Not exact A-B-A data but here is some info following recent data-logging:
Same stretch of road, same tires, same speed and it's in a straight line, so the transfer case shouldn't make such a difference.
May 20 test:
Old transfer case
55F outside, light rain, no wind
22.08 milligrams / stroke average injection quantity
4 psi average boost
July 19 test:
New transfer case
64F, cloudy, no wind
20.53 milligrams / stroke average injection quantity
3.26 psi average boost
That shows a 7.27% difference, seems pretty big, I can't wait to get run through a full tank and see actual numbers
Usually the car's trip computer shows between 33.6 and 32.6 MPG (it's optimistic, I've compared it in the past with actual fuel consumption) on national roads. This includes inclines, passing slow cars, speed limits in villages, not exactly good for eco driving.
This time, I reset the trip computer when I left home and at the end of the trip it showed 36.75 MPG, over 231 miles. I've never seen it so low before the transfer case swap, not even on long distances on highways.
Next mod, already ordered: straight through muffler, because it allows me to tuck the exhaust higher for off-road clearance. The stock muffler is baffled and I hope less restriction post-turbo will reduce pumping losses, hopefully some FE gains there too.