United Kingdom
Joined: 6/20/2006
Posts: 21
Vette(s): 1975 Coupe, owned since October 2005. Stock apart from minor engine mods, cam, carb and headers to dual exhaust.

Ok so what do you guys think?

I have no need of emmision control and cant see that piping exhaust back through the engine can be any good. Yes I know it reduces engine temps but why would anyone put waste products back through the engine.....




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To EGR or not to EGR...

Posted: 6/22/06 1:03pm Message 2 of 8
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Former Member
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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
When I bought my '78 the smog pump was missing anyway, so when I installed an Edelbrock intake I removed the EGR and its related components. In my case the car ran better and it cleaned up the appearance under the hood.


To EGR or not to EGR...

Posted: 6/22/06 2:34pm Message 3 of 8
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Canada
Joined: 10/31/2005
Posts: 3
Vette(s): 1974,4 speed, small block,teal blue L88 hood, definitely not stock

I believe that an EGR valves only come on at idle at all other times the're closed. So a properly operating EGR valve shouldn't have any effect on performance.

if you have more than a mild camshaft  valve overlap does the same thing as an egr valve,  look at a camshaft profile, the intake valve will open before the piston reaches TDC and the exhaust valve closes after TDC, generally the wilder the cam the more the overlap.

So If you have a wild cam, the EGR isn't needed since the camshaft itself is doing the job and the engine isn't generating a lot of vacuum to suck exhaust gassesthrough the EGR .So as gunslinger pointed out, removing it does clean up the engine compartment.

 

 




To EGR or not to EGR...

Posted: 6/22/06 7:51pm Message 4 of 8
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CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
Posts: 6424
Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Actually, the EGR is closed at idle, then opens as throttle increases, and closes again at wide open.

It send exhaust gas into the cylinder.  The exhaust has already been burned, and can't burn again, so for all purposes, it's inert.

Inert gas won't change percentage of air to fuel.  It's not air and not fuel.  As a result it slows down combustion due to diluting the air fuel mix, with out changing it's percentage.  This makes it burn cooler.  Why?  at about 2500 deg F. the engine starts to ping and knock, and produces a lot of NOx.

There is not enough heat a idle to cause a NOx problem, and at wide open the engine burns richer.  Richer mixtures burn cooler, so the EGR is not needed.

Try plugging the hose to the EGR and going for a drive.  If it does not ping, knock, or run hot, you can remove it.   Provided the car is over 25 years old.  25 or less and the EPA doesn't like any one removing them.  Sort of illegal.  Over 25 years old has no federal restrictions.  Some states still complain.




To EGR or not to EGR...

Posted: 6/23/06 1:05am Message 5 of 8
Former Member
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United Kingdom
Joined: 6/20/2006
Posts: 21
Vette(s): 1975 Coupe, owned since October 2005. Stock apart from minor engine mods, cam, carb and headers to dual exhaust.

Im in the UK so its not a problem to remove it. If I remove it then it will decrease my mpg....more fuel has to enter cylinder to fill space previously occupied by the 'inert' gas...

Will plug the hose and see what happens. Thanks for the replies.




To EGR or not to EGR...

Posted: 6/24/06 10:30am Message 6 of 8
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Klamath Falls, OR - USA
Joined: 2/1/2006
Posts: 1059
Vette(s): 74 coupe 4 speed 350, 54K actual miles, all original; paint, interior, engine, split bumper. #'s match. 2nd owner, no stress cracks.
Does anybody make a "aftermarket plate" that would cover the hole in the intake manifold where the EGR use to go?  THANKS



Steve, Lifetime Member #129

74 coupe 4 speed 350, 54K actual miles,
all original; paint, interior, engine,
split  bumper. #'s match. 2nd owner, no stress cracks.

To EGR or not to EGR...

Posted: 6/24/06 5:44pm Message 7 of 8
Former Member
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Australia
Joined: 5/6/2004
Posts: 535
Vette(s): 71 Coupe Black on Black
Why not just buy a complete performance manifold from the likes of Edelbrock or similar without the EGR port? You'd end up with better performance and another plate you wouldn't have to seal.


To EGR or not to EGR...

Posted: 6/24/06 6:11pm Message 8 of 8
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BINGHAMTON, NY - USA
Joined: 7/19/2003
Posts: 3808
Vette(s): ......
Thats what I did ,put a non EGR Edelbrock Performer manifold on looks good ,no ugly EGR Ron 7838892.7583333333


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in Forum: C3 Fuel, Emission Control, and Exhaust Systems


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