Exhaust recirculating valve

[grskinner]

Saw here where someone suggested blocking these off for better performance.

Has any one else done this?

How?

What are the pros and cons?

Thanks

[naru]

You heard wrong.

Leave it alone.You will lose performance slightly.

[Sapper 157]

Depends on who you talk to... what engine is it for? If it's an EA81, get rid of it. It's pointless and after 30+ years most of them, if original, don't work and aren't worth replacing. The pros would be one less thing cluttering up the engine compartment, and decreased vacuum leaks, and all the cons are purely theoretical as far as I can see. Supposedly your engine will run a little hotter around the valves, but I'm not sure how accurate that is.

If it's an EA82... I'm not sure what the advantages or disadvantages would be.

[El Presidente]

Opinions vary about this, but I've never heard a logical arguments as to why an egr system HELPs these engines. I've heard plenty of warnings, but nothing that was backed up. I certainly welcome a good explanation.

 

I've disabled or removed several egrs from several ea82's and other makes and models over the years. I typically notice a slightly better top end and a better idle if it was faulty. Disabling it is easiest, just unplug the egr valve and plug the vacuum that goes to the solenoid. Done. You can also completely remove the system by blocking off the egr port on the intake with a custom steel plate and replacing the egr solenoid with a 35ohm 10watt resistor. Looks cleaner and functions the same as disabling it, your choice.

 

Pros for pulling egr:

-Cleaner intake and combustion chamber from less carbon from the exhaust getting into the engine. (My main reason for doing this)

-Slightly better top end power (butt dyno)

-Looks better

 

Cons:

-slightly higher combustion temps, never heard of, or had any problems from this.

-May not pass emissions in your state/area. In Washington all you need is a half functioning cat and no CEL to pass in the areas or cities that require it.

[naru]

You could not have looked very hard for those logical argruments..

 

The EGR lowers combustion chamber pressures and temperatures.

Your present ignition system is optimized for EGR operation.

With EGR removed you now have too much ignition advance at cruise.(pinging,engine stress etc.)

Now,I suppose you are going to say "but i didn`t hear any pinging after removing the egr".

That just means your hearing is bad or the timing was not advanced enough in the first place,

Back off the timing and now you do not have enough advance in non cruise sitiuations.

 

No loss at all IF the ignition advance curve is suitably modified.

How many people do that?

 

Then there is the matter of engine pumping losses.

Without EGR the engine expends energy pumping air it does not need.

You will suffer a small MPG decrease because of increased energy expended.

EGR and pumping losses http://www.autospeed.com/cms/article.html?&title=EGR-Comeback&A=112612

 

There is no power whatsoever to be gained by removing the EGR.

Maybe 1lb weight savings.

[El Presidente]

Naru, your making some assumptions about me, but that's ok. I know how to time an engine and my hearing is good. I'm also aware that pinging, especially higher rpm, is not always audible. I've taken apart a bunch of these engines (while working as an auto machinist and later as a hobby) without an egr and only seen a cleaner combustion chamber, with no damage from detonation or pinging.

 

Do you know of anyone or heard of any problems from removing the egr on an ea82 from first hand experiences? I have yet to hear one.

 

I can see how advance mechanisms incorporate or compensate for the egr, but really..how much timing differences are we really talking about? Do you know? 1°?.. 15°? -Not being a smart xss, just curious.

 

Considering egrs are put on vehicles primarily for emissions, the link to pumping losses is valid but seems very overrated. This is considering other engines of the day (including the ea82 mpfi) and newer didn't/don't have them. Not all of course. Can you by any chance show how much of a difference in pumping losses an egr makes on an ea82?

 

After reading what you said about ignition timing curves, it seems increasing the combustion pressure and timing on a 30 year old engine would feel like a gain in power because it's compensating for worn rings.

 

I know you've been on the board a while, so I'm hoping you can answer these questions. Lol I'd be surprised if an egr weighs a pound, but we can round up