Cummins X15, what's the word?

[Running rough]

having one on the farm x15 that is with my demandate, demandated with 565 1850 its pretty peppy on the preformance aspect on trains, i try and use safe timing so engine life is not reduced, it defintley has the torque down low but i dont run it there for very long, i try and keep rpms 1500 and up when pullin hard, our cm2250s have also been flawless with @m*m^2 demandate, but i made sure fuel pumps were updated, going back to x15 performance tuning, first timing on demandate was slightly to delayed or retarded, this is where you notice performance and fuel economy is not quite where it should be, with some playing you try and find the bleeding edge of fuel economy and engine longevity, leaning towards lovgevity