I have done a lot of reading about blocking of the egr valve. Can someone explain what that does and what effect it will have? I know it has something to do with emissions. Is there any other emissions stuff that can be taken off if you block the egr with a plate? Just trying to figure all this out so any help would be great.

 

EGR helps reduce NOx (oxides of nitrogen). That's one of the three things they typically check with a dyno emissions test (CO, HC and NOx). Removing the EGR does not do anything for power.... it isn't even used at WOT or high RPM. The EGR flow reduces the combustion chamber temps, when the PCM sees operating conditions that can cause excessive temperatures. Its the high temperatures that cause NOx to form. The exhaust gas displaces some of the A/F mixture, so there is less heat from combustion. A side benefit is a reduction in the tendancy to detonate, when lugging the engine at low RPM in the wrong gear.

The usual reasons for deleting EGR are "cleans up the engine comparment" (but most of it is hidden behing the intake and under the cowl), and "eliminates the heat that (may) cause the infamous LT1 intake oil leak".

 

People have also removed the AIR and EVAP systems. Frankly, if you have emissions to satisfy, I wouldn't be tampering with any of these systems too much. As Injuneer noted, the EGR is not even noticable and one of the big reasons that people remove it is to clean up the engine bay. The AIR system seems to stand out more then anything, but once again, if you have emissions regulations to meet, I wouldn't mess with these.

 

I don't have emissions to meet here in MO. anything 95 and older but I believe it is all working fine so i don't plan on messing with it now. just curious what the total function of it was. Thanks for the answers.