Okay, first time posting and looking for some help I am trying to get a friends vertical offset to maintain a good cooking temp but i cannot. It just does not seem to draw well enough. I cannot get it to hold much above 200 with charcoal only. The tank is 64 in tall with a 24 in diameter. The opening between the firebox and the tank is a 6 in circle. The firebox has expanded metal with 3 in of clearance off the bottom for air. The vent is a wheel type with two triangular slits that are 3 in at the widest point. I thought the 4 in hole in the bottom for the supplemental gas burner was letting in cold air so i added the pictured pipe on the bottom. I cut off the hole completely and that was not the problem. My hunch now is the stack may be too small. It is a 3 in pipe having a 2.5 in ID. Does anyone have a formula used to figure stack size? My simple way of thinking tells me the vertical configuration is ideal for drafting, much like a chimney in your house. I would appreciate any and all help on this. It is a very versatile unit and i would love to get it working at its maximum efficiency. Thanks
