My 2009 Caterpillar engine had over 968,000 miles and was recently rebuilt when I started using Enerburn. I started out with a clean DPF and a new ARD head. The first thing I noticed was a smoother, quieter engine and better engine performance, then the MPG started to increase from 6.3 to 7.6 by the end of the first two months of using Enerburn. I am now seeing 8.0 mpg for the first time ever on this truck and have had to do only 2 manual regens in the last 29,000 miles since using Enerburn. My fuel savings is 4X the cost of Enerburn over this same period.