Originally Posted by Lawdog's Smokewagon
Starting to gather parts and pieces. I have a couple of questions regarding pipe size. I don't remember seein this in the 1st 4900 posts i have read. Is there a big difference in 3/4" vs 1" pipe nipples and ball valves in regards to temp control and airflow? Also ball valve vs gate valve on intake? Thanks for any light ya'll can shine on this subject.
If you want to look at calculations, check out this post below. It describes different ways to get roughly the same circular area for intake or exhaust.
I think without question, the average and most common configuration is three 3/4 intakes, with 1 and a half of them open to maintain 225. If you use larger holes, you'll have to figure out what works.. certainly it won't be 1 and a half; it would be less.
What I do now with a new drum I made, is eight 1/2 inch holes, and I leave 3 of them open to maintain 225.. at some point I may open a 4th after several hours. This, however, is directly tied to the CONFIGURATION of my exhaust. If I have just one 2 inch hole in the lid, the draft is stronger. If I add a little pipe to that, it becomes significantly stronger. In my new drum I have another eight 1/2 holes in the lid which adds up to the same circular area as the single 2 inch hole. It creates a very mild draft but adequate to keep the fire going. I like this because I think it keeps the food moist and allows for that yummy flavored smoke to really sink in. Best of all, it does not burn as much fuel to do all this.
And oh by the way, you may ask "if you only use 3 or 4 of the holes, why make 8 of them?"
Because sometimes I like to smoke chicken and turkey at much higher temp. It makes the skin nice and crispy and doesn't take as long. To do that, I would leave all 8 holes open and that lets me sit between 350 and 400.