Currently experimenting with the EGR disconnected on my 2001 VW Beetle. I have built an EGR emulator to keep the MAF input to the computer within the range it expects when EGR is commanded. I have retained the factory setting of 270 mg/stroke at idle with the EGR duty between 35% and 75%. This is to keep the EGR code from being set and the computer changing the engine fueling to compensate for the lack of EGR.
I have baselined two fuel tanks of pump diesel with EGR functional, and will be entering those on my fuel log. I am now operating without EGR. The warmup time is significantly affected, and to compensate I have partially blocked off the radiator. I had to trim out more cardboard as I was exceeding the thermostat temperature at the end of my morning drive. Once I have a pair of tanks baselined with this configuration, I will re-enable the EGR and compare to a new baseline retaining the grille block (my current baseline was not done with the block). Then I will probably disable the EGR for good, and make my EGR emulator circuit available to purchase on Ebay, hopefully with good data to backup any mileage improvement claims I can make.
Here are pictures of my grille:
Happy dieseling from the Oil Burner Kartel!