Originally Posted by dozerrn
any ideas how it will run without an EGR and a proper tune? simple answer is all I'm looking for.... better? worse? sluggish? more or less efficient?
Generally speaking, running with EGR means your engine is more spark tolerant (recirculated exhaust gases cools down the combustion chamber), i.e. you can bump up the spark advance schedule which results in better fuel economy. This also means if you use the same engine computer and not install the EGR, you may experience spark knock and your knock sensor system will try to reduce spark advance which will result in worse FE (plus your check engine light will turn on).
If the engine is properly calibrated, there should be no perceived difference on how the engine runs, it will just affect your FE.