So all this time I have been burning it according to what sbi suggest in the owners manual. Fill firebox with desired load of wood and let it go thru its whole cycle. Once you burn that down and you notice its cooling off reload again. Repeat and repeat. A few days ago I loaded when I woke up filled firebox. about 45 mins later (peak burn) came back down before heading to work and figured heck I can squeeze a couple more pieces now that everything has settled down in firebox. So I put a couple pieces on top and closed door. I never opened damper. My secondary burn almost doubled. Increased my stack temp about 15*- 20*. I have tried this now for the past few days with the same results. I know the tundra likes to run in secondary mode which it was designed for. I figure if I can get more heat out of it this way why not. Wondering if anyone else has tried running it this way with this same results? I know adding the fresh wood while in peak burn (almost melts my hands trying to load at this point ) causes more smoke for the secondaries to burn off. Anyone else been burning it this way?