EGR deleted should I plug?

[51 Turbo]

My Regal Sport motor is in a 51 Chevy. The EGR is already gone and I'm wondering if I should plug the exhaust gasses from passing into the manifold completely. I can use every bit of "richness" I can get.

 

[earlbrown]

Replacing burnt air with fresh air will actually lean the mixture.

 

[51 Turbo]

Replacing burnt air with fresh air will actually lean the mixture.

wouldn't I be replacing burnt air with the fuel/air mixture?

 

[Paul Lohr]

With the EGR circuit operating normally, in the cylinder let's assume you had 7% fuel, 90% air, and 3% exhaust gas. These numbers are made up just so we can think about the issue.

Now we disable the EGR circuit and the 3% exhaust gas is no longer present. Does the engine have additional breathing capacity to replace the 3% exhaust gas with air? If the 3% is replaced by fresh air, you have the same quantity of fuel and more air. There is a leaner condition. This assumes the ECM has made no adjustment to the fuel quantity.

Of course this is also dependent upon the load on the engine and the RPM. There may be additional breathing capacity at some load/RPM combinations but not at others.

If you have a block-off plate where the EGR valve used to be, I don't think exhaust gas can make it into the intake manifold (except from an un-optimized exhaust system).

 

[jlat]

hello people; Of the main subject but 51. What is a regal sport motor? I'd like to see the install as there has to be a ton of room in there.
thanks
IBBY

 

[51 Turbo]

With the EGR circuit operating normally, in the cylinder let's assume you had 7% fuel, 90% air, and 3% exhaust gas. These numbers are made up just so we can think about the issue.

Now we disable the EGR circuit and the 3% exhaust gas is no longer present. Does the engine have additional breathing capacity to replace the 3% exhaust gas with air? If the 3% is replaced by fresh air, you have the same quantity of fuel and more air. There is a leaner condition. This assumes the ECM has made no adjustment to the fuel quantity.

Of course this is also dependent upon the load on the engine and the RPM. There may be additional breathing capacity at some load/RPM combinations but not at others.

If you have a block-off plate where the EGR valve used to be, I don't think exhaust gas can make it into the intake manifold (except from an un-optimized exhaust system).

The block off plate does let the gasses through and also is essential to the mounting of the turbo/carb assembly. I now have it blocked off and I don't see any difference in performance. My hope is that the intake will be cooler and cleaner. I run so lean at 10Lbs. of boost I don't think this will make a difference. Thanks, Paul

 

[51 Turbo]

hello people; Of the main subject but 51. What is a regal sport motor? I'd like to see the install as there has to be a ton of room in there.
thanks
IBBY

I just had the turbo off for some cleanup and new valve cover gaskets. I'll take a shot this afternoon and post it. It is a sweet install.

 

[dr_frankenstein]

This is carb turbo motor eh? super cool!

 

[51 Turbo]

This is carb turbo motor eh? super cool!

Yeah this is the predecessor to the Grand National. Buick found it was a dog out of the gates so they added fuel injection, and all those sensors and stuff. Still a dog but once it goes into boost it rocks. Chirp the tires into second.

 

[dr_frankenstein]

Hell yea!

join us down in the Before Black Section down in the forum list some.... we can help ya out better.... thats where all us red-headed step children hang out.

 

[dr_frankenstein]

oh yea its debatable by many weather to plug or not on the EGR,

On My carb turbo systems i plug it and remove the assembly.