Benefits of an EGR Delete?

[stephenssei]

Hey guys, I'm sure this question has been answered already but I searched and couldn't find what i was looking for. I've been having the issue with the EGR Valve sticking open and it's currently getting fixed again after having a new fuel pump and float being put in and my mechanic mentioned that he had another Bonneville in the shop a while back with an EGR Delete and it made me somewhat curious.

As I understand it, the EGR is really only there to help with emissions but I don't really understand fully, and because of that I wasn't;t really sure what an EGR delete would even benefit. If there is a thread where this is already answered and someone could give a link to me it would really be appreciated since I couldn't find one when i searched the forum.

Also BTW, having that new fuel pump really did feel a good bit better, the mechanic said that he was surprised that the car was even getting fuel it was so full of carbon. But 20+ years with the stock pump isn't bad.
Thanks guys!

[RJolly87]

It's all emissions, with maybe a slight bit of engine longevity as well.

Early L27 (91-92) that had an aluminum UIM didn't even have an EGR system.

The technicals:
https://en.wikipedia.org/wiki/Exhaust_gas_recirculation

In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline and diesel engines. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. This dilutes the O2 in the incoming air stream and provides gases inert to combustion to act as absorbents of combustion heat to reduce peak in-cylinder temperatures. NOx is produced in a narrow band of high cylinder temperatures and pressures.
In a gasoline engine, this inert exhaust displaces the amount of combustible matter in the cylinder. In a diesel engine, the exhaust gas replaces some of the excess oxygen in the pre-combustion mixture.[1] Because NOx forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature, the lower combustion chamber temperatures caused by EGR reduces the amount of NOx the combustion generates (though at some loss of engine efficiency).[2] Gasses re-introduced from EGR systems will also contain near equilibrium concentrations of NOx and CO; the small fraction initially within the combustion chamber inhibits the total net production of these and other pollutants when sampled on a time average. Most modern engines now require exhaust gas recirculation to meet emissions standards.

[stephenssei]

So basically, it's "de-tuning" your engine to be a little more compliant with emissions, and instead of just outputting the exhaust gas, the gas is just recirculated into the engine? (If I'm interpreting this correctly)

[RJolly87]

Essentially, it's to dial the combustion temps down a bit, hopefully out of the range that causes NOX emissions.

With no EGR, the early L27's were slightly more susceptible to burning valves.

[maxi426]

Typically, engines with EGR are programmed with more ignition timing, especially at light throttle cruise conditions. With the EGR deleted, spark knock is a possibility. I wouldn't do this unless you were able to monitor knock retard at part throttle with a scan tool for a while. Sometimes going up in octane is necessary.

[00Beast]

There aren't any on a stock 3800, only disadvantages.

[Jrs3800]

Essentially, it's to dial the combustion temps down a bit, hopefully out of the range that causes NOX emissions.

With no EGR, the early L27's were slightly more susceptible to burning valves.

This 100%... The 1991-1992 did not need an EGR valve to pass emissions, yes they were that clean even back then.. But GM found that the EGR'less 3300 and 3800's were burning valves.. In 1993 GM started using the EGR once again and continued till the end of production.

[Wes]

I was told by a tuner that the EGR closes at WOT anyway. So performance wise under full load, there is no difference if he is correct.

Something I would consider a benefit is that the intake side of things will have less soot if the EGR is bypassed, but that's about it. People make a bigger deal about the EGR systems than it deserves, imo.