Egr delete

[Mcdunn516]

To delete the egr is it just as simple as blocking off the egr?  I have no cats and no emissions here. Would it be beneficial to keep the egr or not needed?

Mike

[markolson]

Personally, I like EGR systems.  They give you  better fuel economy, lower NOx emissions and reduce the chances of part throttle detonation.  I understand EGR in modern EFI systems a lot better than the ones in these old trucks, but I believe they give the same benefits.  So I always keep the EGR systems in my vehicles.

That said, the engine bay looks a lot cleaner without it...

[VileZambonie]

EGR system will not yield you fuel economy boosts. If you want to bypass the system, simply disconnect and plug the vacuum hose going to the EGR. If you are removing it for looks then a bypass plate is needed.

[markolson]

I respectfully disagree that it doesn't increase fuel economy.  If exhaust gas is displacing air and fuel, it is increasing fuel economy.  How much it improves it is a matter of debate, however.  You may have a hard time noticing the difference in real life, especially of your engine is not in perfect tune.

If you can play with your distributor timing curves, it can have an even bigger effect.  The air/fuel/exhaust mixture can tolerate more advance without detonation, giving you more power from less fuel.  That is a lot easier to do with a modern EFI system, however.

Thanks for telling us how to do the delete.  It's good to know.

[VileZambonie]

That must be a neat trick. An inert gas in an internal combustion engine increases fuel economy how? I'm looking forward to hearing how this works.

The EGR is designed to reduce Oxides of Nitrogen it is not designed to increase fuel mileage.

[markolson]

The inert gas replaces some of the air-fuel mixture, effectively reducing the displacement of the motor, reducing the amount of fuel consumed.  This is in addition to the effect of reducing the combustion temps.   And you can get more power out of less fuel by being able to increase the spark advance without detonation, giving you more cylinder pressure at the optimum crank angle.

The fuel economy you get from this gets a lot better in EFI systems where you have complete control over spark timing.  I am not sure how well this works with a distributor, but you can get more fuel economy out of engines with EGR systems.

[454Man]

The problem you run into is these egr systems where designed to work with pre- ethanol gas. fact- ethanol/ gas running engine will hotter due to the loss in btu. The engine runs lean due to the loss of btu. Combine this with that egr and you get all sorts of detonation. Only way to make it work correctly is to run a more rich air/ fuel mixture. But then there goes you mpg benefits

What's under the hood??? If you have to ask maybe we shouldn't race...

[Irish_Alley]

to add to what they said, (cause i have to put my into everything) but the egr job is to reduces NOx levels by cooling the combustion chamber temps. exceed 2500° F atmospheric nitrogen begins to react with oxygen during combustion this produces NOx. NOx is bad for emissions, so the egr circulates a small portion of gas to the combustion chamber to "cool" it keeping the temp below 2500°. it makes sense on paper that if you replace air/fuel with exhaust gas you will reduce the amount that goes into the cylinder(and this maybe true for a low working load engine, but egrs doing that will rob the engine of power and thus requiring more gas to do the same job. another tidbit of info some engines nowadays like the 3.6 Chrysler Pentastar engine require no egr. if it saves gas why wouldnt they put it on the engine

[markolson]

I'll admit that EGR systems main benefit is reduced NOx emissions.  I can be convinced that it doesn't do much, if anything, for fuel economy in a carbureted system.  I believe that it definitely can improve fuel economy in an EFI system.

I also believe that it is possible to hit similar design targets with non-EGR equipped EFI motors, too.

We are all entitled to our opinions.

I hope no one is offended by this thread.   

[Irish_Alley]

yes we all have our opinions, and i voice mine whenever i can lol. but with the government enforcing lower emissions and increase mpgs and the technology that engineers are facing to have better mpgs wouldn't you think if it help any even if its .5 added to a tank. that Chrysler would of kept it on the 3.6?

[markolson]

Engine design is always made up of a bunch of compromises.  By playing with other engine parameters (such as port, combustion chamber  or even software design), they can sometimes hit their emissions and economy targets without EGR.

I have worked on Acura Integra engines for example, where the same year engine has EGR on the cars with an automatic transmission, and do not have EGR on the engines with manual transmissions.

I am sure if Chrysler figured out how to hit the emissions and economy objectives without adding EGR, the bean counters would happily tell them not to add it...