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post #1 of (permalink) Old 04-23-2008, 12:44 PM Thread Starter
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EGR or no EGR valve

I was talking to my local grease monkey yesterday and we were discussing if a jeep runs better with an EGR valve or without. Iíve had mine disconnected for some time now, his thoughts were that it would run better with it connected..
I have a 83 4.2L no smog, running a Howell TBI set up..
Any opinions?

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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post #2 of (permalink) Old 04-23-2008, 01:00 PM
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If the EGR valve is working correctly, it will run just as well with or without. If not working correctly, i.e., letting too much exhaust gases back into the intake, it will not run well. Your engine is set up to only use the EGR when the temp is right and you are basically at cruise.

The other issue is state smog laws. If they do a visual inspection and see it disconnected, you will have issues.

You have the Howell setup...so for the most part, it's not going to make a lot of difference....except for the amount of toxins your putting into our air.

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post #3 of (permalink) Old 04-23-2008, 01:26 PM
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Try it - I think you'll like it better without.

Exhaust is dead air - no oxygen, not burnable - just like helium would be. When recycled it spaces the burnable molecules farther apart in the chamber, lowering the temperature and reducing NOx formation from heat. (Picture a BBQ with rocks between the charcoal briquettes.)

Since it "takes up space" that's less fuel and air mixture in the chamber, and less heat expansion = less power, less efficiency - but a little less NOx too.

Would you operate better if you ate recycled food? About the same thing!
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post #4 of (permalink) Old 04-23-2008, 01:41 PM
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When my '78 was brand new it had terrible throttle response; at 50 MPH if you fed in a little more throttle it seemed to lose a little speed. A little more throttle and a little less speed, until it was almost wide open. Then it finally started to develop more power and accelerate. It may have actually been producing a little more power in the interim, but it felt like less. Disconnecting the EGR and plugging the hose cured that problem.

The EGR isn't supposed to work that way, and they probably got much better in later years, but as it was, it was very irritating.

EVERYTHING's easy for the guy who doesn't have to do it.
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post #5 of (permalink) Old 04-23-2008, 03:35 PM Thread Starter
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Thx guys just wanted to get any latest info. I have been running W/o it connected, i'll stay that way.

thx again guys..

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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